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MCQs for Oral Microbiology

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MCQs for Oral MicrobiologyElsevier Ltd.

Revised and Updated Edition

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v

Preface vii

Acknowledgments viii

1 Introduction 1

2 The Mouth as a Microbial Habitat 5

3 The Resident Oral Microflora 20

4 Acquisition, Adherence, Distribution and Metabolism of the Oral Microflora 37

5 Dental Plaque 59

6 Plaque-Mediated Diseases—Dental Caries and Periodontal Diseases 75

7 Orofacial Bacterial Infections 101

8 Antimicrobial Prophylaxis 118

9 Oral Fungal Infections 130

10 Orofacial Viral Infections 143

11 Oral Implications of Infection in Compromised Patients 155

12 Infection Control 173

Index 187

C O N T E N T S

vii

P R E F A C E

For students, a good way to test their understanding and knowledge about a particular subject and to prepare for exams is to practice using Multiple Choice Questions (MCQs). This book on MCQs for Oral Microbiology has been written keeping in mind the above purpose.

In this book Elsevier has worked with professional question writers to prepare a collection of 500 MCQs to accompany the subject matter covered in each chapter of the textbook, Oral Microbiology, 5th edition by Philip D. Marsh and Michael V. Martin (ISBN: 978-0-443-10144-1). The style of MCQs is three distractors and one correct answer so the student will need to mark the correct option accordingly. Each chapter is followed by a feedback section showing the correct answers and a very quick rationale why each answer is correct or incorrect thus elevating student’s confidence to answer many more MCQs on the subject. Below each rationale, reference to the page number of the main textbook, Oral Microbiology, is given for the students who want to revise or study the particular topic again.

The aim for the student is to get as many correct as possible, and to revise any subject area where the number of correct marks is low. We sincerely hope that students will find the book extremely useful. We welcome comments and suggestions from students and teachers, which will help in improving this book further.

Elsevier Ltd.

viii

A C K N O W L E D G M E N T S

The publisher would like to thank Professor P. D. Marsh and Professor D. W. Williams for their insightful feedback in reviewing this book. The publisher would also like to thank Sherry Castle Boyer and her team for their efforts in preparing the multiple choice questions.

1

C H A P T E R 1

Introduction

Multiple Choice1. Inmicrobialecology,whichofthefollowingtermsdescribesthesitewheremicroorganisms

grow?a. Niche.b. Habitat.c. Ecosystem.d. Community.

2. Whichofthefollowingistrueaboutresidentmicrofloraofahost?a. Themicroflorahasapassiverelationshipwithitshost.b. Resident microflora contributes directly to the normal development of the defence

systemsofthehost.c. Residentmicrofloraisthesameforeachindividual.d. Residentmicrofloramakeuparound10%ofcellsofthehumanbody.

3. Anexampleofanendogenoussourcethatcancreateachangeinthebiologyofthemouthwouldbewhichofthefollowing?a. Changeintheintegrityofthehostdefences.b. Useofanantimicrobialoralrinse.c. Antibiotictreatment.d. Increaseintheintakeoffermentablecarbohydrates.

4. Themouthcanactasareservoirforwhichofthefollowingpathogens?a. Helicobacter pylori.b. Pseudomonas aeruginosa.c. Respiratorypathogens.d. Alloftheabove.

5. Themicrobialcolonisationofallenvironmentallyaccessiblesurfacesofthebodybeginsatwhichofthefollowing?a. Birth.b. Breast-feeding.c. Onemonthpost-breastfeeding.d. Eatingsolidfoods.

6. Streptococciarenotaresidenthumanmicrofloraofwhichofthefollowingsites?a. Nasopharynx.b. Mouth.c. Uro-genitaltract.d. Gut.

2 1—IntroductIon

7. The human body is estimated to be made up of 1014 cells; what proportion aremicroorganisms?a. <0.01%.b. 1%.c. 20%.d. 90%.

8. Of the following, which is not a reason for disparities in oral healthcare within apopulation?a. Socio-economicstatus.b. Race.c. Lackofdentaleducation.d. Ethnicity.

9. Whatisthetermusedtodescribethegrowthofmicroorganismsonasurface?a. Microbialcommunity.b. Biofilm.c. Niche.d. Ecosystem.

10. Evidencesuggeststhatoraldiseasecanaffectthegeneralhealthofanindividualbywhichofthefollowingmeans?a. Factors affecting general health can enter the bloodstream via the highly vascularised

periodontium.b. Ageneticpredispositiontoasystemicdisease.c. Thepresenceofnon-opportunisticpathogensinthemouth.d. Inadequatenutrition.

Feedback1. ANS:b

a. The‘niche’isthe‘function’or‘role’ofamicroorganisminahabitat.b. Correct.Thehabitatisdefinedasthesitewheremicroorganismsgrow.c. Ecosystem is a combination of the microorganisms and the habitat together with the

bioticandabioticsurroundings.d. The mixture of microorganisms growing in a particular habitat is a microbial

community.

REF:Microbialecology,pp.4–5

2. ANS:ba. Themicroflorahasacontributoryrelationshipwithitshost.b. Correct. Resident microflora contributes directly to the normal development of the

defencesystemsoftheorganism.c. Residentmicrofloraisdistinctforeachindividual.d. Residentmicrofloramakeupsignificantlymorethan10%ofcellsofthehumanbody.

REF:Thehumanmicroflora,pp.1–2

1—IntroductIon 3

3. ANS:aa. Correct.Endogenouschangessuchasalterations in the integrityof thehostdefences

duetodrugtherapyperturbthenaturalstabilityofthemicroflora.b. Majorchanges to thebiologyof themouthfromexogenoussources includeantibiotic

treatment,useofantimicrobialoralrinses,orthefrequentintakeoffermentablecarbo-hydratesinthediet.

c. Majorchanges to thebiologyof themouthfromexogenoussources includeantibiotictreatment,useofantimicrobialoralrinses,orthefrequentintakeoffermentablecarbo-hydratesinthediet.

d. Majorchanges to thebiologyof themouthfromexogenoussources includeantibiotictreatment,useofantimicrobialoralrinses,orthefrequentintakeoffermentablecarbo-hydratesinthediet.

REF:Theoralmicroflorainhealthanddisease,pp.2–3

4. ANS:da. Helicobacter pyloricanbedetectedindentalplaqueonoccasions.b. Pseudomonas aeruginosacancolonisethemouthofpatientswithcysticfibrosis.c. Respiratorypathogenscanbedetectedindentalplaqueinpatientsinintensivecare.d. Correct.Allofthesepotentialpathogenscanbedetectedinthemouthonoccasions.

REF:Theoralmicrofloraingeneralhealth,pp.5–6

5. ANS:aa. Correct.Themicrobialcolonisationofallenvironmentallyaccessiblesurfacesofthebody

(bothexternalandinternal)beginsatbirth.Suchsurfacesareexposedtoawiderangeofmicroorganismsderivedfromtheenvironmentandfromotherpersons.

b. Themicrobialcolonisationofallenvironmentallyaccessiblesurfacesofthebody(bothexternalandinternal)beginsatbirth.

c. Themicrobialcolonisationofallenvironmentallyaccessiblesurfacesofthebody(bothexternalandinternal)beginsatbirth.

d. Themicrobialcolonisationofallenvironmentallyaccessiblesurfacesofthebody(bothexternalandinternal)beginsatbirth.

REF:Thehumanmicroflora,p.2

6. ANS:da. Streptococcusisaresidenthumanmicrofloraofthemouth,nasopharynx,anduro-genital

tract.Itisnotamajorresidentofthegut.b. Streptococcusisaresidenthumanmicrofloraofthemouth,nasopharynx,anduro-genital

tract.Itisnotamajorresidentofthegut.c. Streptococcusisaresidenthumanmicrofloraofthemouth,nasopharynx,anduro-genital

tract.Itisnotamajorresidentofthegut.d. Correct.Streptococcusisaresidenthumanmicrofloraofthemouth,nasopharynx,and

uro-genitaltract,butnotofthegut.

REF:Thehumanmicroflora,Figure1.1,p.2

4 1—IntroductIon

7. ANS:da. Thehumanmicrobiomeisestimatedtomakeup90%ofthecellsofthehumanbody.b. Thehumanmicrobiomeisestimatedtomakeup90%ofthecellsofthehumanbody.c. Thehumanmicrobiomeisestimatedtomakeup90%ofthecellsofthehumanbody.d. Correct.Thehumanmicrobiomeisestimatedtomakeup90%ofthecellsofthehuman

body.

REF:Thehumanmicroflora,Figure1.1,pp.1–2

8. ANS:ca. Profounddisparitiesinoralhealthexistwithinapopulationduetodifferencesinsocio-

economicstatus(SES)andraceorethnicity.b. Profounddisparitiesinoralhealthexistwithinapopulationduetodifferencesinsocio-

economicstatus(SES)andraceorethnicity.c. Correct.Lackofdentaleducationisnotareasonprofounddisparitiesinoralhealthexist

withinapopulation.d. Profounddisparitiesinoralhealthexistwithinapopulationduetodifferencesinsocio-

economicstatus(SES)andraceorethnicity.

REF:Thescaleoforaldisease,p.3

9. ANS:ba. Amicrobialcommunityisamixtureofinteractingmicroorganisms,butthesedonothave

tobeonasurface,althoughthisiswheretheyarenormallyfound.b. Correct.Abiofilmisthetermusedtodescribemicroorganismsgrowingonasurface.c. The niche describes the ‘function’ or ‘role’ of a microorganism within a microbial

community.d. Theecosystemisacombinationofthemicroorganismsandthehabitattogetherwiththe

bioticandabioticsurroundings.

REF:Microbialecology,pp.4–5

10. ANS:aa. Correct.Factorsofinfectionenteringthebloodstreamviathehighlyvascularisedperi-

odontiumarenowbelievedtoaffectdistantsitesinthebody.b. Ageneticpredispositiontoasystemicdiseasedoesnotnecessarilyinfluencetherelation-

shipbetweenoralandsystemicdisease.c. Thepresenceofnon-opportunisticpathogensinthemouthdoesnotaffectgeneralhealth.d. Inadequatenutritionisacontributingfactortooraldiseasebutnotthelinkbetweenoral

andsystemichealth.

REF:Oralmicrofloraandgeneralhealth,p.5

5

C H A P T E R 2

The Mouth as a Microbial Habitat

Multiple Choice1. Thelargemassesofmicroorganismsthataccumulateonthehard,non-sheddingsurfaceof

theoralcavityaredescribedbywhichofthefollowingterms?a. Flocs.b. Aggregates.c. Biofilms.d. Microcosm.

2. TheshiftinoralmicrofloracompositionthatfostersovergrowthbyGramnegativespeciesduetoablockinsalivaryflowinsedatedpatientsinintensivecarecanleadtowhichofthefollowing?a. Desquamation.b. Increaseingingivalcrevicularfluid(GCF)flow.c. Pulmonarycomplications.d. Increaseindefensins.

3. Whichofthefollowingdoesnotfacilitateachangeintheecologyoftheoralcavity?a. Reductioninsalivaryflow.b. Typeoffoodingested.c. Pyrexia.d. Dentaltreatment.

4. Whichofthefollowingsurfacesactsasahabitatforthelargestnumberofmicroorganismsthatotherwisemightberemovedbytheflowofsalivaormasticatoryforces?a. Lips.b. Cheeks.c. Tongue.d. Palate.

5. Whichofthefollowingoralsurfacesisnon-sheddingandfacilitatesmicrobialcolonisation?a. Oralmucosa.b. Vestibularsurface.c. Enamelsurface.d. Palate.

6. Whichofthefollowingarenotinnatehostdefencepeptides?a. sIgA.b. Cystatins.c. Secretoryleucocyteproteinaseinhibitor(SLPI).d. Tissueinhibitorsofmetalloproteinases(TIMP).

6 2—THe MouTH as a Microbial HabiTaT

7. Whichofthefollowingsalivarycomponentsdonotplayakeyroleincontrollingbacterialandfungalcolonisationofthemouth?a. Minerals.b. Salivarymucins.c. Salivarylactoperoxidase.d. Cathelicidin.

8. Whichofthefollowingisnotpartoftheadaptivehostresponseinthemouth?a. IgG.b. IgM.c. IgA.d. Lysozyme.

9. Mucinsplayaroleinwhichofthefollowing?a. Providingsupporttocellwalls.b. Inhibitingglycolysis.c. Blockingofinflammatorymediators.d. Beingasourceofnutrientsfororalbacteria.

10. Whichofthefollowingisnotatissuethatispartofthetoothstructure?a. Cementum.b. Gingiva.c. Dentin.d. Enamel.

11. Which of the following affords colonising microorganisms the most protection from theadverseconditionsinthemouth?a. Dorsumofthetongue.b. Unattachedgingiva.c. Occlusalsurfaceoftooth.d. Gingivalcrevice.

12. Whichofthefollowingisanarea/surfaceintheoralcavityusedforacquiringsubgingivalplaquesamples?a. Occlusalaspect.b. Mucosalsurfaces.c. Dorsumoftongue.d. Gingivalcrevice.

13. Whichofthefollowingisnotafactorbywhichsalivainfluencesthemicrofloraofthemouth?a. Formationofaconditioningfilm.b. Providingproteinsandglycoproteinsforbacterialgrowth.c. ProvidinganeutralpHandactingasabufferformicrobialgrowth.d. Deliveringneutrophilsandcomplementtokillmicroorganisms.

14. Whichof the following tooth surfacesprovide themostprotection tomicroorganisms intheoralcavity?a. Lingualsurfaces.b. Approximalareas.c. Buccalsurfaces.d. Pitsandfissures.

2—THe MouTH as a Microbial HabiTaT 7

15. Whichofthefollowingtoothsurfacesareassociatedwiththelowestmicrobialcommunitiesanddisease?a. Smoothsurfaces.b. Approximalsurfaces.c. Rootsurfaces.d. Pitsandfissures.

16. Which of the following is found in the highest concentration in saliva comparedwithGCF?a. IgG.b. Amylase.c. Calcium.d. Protein.

17. Salivaentersthemouththroughmajorsalivaryductsincludingwhichofthefollowing?a. Submandibularandbuccalglands.b. Parotid,submandibularandsublingualglands.c. Labialandlingualglands.d. Buccalandpalatalglands.

18. WhichofthefollowingisfoundinthehighestconcentrationinGCFcomparedwithsaliva?a. IgM.b. Lysozyme.c. Phosphate.d. Potassium.

19. Themajorbufferingsysteminsalivaismadeofwhichofthefollowing?a. Bicarbonate.b. Phosphates.c. Peptides.d. Proteins.

20. Whyisitimportanttolimittheconsumptionofsugarydrinksorfoodpriortosleeping?a. Causeshalitosis.b. Increasestheriskofbecomingdiabetic.c. Fracturesrestorations.d. Encouragesdentalcaries.

21. The major organic components of saliva (proteins and glycoproteins) influence the oralmicroflorainwhichofthefollowingways?a. Limitingtheabilityofallmicroorganismstoattachtothetoothsurface.b. Actingasaprimarysourceofnutrients.c. Preventingcolonisation.d. IncreasingcolonisationofGramnegativeorganismsonly.

22. Followingthedietaryintakeoffermentablecarbohydrates,themetabolismofwhichofthefollowingcontributestotheriseinpH?a. Sodium.b. Calcium.c. Aminoacids.d. Albumin.


23. Whichistheclassofenzymeresponsibleforremovingcarbohydratesfromthesidechainsofsalivarymucins?a. Glucosyltransferase.b. Glycosidase.c. Fructosyltransferase.d. Amylase.

24. Ninety-fivepercentoftheleukocytesinGCFarewhichofthefollowingtypes?a. Neutrophils.b. Lymphocytes.c. Monocytes.d. Macrophages.

25. Whichaspectoftheoralcavityprovidesstableconditionssuitableforthegrowthofawiderangeofmicroorganisms?a. AhighpH.b. Gingivalcrevicularfluidsecretion.c. Antibodyproduction.d. Relativelyconstanttemperature.

26. Ariseinthetemperatureinaperiodontalpocketcansignalwhichofthefollowingevents?a. Rootcaries.b. AdiminishedflowofGCF.c. Inflammation.d. Halitosis.

27. Ofthefollowing,whichenvironmentalfactormostgovernsthesurvivalandrelativegrowthofobligatelyanaerobicorganisms?a. HighpH.b. LowpH.c. Increasedoxygenlevels.d. Lowoxidation-reductionpotential.

28. Oxidation-reductionlevelatasiteisusuallyexpressedaswhichofthefollowing?a. Eh.b. Percentageoxygenlevel.c. pH.d. Oxygenconsumptionratio.

29. Oralmicroorganismsareseparatedintoaerobesandanaerobesbasedonwhichofthefol-lowingcharacteristics?a. Growsinplaquebiofilm.b. Growsintheabsenceorpresenceofoxygen.c. Growsintheabsenceorpresenceofhydrogen.d. Growsinthepresenceorabsenceofcarbondioxide.


30. Lactobacillusspeciesprefertogrowatwhichofthefollowingconditions?a. NeutralpH.b. AcidicpH.c. AlkalinepH.d. Alloftheabove.

31. Thepersistenceanddiversityoftheresidentoralmicrofloraonmucosalsurfacesisprimarilyduetothemetabolismofwhichofthefollowing?a. GCF.b. Dietaryfactors.c. Endogenousnutrientsprovidedbythehost.d. Exopolymers.

32. Despitethecomplexityofingestedfood,themetabolismofwhichclassofcompoundsig-nificantlyinfluencestheecologyofthemouth?a. Nitrateingreenvegetables.b. Dairyproducts.c. Fermentablecarbohydrates.d. Xylitol.

33. Analternativeterminologyfornon-specificandspecifichostdefencefactorsiswhichofthefollowing?a. Hydrophilicandbacterialaggregatingfactors.b. Innateimmunityandadaptiveimmunityfactors.c. Antigenactivityandbroadspectrumfactors.d. Physiochemicalandimmunologicalbarriers.

34. Microorganisms areunable tomaintain themselves in salivaby cell division alonedue towhichofthefollowingfactors?a. Chewing.b. GCFflow.c. Swallowing.d. Reducedsalivaflow.

35. Defensinsareafamilyofpeptidesthathavewhichofthefollowingproperties?a. Specificantifungalactivity.b. Neutralisingpotentiallyinflammatoryprocesses.c. Inhibitionofglycolysisbyplaquebacteria.d. Broadspectrumantimicrobialactivity(antibacterial,antifungalandantiviralactivity).

36. Porphyromonas gingivalisisanobligateanaerobewhichpreferstogrowata. NeutralpH.b. AcidicpH.c. AlkalinepH.d. Alloftheabove.


37. Whichisthepredominantimmunoglobulininsaliva?a. SecretoryIgA.b. IgG.c. IgM.d. IgA.

38. An analysis of the microflora of twin children living together revealed which of thefollowing?a. Microfloraofidenticaltwinswaslesssimilarthanthatoffraternaltwins.b. Therewasnodifferencebetweenthemicrofloraofidenticaltwinsfromthatoffraternaltwins.c. Microfloraofidenticaltwinswasmoresimilarthanthatoffraternaltwins.d. There is no relationship of microflora to any aspect of the relationship of children to

eachother.

39. Currently,themostpotentantimicrobialagent(s)availableinamouthrinseiswhichofthefollowing?a. Sodiumlaurylsulphate.b. Plantextracts.c. Chlorhexidine.d. Fluoride.

40. Takinghighdosesofpenicillinorerythromycincan result inwhichof the followingoralsequela?a. Reductioninsalivaryflow.b. Overgrowthbyyeastsortheemergenceofantibiotic-resistantbacteria.c. Developmentofacid-toleratingorganisms.d. Anincreasedpresenceofhistatins.

Feedback1. ANS:c

a. Flocsareaggregatesofmicroorganisms,butthetermisnotusedtodescribebacteriaonteeth.

b. Aggregatesareclumpsofmicroorganisms,butthetermisnotusedtodescribebacteriaonteeth.

c. Correct.Biofilmisamassofmicroorganismsthataccumulatesonoralsurfaces.d. A microcosm is a laboratory simulation of a microbial ecosystem, but is not used to

describethebacteriaonatoothsurface.

REF:Themouthasamicrobialhabitat,p.8

2. ANS:ca. Desquamationisthenaturalsheddingofepithelialcellsandisnottheresultofablockage

tosalivaryflow.b. AnincreaseinGCFisnottheresultofablockagetosalivaryflow.c. Correct.Whensalivaflowisblocked(forexample,insedatedpatientsinintensivecare)

a shift in the compositionof theoralmicroflora canoccur resulting inovergrowthbyGramnegativespecies,andthiscanleadtopulmonarycomplications.

d. Anincreaseindefensinsisnottheresultofablockagetosalivaryflow.

REF:Innateimmunity,p.18


3. ANS:ca. Areductioninsalivaryflowcanchangetheecologyoftheoralcavity.b. The types of food ingested, such as carbohydrates, can alter the pH balance and the

ecologyoftheoralcavity.c. Correct.Anincreaseordecreaseinbodytemperaturedoesnotfacilitateachangeinthe

ecologyoftheoralcavity.d. Dentaltreatments,suchasscaling,placementofrestorationsorinsertionoforthodontic

bands,cancausetransientfluctuationsinthestabilityoftheoralecosystem.


4. ANS:ca. Lipsdonotproviderefugeformanymicroorganismswhichwouldotherwiseberemoved

bymasticationandtheflowofsaliva.b. Cheeks do not provide refuge for many microorganisms which would otherwise be

removedbymasticationandtheflowofsaliva.c. Correct.Thepapillarystructureofthedorsumofthetongueprovidesrefugeformany

microorganismswhichwouldotherwiseberemovedbymasticationandtheflowofsaliva.d. Thepalatedoesnotproviderefugeformanymicroorganismswhichwouldotherwisebe

removedbymasticationandtheflowofsaliva.


5. ANS:ca. Oralmucosaisnotanon-sheddingsurface.b. Vestibularsurfaceisnotanon-sheddingsurface.c. Correct.Enamelprovideshardnon-sheddingsurfacesformicrobialcolonisation.d. Palateisnotanon-sheddingsurface.

REF:Teeth,p.9

6. ANS:aa. Correct.sIgAisanimmunoglobulinandformspartoftheadaptiveimmuneresponse.b. Cystatinsareantimicrobialpeptidesandformpartoftheinnatehostdefences.c. SLPIispartoftheinnatehostdefences.d. TIMParepartoftheinnatehostdefences.

REF:Innateimmunity,p.20

7. ANS:aa. Correct.Whilepresentinsaliva,mineralsdonotplayaroleincontrollingbacterialand

fungalcolonisationofthemouth.b. Salivary mucins play a key role in controlling bacterial and fungal colonisation of the

mouth.c. Salivarylactoperoxidaseisanantimicrobialfactorthatplaysaroleincontrollingbacterial

andfungalcolonisationofthemouth.d. Cathelicidin is an antimicrobial peptide that plays a role in controlling bacterial and

fungalcolonisationofthemouth.

REF:Saliva,p.12


8. ANS:da. IgGisanimmunoglobulinandformspartoftheadaptivehostresponse.b. IgMisanimmunoglobulinandformspartoftheadaptivehostresponse.c. IgAisanimmunoglobulinandformspartoftheadaptivehostresponse.d. Correct.Lysozymeispartoftheinnatehostresponse.

REF:Innateimmunity,pp.18–20

9. ANS:da. Mucinsmayinteractwithsalivarycomponentstoenhancetheirantimicrobialactivities,

butdonotprovidesupporttocellwalls.b. Mucinsmayinteractwithsalivarycomponentstoenhancetheirantimicrobialactivities,

butdonotinhibitglycolysis.c. Mucinsmayinteractwithsalivarycomponentstoenhancetheirantimicrobialactivities,

butdonotplayaroleintheblockingofinflammatorymediators.d. Correct.Mucinsactasprimarysourcesofnutrientsfortheoralmicroflora.

REF:Saliva,p.11

10. ANS:ba. Cementumisatissuethatispartofthetoothstructure.b. Correct.Thegingivaisnotatissuethatispartofthetoothstructure;rather,itisasup-

portivetissue.c. Dentineisatissuethatispartofthetoothstructure.d. Enamelisatissuethatispartofthetoothstructure.

REF:Teeth,p.9

11. ANS:da. Thegingivalcrevice,notthedorsumofthetongue,providesthemostprotectiontocolo-

nisingmicroorganismsfromtheadverseconditionsinthemouth.b. The architecture of unattached gingiva does not provide protection to colonising

microorganisms.c. The occlusal tooth surface is actively involved in the chewing process and does not

provideprotectiontocolonisingmicroorganisms.d. Correct.Duetotheuniquearchitecture,thegingivalcreviceaffordsthemostprotection

tocolonisingmicroorganismsfromtheadverseconditionsinthemouth.

REF:Teeth,p.10

12. ANS:da. Thepitsandfissuresof theocclusal surfacedocollectplaque;however, theyarenota

subgingivalsurface.b. Plaquedoesnotadheretomucosalsurfaces.c. Gingival crevicular fluid does not provide the surface structure necessary for plaque

accumulation.d. Correct. The gingival crevice is the location from which subgingival plaque can be

sampled.

REF:Teeth,p.10


13. ANS:da. Saliva is adsorbed onto teeth to form the acquired pellicle, which promotes bacterial

attachment.b. Saliva contains molecules that can be used as primary nutrients for bacterial

growth.c. MostoralbacteriapreferaneutralpHforgrowth.d. Correct.NeutrophilsandcomplementaredeliveredtothegingivalcreviceviaGCF.

REF:GCF,pp.12–14,Figure2.6,p.11

14. ANS:ba. Thesmoothlingualsurfaceofthetoothwithitsapproximationtothetongueisnotthe

mostconducivelocationtosupportmicrobialcolonisation.b. Correct.Thestagnantapproximalareasbetweenadjacentteethaffordprotectiontocolo-

nisingmicroorganisms.c. Thesmoothbuccalsurfaceofthetoothwithitsproximitytothecheckisnotthemost

conducivelocationtosupportmicrobialcolonisation.d. Pitsandfissuresoftheocclusalsurfacedoharbourmicroorganism;however,theydonot

offerthemostprotectiontotheorganisms.

REF:Teeth,p.10

15. ANS:aa. Correct.The smooth surface of the tooth is the least conducive location to support

microbialcolonisation.b. The stagnant approximal areas between adjacent teeth afford protection to colonising

microorganisms.c. Therootsurfaceisaconducivelocationtosupportmicrobialcolonisation.d. Pits and fissures of the occlusal surface offer the protection required to support

colonisation.

REF:Teeth,p.10

16. ANS:ba. IgGispresentatlowlevelsinsaliva.b. Correct.AmylaseisfoundinhigherconcentrationsinsalivacomparedwithGCF.c. CalciumispresentatalowerconcentrationinsalivathanGCF.d. ProteinispresentatahighconcentrationinGCF.

REF:Saliva,Table2.2,p.11

17. ANS:ba. Thesubmandibularsalivaryglandisconsideredoneofthemajorglands,whilethebuccal

glandsareconsideredminorglands.b. Correct. Salvia enters the oral cavity via salivary ducts from the major parotid, sub-

mandibularandsublingualglands.c. Labialandlingualglandsareconsideredminorsalivaryglands.d. Buccalandpalatalglandsareconsideredminorsalivaryglands.

REF:Saliva,p.11


18. ANS:aa. Correct.IgMispresentathigherconcentrationsinGCF.b. Lysozymeisfoundmainlyinsaliva.c. Phosphateisfoundinbothfluids;itishigherinsaliva.d. Potassiumisfoundinbothfluidsatasimilarconcentration.

REF:Saliva,Table2.2,p.11

19. ANS:aa. Correct.BicarbonateisthemajorbufferingsysteminsalivaaffectingthepHofsaliva

withameanrangeof6.75and7.25.b. Phosphatesalsoplayaroleinthebufferingsystembutarenotthemajorcomponent.c. Peptidesalsoplayaroleinthebufferingsystembutarenotthemajorcomponent.d. Proteinsalsoplayaroleinthebufferingsystembutarenotthemajorcomponent.

REF:Saliva,p.11

20. ANS:da. Halitosisiscausedprimarilybybacteriathatcolonisethetongue,notespeciallyrelated

tosleeptimesnortheconsumptionofsugarydrinksandfood.b. Whilean increase in sugarconsumptionmay increaseone’s riskofbecomingdiabetic,

whenitisconsumeditisnotaconfoundingfactor.c. Dentalrestorationsarenotfracturedbytheconsumptionofcarbohydratesatsleeptime.d. Correct.Sugarcanbemetabolisedtoacidsbydentalplaque,whichcancausedeminer-

alisation.Theconcentrationofselectedcomponentsandflowrateofsalivahaveacirca-dianrhythmwiththeslowestflowofsalivabeingduringsleep,whichlimitstheprotectivefunctionofsaliva.

REF:Saliva,p.11

21. ANS:ba. Themajororganiccomponentsofsaliva(proteinsandglycoproteins)adsorbtothetooth

surface to formafilm(theacquiredpellicle)whichpromotes theattachmentofmanymicroorganisms.

b. Correct.Themajororganiccomponentsofsaliva(proteinsandglycoproteins)influencetheoralmicroflorabyactingastheprimarysourceofnutrients(carbohydratesandpro-teins)fortheresidentmicroflora.

c. Themajororganiccomponentsofsaliva(proteinsandglycoproteins)promotemicrobialcolonisationbyformingtheacquiredpellicle.

d. Themajororganiccomponentsofsaliva(proteinsandglycoproteins)providethenutri-entsforthegrowthandtheacquiredpellicleforcolonisationofbothGrampositiveandGramnegativeorganisms.

REF:Saliva,p.11


22. ANS:ca. SodiumisacomponentofwholesalivaandGCF.b. CalciumisacomponentofwholesalivaandGCF.c. Correct.Themetabolismofaminoacids,peptides,proteinsandureacanleadtoarise

inpHafterthedietaryintakeoffermentablecarbohydrates.d. AlbuminisacomponentofwholesalivaandGCF.

REF:Saliva,p.12

23. ANS:ba. Glycosyltransferasesremoveglucosefromsucrosetoformglucans.b. Correct. Various glycosidases remove different carbohydrates from the side chains of

salivarymucins.c. Fructosyltransferasesremovefructosefromsucrosetoformfructans.d. Amylaseisinvolvedinthebreakdownofstarch.

REF:Nutrients,p.16

24. ANS:aa. Correct.GCFcontainsleukocytes,95%ofwhichareneutrophils.b. GCF contains leukocytes, 95% of which are neutrophils, the remainder being lym-

phocytesandmonocytes.c. GCF contains leukocytes, 95% of which are neutrophils, the remainder being lym-

phocytesandmonocytes.d. Macrophagesareahostdefencefactorwhosemodeofactionisphagocytosis.

REF:Gingivalcrevicularfluid(GCF),p.14

25. ANS:da. A high pH which occurs during the inflammation of gingivitis and periodontitis can

affect the proportions of bacteria, especially some of the putative periodontalpathogens.

b. TheflowofGCFremovesnon-adherentmicrobialcells.c. Antibodiescaninhibitthegrowthoforalmicroorganisms.d. Correct.Theoralcavitymaintainsarelativelyconstanttemperature(35–36°C)which

providesastableconditionsuitableforthegrowthofawiderangeofmicroorganisms.

REF:Temperature,p.14


26. ANS:ca. Thepresenceof root carieswillnotnecessarily raise the temperature in aperiodontal

pocket.b. A rise in periodontal pocket temperature is not associated with a diminished flow of

GCF.c. Correct.Periodontalpocketswithactivedisease(inflammation)haveahighertempera-

ture(upto39°C)comparedwithhealthysites.d. Halitosisisnotassociatedwithariseintemperature.

REF:Temperature,p.14

27. ANS:da. Many microorganisms require a pH around neutrality for growth and are sensitive to

extremesofacidoralkali.SomeanaerobeshaveapHgrowthoptimumjustaboveneu-trality,butcannotgrowathighpHvalues.

b. Many microorganisms require a pH around neutrality for growth and are sensitive toextremesofpH.

c. Anenvironmenthighinoxygenisinhibitorytothegrowthofobligatelyanaerobicspeciesofmicroorganisms.

d. Correct. It is thedegreeofoxidation-reductionata site thatgoverns thesurvivalandrelative growth of anaerobic microorganisms. Obligate anaerobes require a low redoxpotentialforgrowth.

REF:Redoxpotential/anaerobiosis,p.15

28. ANS:aa. Correct.Oxidation-reductionlevelisusuallyexpressedastheEh.b. OxygenisonlyoneofthemanyinteractingcomponentsinfluencingtheEhofahabitat

anditsinhibitoryaction.c. pHisameasurementofacidityandalkalinity.d. Consumptionratioisnotarecognisedmeasureofoxygenreduction.

REF:Redoxpotential/anaerobiosis,p.15

29. ANS:ba. GradientsofoxygenconcentrationandEhwill exist in theoral cavity, and, therefore,

dentalplaqueissuitableforgrowthofbacteriawitharangeofoxygentolerances.b. Correct.Oralmicroorganismsareseparatedintoaerobesandanaerobesontheirability

togrowinthepresenceorabsenceofoxygen,respectively.c. Oxygenconcentrationisthemainfactorlimitingthegrowthofanaerobicbacteria.d. Bacteriathatrequirecarbondioxideforgrowtharereferredtoasbeingcapnophilic.

REF:Redoxpotential/anaerobiosis,pp.14–15

30. ANS:ba. LactobacilliprefertogrowatalowerpH.b. Correct.LactobacilliprefertogrowatalowerpH.c. LactobacilliprefertogrowatalowerpH.d. LactobacilliprefertogrowatalowerpH.

REF:pH,Figure2.4,p.14


31. ANS:ca. GCFcontainsnovelnutrients,suchasalbuminandotherhostproteinsandglycoproteins,

butdoesnotinfluencegrowthonmucosalsurfaces.b. Thepersistenceanddiversityoftheresidentoralmicrofloraisnotduetotheexogenous

factorsinthedietbutratherprimarilytothemetabolismendogenousnutrientsprovidedbythehost.

c. Correct.Thepersistenceanddiversityoftheresidentoralmicrofloraisdueprimarilytothemetabolismoftheendogenousnutrientsprovidedbythehost.

d. The persistence and diversity of the resident oral microflora is due primarily to themetabolismoftheendogenousnutrientsprovidedbythehost.

REF:Nutrients,p.16

32. ANS:ca. Nitrateingreenvegetablesmayhavesomeinfluenceonoralmicroflora.b. Dairyproducts(milk,cheese)havesomeinfluence,butarenotofmajorsignificance,on

theecologyofthemouth.c. Correct.Despitethecomplexityofthediet,fermentablecarbohydratesaretheonlyclass

ofcompoundthatmarkedlyinfluencestheecologyofthemouth.d. Xylitol is a sugar substitute that has been added to some confectionery; it cannot be

metabolisedbyoralbacteria.

REF:Nutrients,p.17

33. ANS:ba. Hydrophilicandbacterialaggregatingfactorsarechemicalpropertiesofsalivarymucins

resultingintheformationofhydrophilic,viscoelasticgels,whichfunctionasprotectivebarriersovertheoralepithelium.

b. Correct.Analternativeterminologytonon-specificandspecificfactorsisinnateimmu-nityandadaptiveimmunity.

c. Analternativeterminologytonon-specificandspecificfactors is innate immunityandadaptiveimmunity.

d. Physiochemicalandimmunologicalbarriersarepartofthehostdefencesassociatedwithoralmucosa.

REF:Hostdefences,p.17

34. ANS:ca. Microorganismsareunabletomaintainthemselvesinsalivabycelldivisionalonebecause

theyarelostatanevenfasterratebyswallowing,notchewing.b. Microorganismsareunabletomaintainthemselvesinsalivabycelldivisionalonebecause

theyarelostatanevenfasterratebyswallowing,notGCFflow.c. Correct. Microorganisms are unable to maintain themselves in saliva by cell division

alonebecausetheyarelostatanevenfasterratebyswallowing.d. Whensalivaflowisblockeditcanfacilitateashiftinoralfloraresultinginovergrowth

byGramnegativespeciesbutdoesnotaffecttheinabilityofmicroorganismstomaintainthemselvesinsalivaalone.



35. ANS:da. Defensinshaveabroadspectrumofantimicrobialactivity,notjustantifungal.b. Defensinshaveabroadspectrumofantimicrobialactivity.c. Glycolysisbyplaquebacteriacanbeinhibitedbythesalivaryperoxidaseenzymesystem,

notdefensins.d. Correct.Defensinsareafamilyofantibacterialpeptideswithabroadspectrumofanti-

bacterial,antifungalandantiviralactivity.


36. ANS:ca. Porphyromonas gingivalispreferstogrowatanalkalinepH.b. Porphyromonas gingivalispreferstogrowatanalkalinepH.c. Correct.Porphyromonas gingivalispreferstogrowatanalkalinepH.d. Porphyromonas gingivalispreferstogrowatanalkalinepH.

REF:pH,Figure2.4,pp.14–16

37. ANS:aa. Correct.SecretoryIgA(sIgA)isthemainimmunoglobulininsaliva.b. IgGisfoundinthehighestconcentrationinGCF.c. IgMisfoundinthehighestconcentrationinGCF.d. IgAisfoundinthehighestconcentrationinGCF.

REF:Saliva,pp.11–12,andGCF,pp.12–14

38. ANS:ca. Themicrofloraofidenticaltwinsismoresimilarthanthatoffraternaltwins.b. Themicrofloraofidenticaltwinsismoresimilarthanthatoffraternaltwins.c. Correct.Themicrofloraofidenticaltwinsismoresimilarthanthatoffraternaltwins,

suggestingsomegeneticinfluence.d. Themicrofloraofidenticaltwinsismoresimilarthanthatoffraternaltwins.

REF:Hostgenetics,p.21

39. ANS:ca. Toothpastescontaindetergentssuchassodiumlaurylsulphateasafoamingagentand

can lead to the reductionof salivarybacterial counts in vivo, but arenot as potent aschlorhexidine.

b. Somemouthrinses contain antimicrobial agents includingplant extracts, buthavenotproventobeaspotentaschlorhexidine.

c. Correct.Themostpotentantimicrobialagentinmouthrinsestodateischlorhexidine.d. Although fluoride does inhibit bacterial metabolism, present in most toothpastes and

someoralrinses,itsprimarybenefitisinthereductionofdentalcaries.

REF:Antimicrobialagentsandinhibitors,p.21


40. ANS:ba. Antibioticstakensystemicallyororallyforproblemsatothersitesinthebodymaycause,

afterevenafewhours,salivarymicrofloratobesuppressed,whichpermitsovergrowthbyyeasts.

b. Correct.Antibioticstakensystemicallyororallyforproblemsatothersitesinthebodymaycause,afterevena fewhours, salivarymicroflora tobesuppressed,whichpermitsovergrowthbyyeastsand/ortheemergenceofantibiotic-resistantbacteria.

c. Antibioticsgiven systemicallyororally forproblemsatother sites in thebodydonotcausethedevelopmentofacid-toleratingorganisms.

d. Histatins are a family of histidine-rich basic peptides found in human parotid andsubmandibular/sublingualglandsaliva.Antibioticstakensystemicallyororallyforprob-lemsatothersitesinthebodymaycause,afterevenafewhours,salivarymicrofloratobe suppressed permitting overgrowth by yeasts and/or the emergence of antibiotic-resistantbacteria.

REF:Antimicrobialagentsandinhibitors,pp.21–22

20

C H A P T E R 3

The Resident Oral Microflora

Multiple Choice1. In biofilms such as dental plaque, which of the following parameters forms gradients of

ecologicalsignificanceandmarkedlyaffectthedistributionofbacteria?a. Oxygentension,pHandotherfactors.b. Salivarypeptides.c. Temperature.d. Calcium.

2. Whichofthefollowingprotozoaarefoundinthemouth?a. Paramecium.b. Trichomonas tenax.c. Entamoeba histolytica.d. Giardia lamblia.

3. Classificationofmicroorganismsistheprocessofwhichofthefollowing?a. Groupingmicroorganismslogicallybasedontheirsimilaritiesanddifferences.b. Givingmicroorganismsaname.c. Developinganidentificationscheme.d. Describingthecolonialappearanceofabacterialstrain.

4. Earlyclassificationschemesreliedheavilyonwhichofthefollowing?a. Antigencharacteristics.b. Shapeofcell.c. Patternoffermentationofsimplesugars.d. Morphologicalandsimplephysiologicalcriteria.

5. Whatdoeschemotaxonomynotrelyoninprovidingabroaderanalysisofthemorecomplexcomponentsofthecell?a. Chemicalcompositionofcellwall.b. Compositionofmembranelipids.c. Wholecellproteinprofiles.d. Patternoffermentationofsimplesugars.

6. Thespeciesoforalstreptococciisolatedfromhumansincludeswhichofthefollowingfromthemutans-group?a. S. constellatus.b. S. salivarius.c. S. sobrinus.d. S. gordonii.

3—The ResidenT ORal MicROflORa 21

7. Whichofthefollowingisacommonnationalcollectionforsupplyingauthenticatedmicro-organismsforresearchpurposes?a. AmericanTypeCultureCollection.b. EuropeanCollectionofCultureTypes.c. AsianCollectionCultureCollection.d. UniversalTypeCultureCollection.

8. Usingtheculture-independentmolecularapproach,whichofthefollowingcomprisesoneofthemainstagesindeterminingthemicrobialcompositionoforalmicroflorasamples?a. DNAextraction.b. Colonycounts.c. Dispersionanddilution.d. Incubation.

9. Ofthefollowing,whichisconsideredadisadvantagetousingacultureapproachtodeter-mineoralmicrobialcomposition?a. Sensitivitytestingisnotpossible.b. Itissemi-quantitative.c. Itislabour-intensive.d. Itisquantitative.

10. Ofthefollowing identificationschemes,whichonerepresents themicrobialcharacteristicofcarbohydratefermentation?a. Acidorgasproduction.b. Aminoacidcomposition.c. Pigment,haemolysis,shapeandsize.d. Ammoniaproduction.

11. Bacterialidentificationprocesseshavebeenrevolutionisedinrecentyearsbytheadventofwhichofthefollowing?a. Chemotaxonomy.b. Determiningthegeneticrelatednessamongstrains.c. Molecularapproaches.d. Confocalmicroscopy.

12. Whichofthefollowingclassificationrepresentsacollectionofstrains?a. Subspecies.b. Typestrain.c. Species.d. Biovars.

13. StrainsofStreptococcus salivariusproducelargequantitiesofwhichexopolymerfromsucrose?a. Heteropolysaccharide.b. Fructan(inulin-structure).c. Fructan(levanstructure).d. Glycogen.

22 3—The ResidenT ORal MicROflORa

14. Bacteriathataredependantfortheirgrowthoncarbondioxidearereferredtoaswhichofthefollowing?a. Obligatelyanaerobic.b. Facultativelyanaerobic.c. Aerobic.d. Capnophilic.

15. Whichofthefollowinghasbeenisolatedfromallsitesinthemouth?a. Staphylococci.b. S. pyogenes.c. S. criceti.d. Streptococci.

16. Whichofthefollowingisthereasonforagreatinterestinmutansstreptococci?a. Theroleitplaysingingivitis.b. Theroleitplaysinperiodontitis.c. Theroleitplaysindentalcaries.d. Theroleitplaysinnecrotisingulcerativegingivitis(NUG).

17. Thenameofmutansstreptococciisderivedfromwhichofthefollowingfacts?a. Thecellspossesscellwallcarbohydrate.b. Mutansstreptococcicellscanlosetheircoccalmorphology.c. Evidenceofaserotypeofcarbohydrateantigens.d. Theycanbeexperimentallyinducedandtransmittedinanimals.

18. Mutansstreptococciarerecoveredalmostexclusivelyfromwhichofthefollowingoralsur-facesofthemouth?a. Tongue.b. Cheek.c. Teeth.d. Palate.

19. Whichofthefollowingisthemostcommonlyisolatedspeciesofmutansstreptococci?a. S. mutans.b. S. sobrinus.c. S. criceti.d. S. anginosus.

20. Which of the following is made by mutans streptococci and is associated with plaquematuration?a. Ammonia.b. Glucanandfructan.c. Lactate.d. Neuraminidase.

21. Whichofthefollowingisabacteriumthatiscapnophilic?a. Capnocytophaga gingivalis.b. Porphyromonas gingivalis.c. Fusobacterium nucleatum.d. Veillonella atypica.


22. Ofthefollowing,whichis isolatedonlyrarelyfromdiseasedsitesandisnotconsideredasignificantopportunisticpathogen?a. Streptococcus salivarius.b. Streptococcus mutans.c. Actinomyces israelii.d. Filifacter alocis.

23. WhichofthefollowingspeciesofGrampositivecocciisisolatedmainlyfromthevestibularmucosaofthehumanmouth?a. S. salivarius.b. S. gordonii.c. S. sanguinis.d. S. vestibularis.

24. Whichofthefollowingbacteriaisanimportantcauseofserious,purulentdiseaseinhumans,includingmaxillo-facialinfections?a. S. sanguinis.b. S. intermedius.c. S. gordonii.d. S. salivarius.

25. Which of the following bacteria is not routinely found in the mouths of healthyindividuals?a. S. pyogenes.b. S. salivarius.c. S. mitis.d. S. oraliss.

26. WhichofthefollowingGrampositivecoccusisgenerallyfoundintheoralcavity?a. Actinomyces.b. Anaeroglobus.c. Streptococcus.d. Neisseria.

27. Which of the following species forms a major portion of the microflora, particularly atapproximalsitesandthegingivalcrevice?a. Actinomyces israelii.b. Actinomuces meyeri.c. Actinomycesnaeslundii.d. Actinomyces radicidentis.

28. Whichofthefollowingspeciesproducescolonieswithabrownorblackpigmentonbloodagar?a. Aggregatibacterium actinomycetemcomitans.b. Porphyromonas gingivalis.c. Prevotella oralis.d. Eikenella corrodens.


29. Whichofthefollowingbacteriacanincreaseinprevalenceinadvancedcariesofbothenamelandrootsurfaces?a. Lactobacillusspecies.b. Porphyromonas gingivalis.c. Parascardovia denticolens.d. Rothia dentocariosa.

30. Cariogenicpotentialcanbedeterminedbyestimatingthenumbersofwhichofthefollowingorganisms?a. ObligatelyanaerobicGramnegativerods.b. Streptococcus anginosusgroup.c. E. faecalis.d. Lactobacilli.

31. Anincreasedleveloflactobacillicorrelatestowhichofthefollowing?a. Poororalhygiene.b. Anincreaseincarbohydrateconsumption.c. Generalhealth.d. Increasedintakeofprobioticsindairyproducts.

32. WhichofthefollowingisanaerobicorfacultativeanaerobicGramnegativecoccusthatcanbeisolatedinlownumbersfrommostsitesintheoralcavity?a. Eikenella corrodens.b. Neisseria subflava.c. Veillonella parvula.d. Capnocytophaga gingivalis.

33. Of the following, which is among the earliest colonisers of teeth, making an importantcontributiontoinitialplaqueformation?a. Veillonella parvula.b. Eikenella corrodens.c. Capnocytophagagingivalis.d. Neisseriaspecies.

34. Theperiodontalpathogenimplicatedinaparticularlyaggressiveformofperiodontaldiseaseinadolescentsiswhichofthefollowing?a. Fusobacterium nucleatum.b. Capnocytophaga gingivalis.c. Aggregatibacter actinomycetemcomitans.d. Eikenella corrodens.

35. Oralspirochaetesfallwithinwhichgenus?a. Bacteroides.b. Centipeda.c. Treponema.d. Selenomonas.


36. WhichofthefollowingcomprisesalargeproportionofthecultivableGramnegativemicro-florafoundinsubgingivaldentalplaque?a. Filofactor alocis.b. Eubacteriumspecies.c. Prevotellaspecies.d. Haemophilusspecies.

37. Whichofthefollowingstatementaboutoralspirochaetesisfalse?a. Oralspirochaetespossessperiplasmicflagella.b. Thenumbersoforalspirochaetesareraisedinadvancedperiodontaldiseases.c. Culture-independent techniques have helped to determine the diversity of oral

spirochaetes.d. The majority of oral spirochaetes can be cultured in the laboratory using advanced

anaerobictechniques.

38. AGramnegativeanaerobicbacteriumcommonlyfoundininfectedrootcanalsiswhichofthefollowing?a. Porphyromonas catoniae.b. Porphyromonas gingivalis.c. Porphyromonas endodontalis.d. Prevotella intermedia.

39. The sulphate-reducing bacteria such as methanogens contribute to which of thefollowing?a. Caries.b. Mouthodour.c. Endodonticinfections.d. Necrotisingulcerativeperiodontitis.

40. VeillonellaisananaerobicGramnegativecoccusthatplaysanimportantroleindentalplaquebywhichofthefollowingactions?a. Degradingcollagen.b. Producinghydrogensulphide.c. Penetratingunderlyingtissues.d. Convertinglactatetoweakeracids.

41. Ofthefollowing,whichrepresentstheapproximatepercentageoforganismsinplaquethatcanbeculturedinpurecultureinthelaboratory?a. 80%.b. 50%.c. 25%.d. 65%.

42. Thelargestproportionofthefungalmicroflorainthehumanmouthismadeupofwhichofthefollowing?a. Candida glabrata.b. Candida albicans.c. Candida krusei.d. Candida tropicalis.


43. WhichofthefollowingisthemostcommonsiteoforalisolationforCandida?a. Saliva.b. Dorsumofthetongue.c. Intra-oraldevicessuchasdentures.d. Plaque.

44. Bacteria belonging to the genus Mycoplasma are primarily characterised by which of thefollowingtraits?a. Thefusiformshapeofthecell.b. Theirverylargesize.c. Theirfastgrowth.d. Theabsenceofacellwall.

45. The virus most frequently encountered in saliva and the orofacial area is which of thefollowing?a. Humanpapilloma(HPV).b. Herpessimplextype1.c. Cytomegalovirus.d. Coxsackie.

Feedback1. ANS:a

a. Correct.Inbiofilmssuchasdentalplaque,gradientsdevelopinparametersofecologicalsignificance,suchasoxygentensionandpH.

b. Salivarypeptidesdonotdevelopgradientsinbiofilmsthatmarkedlyaffectthedistribu-tionofmicroorganisms.

c. Temperaturemightvaryslightly,butwouldnothaveamarkedeffectonthedistributionofmicroorganismsinthebiofilm.

d. Gradients in calcium might develop within the biofilm, but this would not markedlyaffectthedistributionofmicroorganismsinthebiofilm.

REF:Theresidentoralmicroflora(introduction),p.24

2. ANS:ba. Parameciumisanaquaticprotoan.b. Correct.T. tenaxcanbefoundinthemouth.c. E. histolyticacausesamoebicdysentery.d. G. lambliacausesgiardiasis.

REF:Protozoa,p.42

3. ANS:aa. Correct. Classification involves the grouping of microorganisms in a logical manner

basedontheirsimilaritiesanddifferences.b. Thenamingofamicroorganism(nomenclature)followstheaccurateclassificationofstrains.c. Identificationschemesaredevelopedoncethereisarobustclassificationsysteminplace.d. Describing themorphologyof colonies is onlypart of classification and identification

schemes.

REF:Principlesofmicrobialclassification,pp.25–27


4. ANS:da. Currentcharacteristicsusedinmicrobialclassificationandidentificationschemesinclude

antigencharacteristics.b. Early classification schemes reliedonmorphological criteria, such as the shapeof the

cell,butalsoneededstainingprofilesandotherphysiologicalcriteria.c. Earlyclassificationschemesreliedonsimplephysiologicalcriteria,suchasfermentation

ofsimplesugars,butalsoneededstainingprofilesandsimplemorphologicalcriteria.d. Correct.Earlyclassificationschemesreliedheavilyonbothmorphologicalandsimple

physiologicalcriteria.

REF:Theresidentoralmicroflora(introduction),p.25

5. ANS:da. Chemotaxonomy has led to major improvements in classification schemes based on

chemicalcompositionofthecellwallorwholecellproteinprofiles.b. Classificationofmembranelipidswaspartofwhatledtomajorimprovementsinclas-

sificationschemes.c. Classificationofthewholecellproteinprofileswaspartofwhatledtomajorimprove-

mentsinclassificationschemes.d. Correct.Chemotaxonomy,inwhichthereisabroaderanalysisofmorecomplexcom-

ponentsofthecellsuchasthechemicalcompositionofthecellwallorwholecellproteinprofiles,ledtomajorimprovementsinclassificationschemes.

REF:Principlesofmicrobialclassification,pp.25–26

6. ANS:ca. S. constellatusisfromtheanginosus-group.b. S. salivariusisfromthesalivarius-group.c. Correct.S. mutans,S. sobrinus,S. critcetiandS. rattiarefromthemutans-group.d. S. gordoniiisfromthemitis-group.

REF:Principlesofmicrobialclassification,Table3.3,p.26

7. ANS:aa. Correct.TypestainsareheldinnationalcollectionssuchastheAmericanTypeCulture

CollectionortheNationalCollectionofTypeCultures.b. TheEuropeanCollectionofCultureTypesisnotarecognisedcollectionformicroorganisms.c. AsianCollectionCultureCollectionisnotarecognisedtypecollection.d. UniversalTypeCultureCollectionisnotarecognisedtypecollection.

REF:Principlesofmicrobialclassification,p.27

8. ANS:aa. Correct.DNAextractionisonestageinthedeterminationofmicrobialcompositionof

microflorasamplesfromthemouthusingthemolecularapproach.b. Colonycountsareonestageinthedeterminationofmicrobialcompositionofmicroflora

samplesfromthemouthusingthecultureapproach.c. Dispersionanddilutionisoneofthestagesinculturingoralmicroorganisms.d. Incubationisoneofthestagesinculturingoralmicroorganisms.

REF:Principlesofmicrobialclassification,p.27,Figure3.2


9. ANS:ca. Antibiotic sensitivity testing is considered apositive aspectof the culture approach to

determiningthecompositionofasampleoftheoralmicroflora.b. Thecultureapproachisbothsemi-quantitativeandquantitative.c. Correct.Thelabour-intensiveaspectofthecultureapproachtodeterminingthecom-

positionofasampleoftheoralmicrofloraisconsideredadisadvantage.d. The quantitative aspect of the culture approach to determining the composition of a

sampleoftheoralmicrofloraisconsideredanadvantage.

REF:Principlesofmicrobialclassification,p.27,Figure3.2

10. ANS:aa. Correct. Acid or gas production is an example of the characteristic of carbohydrate

fermentation.b. Aminoacidcompositionisanexampleofthecharacteristicofpeptidoglycan.c. Pigment, haemolysis, shape and size are examples of the characteristic of colonial

appearance.d. Ammoniaproductionisanexampleofthecharacteristicofaminoacidhydrolysis.

REF:Principlesofmicrobialclassification,p.25,Table3.2

11. ANS:ca. Chemotaxonomyisthebroadanalysisofthecomplexcomponentsofthecellandwasa

majoradvancemanyyearsago.b. Contemporaryclassificationschemesarebasedmoreondeterminingthegeneticrelated-

nessamongstrains,butarenotarevolutionaryadvent.c. Correct.Molecularapproacheshaverevolutionisedourunderstandingofthecomplexity

anddiversityoftheresidentmicroflora.Theseapproachesalsopermittheidentificationofbacteriathatcannotbeculturedatpresent.

d. Confocalmicroscopyhasrevolutionisedourunderstandingofthestructureandarchitec-tureofbiofilms,butislessrelevanttobacterialidentification.

REF:Principlesofmicrobialclassification,p.26

12. ANS:ca. Aspeciesmaybedividedintosubspeciesifminorbutconsistentphenotypicvariations

canberecognised,butdoesnotrepresentacollectionofstrains.b. Onceaspecieshasbeenrecognised,thenatypestrainisnominatedthathasproperties

representativeofthespecies.c. Correct.Aspeciesrepresentsacollectionofstrainsthatsharemanyfeaturesincommon,

whichdifferconsiderablyfromotherstrains.d. Strainswithaspecialbiochemicalorphysiologicalpropertyaretermedbiovars,butdo

notrepresentacollectionofstrains.

REF:Principlesofmicrobialclassification,pp.26–27,Table3.3


13. ANS:ca. S. salivariusprocesslargeamountsofalevanfromsucrose,whichcontributestoitslarge

mucoidcoloniesonsucrose-containingagar.b. S. salivariusprocesslargeamountsofalevanfromsucrose,whichcontributestoitslarge

mucoidcoloniesonsucrose-containingagar.c. Correct.S. salivariusprocesslargeamountsofalevanfromsucrose,whichcontributes

toitslargemucoidcoloniesonsucrose-containingagar.d. Glycogenisanintracellularpolymer,notanexopolymer.

REF:Salivariusgroup,p.32

14. ANS:da. Obligate anaerobes require amore complexgasmixture, includinghydrogen,nitrogen

andcarbondioxide.b. Facultativelyanaerobicbacteriacangrowinthepresenceorabsenceofcarbondioxide

andothergases.c. Aerobicbacterianeedoxygenforgrowth.d. Correct.Bacteriathataredependantoncarbondioxidearetermed‘capnophilic’.

REF:Gramnegativerods,p.36[seealsop.14]

15. ANS:da. Staphylococciarenotcommonlyisolatedinlargenumbersfromtheoralcavity.b. S. pyogenesisnotusuallyisolatedfromthemouthofhealthyindividuals.c. S. cricetiisrecoveredonlyrarelyfromhumans.d. Correct.Streptococcihavebeenisolatedfromallsitesinthemouthandcomprisealarge

proportionoftheresidentcultivableoralmicroflora.

REF:Grampositivecocci:streptococcus,p.30

16. ANS:ca. Gingivitis is an inflammatory response to a non-specific proliferation of the normal

microfloraresidinginthegingivalcreviceduetopoororalhygiene.b. Periodontitisiscausedbyamicroflorawithapredominatelyanaerobicnature.c. Correct.There is a great interest in mutans streptococci because of their role in the

aetiologyofdentalcaries.d. NUGis themanifestationofunderlyingsystemicproblemsand isnotassociatedwith

mutansstreptococci.

REF:Difficultiesarisingfromrecentadvancesinmicrobialclassification,p.30


17. ANS:ba. Mutans streptococcipossesscellwallcarbohydrateantigens, lipoteichoicacid, lipopro-

teins and cellwall or cellwall-associatedproteins.Thenameof this species,however,derivesfromthefactthatcellscanlosetheircoccalmorphologyandoftenappearasshortrodsorascocco-bacilli.

b. Correct.Thenameofthisspeciesderivesfromthefactthatcellscanlosetheircoccalmorphologyandoftenappearasshortrodsorascocco-bacilli.

c. Serotypeshavebeenrecognised(a–handk)basedontheserologicalspecificityofcar-bohydrateantigens located in thecellwall.Thenameof this species,however,derivesfromthefactthatcellscanlosetheircoccalmorphologyandoftenappearasshortrodsorascocco-bacilli.

d. Littleattentionwaspaidtothisspeciesuntilthe1960swhenitwasdemonstratedthatcariescouldbeexperimentallyinducedandtransmittedinanimalswithstrainsresemblingS. mutans.

REF:Mutans-group(mutansstreptococci),pp.30–32

18. ANS:ca. Thetongueharboursmanybacterialspeciesthatplayaroleinthedevelopmentofhali-

tosis; mutans streptococci are recovered almost exclusively from non-shedding toothsurfaces.

b. Thecheekisnotasitenormallycolonisedbymutansstreptococci.c. Correct.Mutansstreptococciarerecoveredalmostexclusivelyfromhardnon-shedding

surfacesinthemouth,suchasteeth.d. Thepalatecontainskeratinisedaswellasnon-keratinisedstratifiedsquamousepithelium

whichmayinfluencetheintra-oraldistributionofsomemicroorganisms,butisnottheprimarysiteofmutanstreptococcicolonisation.

REF:Grampositivecocci,pp.30,31

19. ANS:aa. Correct.S. mutansisthemostcommonlyisolatedspeciesofmutansstreptococci.b. S. sobrinusisrecoveredfromdentalplaque,butlessfrequentlythanS. mutans.c. S. cricetiisrarelyrecoveredfromhumans.d. S. anginosus isderivedfrompurulentinfectionsfromawiderangeofsitesandisnota

memberofthemutansstreptococcusgroup.

REF:Grampositivecocci,p.31

20. ANS:ba. Mutansstreptococcicannotgenerateammoniafromarginine.b. Correct. Mutans streptococci make extracellular soluble and insoluble extracellular

polysaccharides(glucan,mutanandfructan)fromsucrosethatareassociatedwithplaquematuration.

c. Althoughlactateisanacidicfermentationproductthatisproducedbymutansstrepto-coccifromdietarysugars,itisnotassociatedwithplaquematuration.

d. Mutansstreptococcidonotproduceneuraminidase(anenzymethatremovessialicacidfromoligosaccharidesidechainsofsalivarymucins).



21. ANS:aa. Correct. The genus Capnocytophaga is capnophilic, i.e. is dependant for growth on

carbondioxide.b. P. gingivalisisobligatelyanaerobic.c. F. nucleatumisobligatelyanaerobic.d. V. atypicaisobligatelyanaerobic.

REF:Gramnegativecocci,Gramnegativerods,p.36

22. ANS:aa. Correct.S. salivarius is isolatedonlyrarelyfromdiseasedsitesandisnotconsidereda

significantopportunisticpathogen.b. S. mutansiisassociatedwithbacterialendocarditisanddentalcaries.c. A. israeliiisassociatedwithactinomycosis.d. F. alocishasbeenisolatedfromendodonticinfections.


23. ANS:da. S. salivarius is commonly isolated from most areas of the mouth, although they most

oftencolonisemucosalsurfaces,especiallythetongue.b. S. gordoniiisanearlycoloniserofthetoothsurface.c. S. sanguinisisanearlycoloniserofthetoothsurface.d. Correct.S. vestibularisisisolatedmainlyfromthevestibularmucosaofthehumanmouth.


24. ANS:ba. S. sanguinisisanormalinhabitantofthehealthyhumanmouth.b. Correct.S. intermediusisreadilyisolatedfromdentalplaqueandfrommucosalsurfaces

andisanimportantcauseofserious,purulentdiseaseinhumans,includingmaxillo-facialinfections.

c. S. gordoniiisoneoftheinitialcolonisersoftheperiodontalenvironment;generallyharm-less,itcancauseendocarditisupongainingsystemicaccess.

d. S. salivariuscolonisethemouthandupperrespiratorytractofhumansafewhoursafterbirth,makingfurtherexposuretothebacteriaharmlessinmostcircumstances.


25. ANS:aa. Correct.S. pyogenesisnotusuallyisolatedfromthemouthofhealthyindividuals.b. S. salivariusisroutinelyfoundinthemouthofhealthyindividuals.c. TwoofthemostcommonstreptococcalspeciesinthemouthareS. mitisandS. oralis.d. S. oralissisoneofthemajorearlycolonisersofdentalsurfacesinthehumanoralcavity.



26. ANS:ca. ActinomycesisaGrampositiverod.b. AnaeroglobusisaGramnegativecoccus.c. Correct.StreptococcusisaGrampositivecoccusfoundintheoralcavity.d. NeisseriaisaGramnegativecoccus.


27. ANS:ca. Actinomyces israeliicanactasanopportunisticpathogencausingachronicinflammatory

conditioncalledactinomycosis,butarenotamajorportionofthemicroflora.b. A. meyerihasbeenreportedoccasionallyandinlownumbersfromthegingivalcrevicein

healthanddisease.c. Correct.Actinomycesnaeslundiiformsamajorportionofthemicrofloraofdentalplaque,

particularlyatapproximalsitesandthegingivalcrevice.d. A. radicidentishasbeenisolatedfromendodonticinfections.

REF:Grampositiverodsandfilaments,p.34

28. ANS:ba. A. actinomycetemcomitansdoesnotgeneratebrownorblackcolonies.b. Correct.P. gingivalisproducescharacteristicallybrown/blackcoloniesonbloodagar.c. WhilesomePrevotellaspeciesproducepigmentedcolonies,P. oralisisnon-pigmenting.d. E. corrodensdoesnotproducecolonieswithabrown/blackpigment.

REF:Obligatelyanaerobicgenera,Figure3.7,pp.37–39

29. ANS:aa. Correct. Although lactobacilli usually comprise less than 1% of the total cultivable

microflora in the mouth, their proportions and prevalence increase in advanced carieslesions.

b. Porphyromonas gingivalisisassociatedwithadvancedperiodontaldisease.c. TheroleofParascardovia denticolens (formerlyB. denticolens) inthemouthisyet tobe

determined,althoughtheyareregularlyisolatedfromdentalplaque.d. Rothia dentocariosaisregularlyisolatedfromdentalplaque.


30. ANS:da. ObligatelyanaerobicGramnegativerodsareimplicatedwithperiodontaldiseases.b. Representativespeciesoftheanginosus-grouparereadilyisolatedfromdentalplaqueand

frommucosalsurfacesandareanimportantcauseofserious,purulentdiseaseinhumans,butarenotapredictorofcariogenicpotential.

c. E. faecalishasbeenspecificallyassociatedwithendodontic failuresbut isnotgenerallyassociatedwithdentalcaries.

d. Correct.Testshavebeendesignedtoprovideanindicationofthecariogenicpotentialofapatient’smouthbyestimatingthenumbersoflactobacilliinapatient’ssaliva.



31. ANS:ba. Poororalhygienecorrelatesashiftfromthestreptococci-dominatedplaqueofgingival

health to one in which Actinomyces spp., capnophilic, and obligately anaerobic Gramnegativebacteriapredominate.

b. Correct. Increased levels of lactobacilli correlate closely with the intake of dietarycarbohydrate.

c. Changesingeneralhealthandthetreatmentofdiseasecanalterthecompositionoftheoralmicroflora;increasedlactobacillilevelsarenotamongthem.

d. Lactobacillareusedasaprobiotic,buttheirusedoesnotcorrelatewithoralcolonisationbylactobacilli.


32. ANS:ba. E. corrodens is a facultative anaerobic Gram negative rod implicated in periodontal

disease.b. Correct.NeisseriaareGramnegativeaerobicorfacultativeanaerobiccoccithatareiso-

latedinlownumbersfrommostsitesintheoralcavity.c. V. parvulaisananaerobicGramnegativecoccus.d. C. gingivalisisaGramnegativerodfoundinsubgingivalplaque.

REF:Gramnegativecocci,p.36

33. ANS:da. Veillonella are strictly anaerobic Gram negative cocci playing an important role in the

ecology of dental plaque and in the aetiology of dental caries but are not earlycolonisers.

b. StrainsofE. corrodenshavebeenisolatedfromarangeoforalinfectionsincludingendo-carditisandabscesses,andhavebeenimplicatedinperiodontaldiseasebutarenotearlycolonisers.

c. Capnocytophaga is an opportunistic pathogen, isolated from a number of infections inimmunocompromisedpatients,andisnotanearlycoloniserofdentalplaque.

d. Correct.Neisseriaspeciesareamongtheearliestcolonisersofteeth,andmakeanimpor-tantcontributiontoplaqueformation,e.g.byconsumingoxygenandmakingconditionssuitableforthegrowthofanaerobicbacteria.

REF:Gramnegativecocci,p.36

34. ANS:ca. F. nucleatummakesan importantcontributiontoplaqueformation,but isnotstrongly

implicatedinaggressiveformsofperiodontaldisease.b. C. gingivalis is an opportunistic pathogen but is not strongly implicated in aggressive

formsofperiodontaldisease.c. Correct.A. actinomycetemcomitanshasbeenimplicatedinaparticularlyaggressiveform

ofperiodontaldiseaseinadolescents.d. E. corrodenshasnotbeenimplicatedinaggressiveformsofperiodontaldisease.

REF:Gramnegativerods,p.36


35. ANS:ca. OralspirochaetesfallwithinthegenusTreponema.b. OralspirochaetesfallwithinthegenusTreponema.c. Correct.OralspirochaetesfallwithinthegenusTreponema.d. OralspirochaetesfallwithinthegenusTreponema.

REF:Obligatelyanaerobicgenera,pp.37–40

36. ANS:ca. F. alocisisaGrampositiverod.b. EubacteriumspeciesareGrampositiverods.c. Correct.PrevotellaspeciesareobligatelyanaerobicGramnegativerodswhichcomprise

alargeproportionofthemicroflorafoundinsubgingivaldentalplaque.d. Haemophilus species are Gram negative facultative anaerobic rods, but they are not

particularlyassociatedwithsubgingivaldentalplaque.

REF:Obligatoryanaerobicgenera,p.37

37. ANS:da. Oralspirochaetesdopossessperiplasmicflagella.b. Thenumbersoforalspirochaetesdoincreaseinadvancedperiodontaldiseases.c. The diversity of the oral spirochaetes has been determined using culture-independent

moleculartechniques.d. Correct.Mostoralspirochaetesstillcannotbeculturedinthelaboratory,evenwiththe

useofadvancedanaerobictechniques.

REF:Obligatoryanaerobicgenera,pp.39–40

38. ANS:ca. P. catoniaeisfoundmainlyathealthysitesorinshallowpockets.b. P. gingivalisisassociatedmorewithadvancedperiodontaldisease.c. Correct.P. endodontalisiscommonlyfoundininfectedrootcanals.d. P. intermediahasbeenrecoveredmainlyfromperiodontalpockets.


39. ANS:ba. S. mutansistheprimarycauseofcaries.b. Correct.Sulphate-reducingorganisms,suchasmethanogens,producehydrogensulphide

whichcancontributetomouthodour.c. P. endodontalis and P. dentalis are found almost exclusively in infected root canals and

abscessesofendodonticorigin.d. Sulphate-reducingbacteriaarenotimplicatedinnecrotisingulcerativeperiodontitis.



40. ANS:da. T. denticola,notVeillonella,candegradecollagenandgelatine.b. Sulphate-reducingorganisms, suchasmethanogens,producehydrogensulphidewhich

cancontributetomouthodour.c. Veillonelladonotpenetrateintounderlyingtissues.d. Correct. Veillonella are anaerobic Gram negative cocci that play an important role in

dentalplaquebyconvertinglactatetoweakeracids.


41. ANS:ba. Atpresent,onlyabout50%oftheorganismsinplaquecanbeisolatedinpureculturein

thelaboratory.b. Correct.Atpresent,onlyabout50%oftheorganismsinplaquecanbeisolatedinpure

cultureinthelaboratory.c. Atpresent,onlyabout50%oftheorganismsinplaquecanbeisolatedinpureculturein

thelaboratory.d. Atpresent,onlyabout50%oftheorganismsinplaquecanbeisolatedinpureculturein

thelaboratory.

REF:Chaptersummary,p.42

42. ANS:ba. Severalyeasts,includingC. glabrata,havebeenisolatedfromthehumanmouthinsmall

quantity.b. Correct.Thelargestproportionofthefungalmicroflorainthehumanmouthismade

upofC. albicans.c. Severalyeasts,includingC. glabrata,havebeenisolatedfromthehumanmouthinsmall

quantity.d. Severalyeasts,includingC. glabrata,havebeenisolatedfromthehumanmouthinsmall

quantity.

REF:Fungi,p.40

43. ANS:ba. SalivaisthevehicleforthetransmissionofCandidaspp.tootherareasofthebody.b. Correct.Candidaisdistributedevenlythroughoutthemouthbutthemostcommonsite

ofisolationisthedorsumofthetongue.c. TheisolationofCandidaincreaseswiththepresenceofintra-oraldevicessuchasden-

tures,butthemostcommonsiteofisolationisthedorsumofthetongue.d. PlaquecanalsoharbourCandidaspp.,buttheexactproportionandsignificanceofthese

yeastsinhealthanddiseaseisunclear.

REF:Fungi,p.41


44. ANS:da. Mycoplasmas are pleomorphic; several cell shapes can occur, depending on the

environment.b. Duetotheirsmallsize(<1mm;theyarethesmallestofallfreegrowingcells)mycoplas-

masaredifficulttovisualisebynormallightmicroscopy.c. Mycoplasmaarenotoriouslyslowgrowingbacteriaandrequiresspecialisedmicrobiological

culturemedia.d. Correct.BacteriabelongingtothegenusMycoplasmaareprimarilycharacterisedthrough

theabsenceofacellwall.

REF:Mycoplasma,p.41

45. ANS:ba. Therearemorethan100typesofHPV,anumberofwhichhavebeenisolatedfromthe

oral cavity; however, the virusmost frequently encountered in saliva and the orofacialareaisHerpessimplextype1.

b. Correct.ThevirusmostfrequentlyencounteredinsalivaandtheorofacialareaisHerpessimplextype1.

c. Althoughthecytomegalovirusispresentinmostindividuals,thevirusmostfrequentlyencounteredinsalivaandtheorofacialareaisHerpessimplextype1.

d. CoxsackievirusA2,4,5,6,8,9,10and16haveallbeendetectedinsalivaandintheoral epithelium and are most often associated with hand, foot and mouth disease orherpangina.The virus most frequently encountered in saliva and the orofacial area isHerpessimplextype1.

REF:Viruses,p.41

37

C H A P T E R 4

Acquisition, Adherence, Distribution and Metabolism of the Oral Microflora

Multiple Choice1. Colonisationinvolvesmicrobespassingfrommothertochild;thiscanbedescribedaswhich

ofthefollowing?a. Transientinoculation.b. Passiveinoculation.c. Foetalinoculation.d. Familialinoculation.

2. Thedevelopingfoetusisinwhichtypeofenvironment?a. Sterile.b. Teemingwithmicrobes.c. Harboursbeneficialbacteriaonly.d. Containspioneerorganisms.

3. Which of the following has been implicated most consistently in the acquisition of andsubsequentcolonisationbymicrobesinanewborn?a. Lactobacilliinthebirthcanal.b. Yeastsinthebirthcanal.c. Salivafromthemother.d. Salivafromthefather.

4. Microbes initially transferred from mother to newborn baby include which of thefollowing?a. Eikenella corrodens.b. Mutansstreptococci.c. Streptococcus salivarius.d. Porphyromonas gingivalis.

38 4—AcquisitiOn, ADherence, DistributiOn AnD MetAbOlisM Of the OrAl MicrOflOrA

5. Based on the results of a clinical study involving infant-mother pairs, in which familymemberwouldyouexpectthegenotypeofmutansstreptococcitomatchtheonefoundinthechild?a. Mother.b. Father.c. Brothersandsisters.d. Alloftheabove.

6. Thetypeoftransmissionoforalmicrobesfrommothertochildiswhichofthefollowing?a. Horizontal.b. Vertical.c. Pioneer.d. Clonal.

7. Apioneerspeciesisdefinedaswhichofthefollowing?a. Thefirstmicroorganismstocolonise.b. Thefirstofaspeciestobenamed.c. Organismsthatsurvivedesquamation.d. OrganismsthatcanwithstandlowEh.

8. All of the following predominant organisms are present during the development of thepioneercommunityexceptwhichofthefollowing?a. S. salivarius.b. S. mitis.c. S. gordonii.d. S. oralis.

9. Which of the following activities enables a pioneer species to evade the effects of hostdefencefactors?a. IgA1proteaseactivity.b. Producingadditionalnutrients.c. Exposingnewreceptorsites.d. ChangingthelocalpH.

10. Aspioneerorganismsmature,whichofthefollowingmodificationsprovidesanenvironmentsuitableforcolonisationbyasuccessionofotherorganisms?a. Loweringtheredoxpotential.b. ReducingthelocalpH.c. Consumingtheavailablenutrients.d. Increasingtheavailabilityofoxygen.

11. Ureacanbeconvertedtowhichofthefollowing?a. Lactate.b. Acetate,formateandethanol.c. Ammoniaandcarbondioxide.d. Hydrogensulphide.

4—AcquisitiOn, ADherence, DistributiOn AnD MetAbOlisM Of the OrAl MicrOflOrA 39

12. Duringprimary tootheruption,whichof the followinggroupsoforganismsundergo thelargestincreaseindiversityandisolationfrequency?a. Grampositiveaerobicbacteria.b. Gramnegativeaerobicbacteria.c. Grampositiveobligatelyanaerobicbacteria.d. Gramnegativeobligatelyanaerobicbacteria.

13. Oral malodour is associated with high proteolytic activity; which of the following is notassociatedwithhalitosis?a. Hydrogensulphide.b. Methylmercaptan.c. Phosphoenolpyruvate.d. Dimethylsulphide.

14. Non-microbialfactorsareresponsibleforwhichofthefollowing?a. Allogenicsuccession.b. Climaxsuccession.c. Pioneermicrobialcommunity.d. Autogenicsuccession.

15. Ofthefollowingfunctions,whichdoesthelargenumberofclonalbacteriainresidenthumanmicrofloraaccomplish?a. Increasespathogenicity.b. Helpsspeciesevadethehostdefences.c. Allowsforagreaterspeciesdiversityoftheplaquecommunity.d. Ensuresspeciessurvival.

16. The increase in the prevalence of spirochaetes and black-pigmented anaerobes duringpubertyisattributedtowhichofthefollowing?a. Anincreaseinsaliva.b. Adecreaseinoralhygiene.c. Hormonesenteringthegingivalcreviceactingasnovelnutrientsources.d. Achangeindiet.

17. Thestabilityofthemicrobialcompositionandproportionovertimeisdefinedbywhichofthefollowingterms?a. Balancedecology.b. Microbialhomeostasis.c. Co-existingcomplement.d. Microbialdiversity.

18. Whichofthefollowingisnotadirecteffectofageingonoralflora?a. Achangeinsalivaryantibodies.b. Medication.c. Hormonalchanges.d. Alteredphysiologyofthemucosa.


19. TheincidenceofC. albicansisnotproportionaltoanincreaseinwhichofthefollowing?a. Age.b. Medication.c. Wearingadentalprosthesis.d. Salivaryflow.

20. Whichofthefollowingstatementsreflectstheeffectofageingontheimmuneresponse?a. Cellmediatedimmunityincreaseswithage.b. Cellmediatedimmunitydecreaseswithage.c. ActivitiesofspecificsalivaryIgMantibodiesincreasewithage.d. ActivitiesofspecificsalivaryIgGantibodiesincreasewithage.

21. WhichofthefollowingfactorsisnotlinkedtoanincreasedincidenceofCandidawithageing?a. Changestothephysiologyoftheoralmucosainoldage.b. Malnutritionandalackoftraceelementsintheelderly.c. Increasedincidenceofdenturewearinginoldage.d. Smoking.

22. Thereareanumberofchallengesindeterminingthecompositionofthemicrobialcommuni-tiesofthemouth;amongthosedifficultiesarewhichofthefollowing?a. Removingthemfromthesurfacetowhichtheyareattached.b. Removingthemduringthecorrectstageofthemicrobialcellcycle.c. Samplingthefreshestorganisms.d. Difficultiesinenumeratingthesample.

23. Anadequatemicrobialsampleiswhichofthefollowing?a. Alargeplaquesamplepooledfromdifferentsites.b. Twelve-hoursamplingtakenat1-hourincrementsforlactobacilliactivity.c. Asmallsamplefromdiscretesites.d. Mostlyfromposteriorteeth.

24. Molecularanalysisoforganismstodeterminemicrobialcommunityprofileanddiversityisbestaccomplishedwithwhichofthefollowing?a. Fluorescentin situhybridization(FISH).b. Denaturinggradientgelelectrophoresis(DGGE).c. 16SrRNA.d. DNA-DNAcheckerboard.

25. Difficulties in culturing the microflora from periodontal pockets include which of thefollowing?a. Obligateanaerobesloseviabilitywhenexposedtoair.b. Samplewillbemixedwithbloodcomponents.c. Samplewillbecontaminatedwithfooddebris.d. Thesamplepopulationwillincludemanyfacultativelyanaerobicbacteria.

26. Amoresophisticatedmethodofsamplingaperiodontalpocketincludestheuseofwhichofthefollowing?a. Periodontalprobe.b. Irrigation.c. Paperpoints.d. Abroachflushedwithgas.


27. Vortexingaplaquesamplewithglassbeadsfacilitateswhichofthefollowing?a. Disruptionoftheclumpingassociatedwiththeplaquebiofilm.b. SeparationofGramnegativefromGrampositiveorganisms.c. Maintenanceofalowredoxpotentialtofacilitateviability.d. Dilutionofthesamplepriortoplating.

28. Atpresent,whatpercentageofresidentialoralmicrofloracanbeculturedinthelaboratory?a. 10%.b. 35%.c. 50%.d. 75%.

29. Anexampleofaculturemediumdesignedtogrowthemaximumnumberofbacteriawouldbewhichofthefollowing?a. Eosinmethylenebluemedium.b. Aselectiveagar.c. Bloodagar.d. MacConkeyagar.

30. Ofthethreeassumptionsofcolonycounting,whichonemaynotbeaccurate?a. Cellsofthesamemicroorganismproducecolonieswithanidenticalmorphology.b. Cellsofdifferentspeciesproducedistinctmorphologies.c. Onecolonyarisesfromasinglecell.d. Allthreeassumptionsarecompletelyaccurate.

31. Thefirstlevelinidentificationofabacteriumiswhichofthefollowing?a. Determinetheacid-endproductprofilefollowingsugarmetabolism.b. Determinationofcellstructureusingelectronmicroscopy.c. Gramstainingandlightmicroscopy.d. Chemicalanalysisofthecellwall.

32. Which of the following is not an enzyme involved in the scavenging of oxygen or otherreactiveoxygenspeciesbyanaerobicbacteria?a. Enolase.b. Catalase.c. Superoxidedismutase.d. NADHoxidase.

33. Anon-invasivemicroscopymethodcurrentlyusedtoreconstructthefullthree-dimensionalstructureofabiofilmiswhichofthefollowing?a. Confocalmicroscopy.b. Darkfieldmicroscopy.c. Lightmicroscopy.d. Scanningelectronmicroscopy.

34. Insertingpiecesofenamelintoanintraoralprosthesisandremovingittostudyoralbiofilmsisanexampleofwhichmodelofdeterminingthecompositionoftheresidentoralmicroflora?a. Enumerationandidentification.b. Molecularapproach.c. In vivo.d. In situ.

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35. To simultaneously screen multiple clinical samples for 40 different preselected microbialspecies,whichofthefollowingmolecularapproachwouldbeselected?a. 16SrRNA.b. DGGE.c. DNA-DNAhybridisationtechnique.d. FISH.

36. Facultativeanaerobicstreptococciare thepredominantgroupofbacteria foundmostlyonwhichofthefollowingoralsurfaces?a. Dentalprostheses.b. Approximalenamelsurface.c. Cheeksandlips.d. Gingivalcrevice.

37. The predominant group of organisms recovered from the palate of healthy individualsbelongstowhichofthefollowingbacterialgenera?a. Streptococcus.b. Haemophilus.c. Prevotella.d. Veillonella.

38. Candidaaremostlikelytoberecoveredfromthepalateofwhichofthefollowing?a. Asmoker.b. Underconditionscausingxerostomia.c. Adenturewearer.d. AnHIVpatient.

39. Whichofthefollowingoralsurfacessupportsthehighestbacterialdensity?a. Cheek.b. Smoothenamelsurfaces.c. Tongue.d. Palate.

40. Oralmalodourisassociatedwithwhichofthefollowinggroupsofmicroorganisms?a. S. salivarius, S. mitus, Rothia mucilaginosa.b. Neisseria, Actinomyces, Prevotella.c. Porphyromonas, Prevotella, Fusobacteriumspp.d. V. parvula, C. gingivalis, Granulicatella.

41. Whichofthefollowingisnottrueaboutsaliva?a. Salivadoesnothaveitsownresidentbacteria.b. Saliva tests for mutans streptococci and lactobacillus form the basis of caries risk

assessment.c. Salivacontainsapproximately106bacteria/ml.d. Bacterialmultiplicationcannotoccurinsaliva.



42. Manyoftheanaerobicbacteriaisolatedfromtheperiodontalpockethavewhichofthefol-lowingtypeofmetabolism?a. Saccharolytic.b. Asaccharolyticandproteolytic.c. Capnophilic.d. Fermentative.

43. The bacterial load one would expect to find on mucosal surfaces is which of thefollowing?a. High.b. Low.c. Similartosubgingivalsites.d. Thereisnobacterialloadonmucosalsurfaces.

44. The abilities of microbes to overcome the oral removal forces include which of thefollowing?a. Pioneercolonisation.b. Succession.c. Specificadhesion.d. Transportationanddispersion.

45. The final proportions of attached microorganisms are determined by tissue tropism andwhichofthefollowing?a. TheabilitytomaintainalowEh.b. Theabilitytowithstandanoxia.c. Theabilitytoadherestrongly.d. Theabilitytogrowandcompetesuccessfullywithneighbouringbacteria.

46. BacteriasuchasStreptococcus mutanssurviveinalowpHenvironmentinbiofilmsbywhichofthefollowingstrategies?a. IncreaseintheactivityoftheirH+/ATPaseenzyme.b. Shifttoaheterofermentativemetabolism.c. Metabolismofargininetoammonia.d. RaisingthepHoptimaofglycolyticenzymes.

47. Whichofthestatementsconcerningpelliclesonoralsurfacesisnotcorrect?a. Pelliclesformonalloralsurfaces.b. Pelliclesareallidenticalincomposition.c. Thepelliclethatformsonepitheliumisthemucuscoat.d. Pellicleformationoccursassoonasacleansurfaceisexposedtosaliva.

48. Adhesinsassociatedwithsurfacestructuresonbacteriaarecalledwhichofthefollowing?a. Acquiredcementumpellicle.b. Acquiredpellicle.c. Fibrils.d. Mucuscoat.



49. Aspecificadhesinfoundinmoststreptococciiswhichofthefollowing?a. Enolase.b. AntigenI/IIfamilyofcellsurface-anchoredpolypeptides.c. Invertase.d. Fimbriae.

50. Thefunctionofcolonisationresistanceiswhichofthefollowing?a. Toprovidereceptorsforadhesion.b. Topreventattachmentbyexogenousmicroorganisms.c. Toproduceinhibitorysubstances.d. Toprovideessentialendogenousnutrients.

51. Colonisationresistancecanbeperturbedbywhichofthefollowing?a. Metabolismofendogenoussubstrates.b. Increaseintheintakeoffermentablecarbohydrates.c. Useofanalcohol-basedoralrinse.d. Long-termuseofbroadspectrumantibiotics.

52. Theneedformicrofloratobebiochemicallyflexiblestemsfromwhichofthefollowing?a. Thefluctuatingconditionsofnutrientsupply(feast-famine).b. Apathogenicrelationshipwiththehost.c. Acommensalrelationshipwiththehost.d. Nutritionaldependencyonexogenousfactors.

53. Asafactorincarbohydratemetabolism,sucroseisusedinallofthefollowingwaysexceptforwhichofthefollowing?a. Brokendownbyamylasesofsalivaryandbacterialorigin.b. Brokendownbyextracellularbacterialinvertases.c. Transportedintactasadisaccharide.d. Usedextracellularlybyglycosyltransferases.

54. Themostsignificanthighaffinitysystemoftransportingcarbohydratesacrossthecytoplas-micmembraneandintothebacterialcellbymutansstreptococciisbywhichofthefollowingprocesses?a. Phosphoenolpyruvate-mediatedphosphotransferase(PEP-PTS).b. Multiplesugarmetabolismsystem(Msm).c. Glucosepermease.d. Glucosyltransferases(GTF).

55. Underconditionsofcarbohydrateexcess,inwhatwaydobacteriareducetoxicintracellularlevelsofglycolicintermediates?a. ByusingasecondtransportsystemMsm.b. Bybindingprotein.c. Byformingglycogen.d. ViaPEP-PTS.

56. Whenandwhereareacetic,succinic,propionic,valeric,caproicandbutyricacidsfound?a. Theyareaproductofproteincatabolism.b. Theyareacidsfoundinhumanplaquesampledafterovernightfasting.c. Theyaremetabolitesfoundanhouraftertheingestionofdairycompounds.d. Theyareacidsformedfollowingtheingestionofhighconcentrationofdietarysucrose.



57. S. mutans uses sucrose to produce which of the following glucose-containingpolymers?a. Water-insolubleandsolubleglucans.b. Peptidoglycan.c. Levan.d. Inulin.

58. Highodourproducershavewhichofthefollowingbacterialprofiles?a. Lowbacterialloadonthetongue,highernumbersofGramnegativeaerobes.b. Highbacterialloadonthetongue,lownumbersofGrampositiveanaerobes.c. Higherbacterialloadonthetongue,highernumbersofGramnegativeanaerobes.d. Lowbacterialloadonthetongue,highernumbersofGrampositiveaerobes.

Feedback1. ANS:b

a. Some microorganisms are acquired only transiently but this is not truecolonisation.

b. Correct.Microbesacquiredfromthemotherispassiveinoculationofthechild.c. Foetalinoculationisnotameansofpassingmicrobesfrommothertochild.d. Familialinoculationisnotameansofpassingmicrobesfrommothertochild.

REF:Acquisitionofresidentoralmicroflora,p.45

2. ANS:aa. Correct.Thewombisnormallysterile.b. Thewombisnormallysterile.Microbialacquisitionhappensafterbirth.c. Thewombisnormallysterile.Microbialacquisitionhappensafterbirth.d. Pioneerorganismsarrivefollowingbirth.


3. ANS:ca. Lactobacilliinthebirthcanalistransient,atbest.b. Yeastinthebirthcanalistransient,atbest.c. Correct.The acquisition of microbes by a newborn happens mainly through salivary

transferfrommothertochild.d. Microbescanoccasionallybetransferredtoanewbornfromotherfamilymembers,but

itismainlyfromthemother.


4. ANS:ca. There is no evidence that E. corrodens can be transferred from mother to newborn; it

generallycoloniseslater.b. Mutansstreptococciusuallyrequiteteethtobepresentbeforetheycolonise.c. Correct.S. salivariusandsomeotherspeciesaretransferredfrommothertonewbornvia

saliva.d. P. gingivalisdoesnotnormallycolonisethemouthuntilaftertootheruption.




5. ANS:aa. Correct. In the majority of infant-mother pairs examined, the genotype of mutans

streptococciinthemothermatchedtheonefoundinthechild.b. Littleevidenceoffather-infanttransmissionofmutansstreptococciwasobserved.c. Strainsofsomebacteriacanbeacquiredoccasionallybyyoungchildrenfromotherfamily

members.d. Thegenotypesofmutansstreptococcifoundinchildrenweregenerallyidenticaltothose

oftheirmothers.


6. ANS:ba. Horizontaltransmissionoccursbetweenspouses.b. Correct.Transmissionfrommothertoinfantisvertical.c. Pioneerisnotaformoftransmissionbutsuccession.d. Clonalreferstoamicrobe’sorigins,notamodeoftransmission.


7. ANS:aa. Correct.Thefirstmicroorganismstocolonisearecalledpioneerspecies.Collectivelythey

makeupthepioneermicrobialcommunity.b. Thefirstmicroorganismstocolonisearecalledpioneerspecies.c. Desquamation is oneof thephysical environmental resistance factors limitingpioneer

communitygrowth.d. Eh(redoxpotential)isoneofthelocalenvironmentalfactorslimitingpioneercommunity

growth.


8. ANS:ca. S. salivarius, S. mitis and S. oralis are the particular predominant cultivable organisms

presentduringthedevelopmentofthepioneercommunity.b. S. salivarius, S. mitis and S. oralis are the particular predominant cultivable organisms

presentduringthedevelopmentofthepioneercommunity.c. Correct.S. gordoniiisnotapredominantstreptococcuspresentduringtheinitialpioneer

colonisation;itismorepresentseveralmonthsafterbirth.d. S. salivarius, S. mitis and S. oralis are the particular predominant cultivable organisms

presentduringthedevelopmentofthepioneercommunity.

REF:Pioneercommunityandmicrobialsuccession,pp.46–47



9. ANS:aa. Correct.ManyofthepioneerspeciespossessIgA1proteaseactivity,whichmayenable

producerorganismstoevadetheeffectsofthiskeyhostdefencefactor.b. Producingadditionalnutrientsaddressesthewayinwhichpioneercommunitiesareable

toinfluencethepatternofmicrobialsuccession.c. Exposingnewreceptorsitesaddressesthewayinwhichpioneercommunitiesareableto

influencethepatternofmicrobialsuccession.d. Changing the local pH addresses the way in which pioneer communities are able to

influencethepatternofmicrobialsuccession.


10. ANS:aa. Correct. Lowering the redox potential encourages bacterial succession, especially by

obligatelyanaerobicbacteria.b. ReducingthelocalpHmayreducethenumberofpioneerspeciesabletocolonise.c. Consumingadditionalnutrientsmayreducethepatternofmicrobialsuccession.d. Increasingoxygenlevelswouldrestrictthepatternofmicrobialsuccession,especiallyby

inhibitingthegrowthofobligateanaerobes.


11. ANS:ca. Lactateisaproductofcarbohydratemetabolism.b. Acetate,formateandethanolareproductsofcarbohydratemetabolism.c. Correct.Ureacanbeconvertedbysomeoralbacteriatoammoniaandcarbondioxide.d. Hydrogensulphideisaproductofthemetabolismofsulphur-containingcompounds.

REF:Nitrogenmetabolism,p.69

12. ANS:da. Gramnegativeobligatelyanaerobicbacteriaareisolatedmorecommonlyduringprimary

tootheruption.b. Gramnegativeobligatelyanaerobicbacteriaareisolatedmorecommonlyduringprimary

tootheruption.c. Gramnegativeobligatelyanaerobicbacteriaareisolatedmorecommonlyduringprimary

tootheruption.d. Correct.Gramnegativeobligatelyanaerobicbacteriaareisolatedmorecommonly,and

agreaterdiversityofspeciesisrecoveredfromaroundthegingivalmarginofthenewlyeruptedteeth.




13. ANS:ca. Halitosisisassociatedwiththeproductionofvolatilesulphurcompoundssuchashydro-

gensulphide.b. Halitosisisassociatedwiththeproductionofvolatilesulphurcompoundssuchasmethyl

mercaptan.c. Correct. Phosphoenolpyruvate is a glycolytic intermediate and not associated with

halitosis.d. Halitosisisassociatedwiththeproductionofvolatilesulphurcompoundssuchasdime-

thylsulphide.

REF:Oralmalodour(halitosis),p.71

14. ANS:aa. Correct.Factorsofnon-microbialoriginareresponsibleforanalteredpatternofcom-

munity development in allogenic succession. For example, tooth eruption significantlyaltersthemicrobialsuccessionoforganisms,aswillanewlyinserteddenture,removableorthodonticapplianceoranacrylicobturator.

b. Aclimaxsuccessionisaprocessinthedevelopmentofamicrobialcommunity.c. Apioneermicrobialcommunityisthecollectionoftheearliestcolonisers.d. Autogenicsuccessioniswhencommunitydevelopmentisinfluencedbymicrobialfactors;

forexample,theincreaseisnumberanddiversityofobligateanaerobesinbiofilmsisduetotheutilisationofoxygenbypioneerspecies.

REF:Allogenicandautogenicmicrobialsuccession,pp.47–49

15. ANS:ba. Relatively few clones are found within species of pathogenic bacteria, and a limited

numberofthesemayberesponsibleforthemajorityofinfections.b. Correct.Residenthumanmicrofloragenerallydisplaylargenumbersofclones,andthis

maybeastrategytohelpsuchspeciesevadethehostdefences.c. Havingalargenumberofclonalbacteriainresidenthumanmicrofloradoesnotaddress

speciesdiversity.d. Havinga largenumberofclonalbacteria inresidenthumanmicrofloradoesnotalone

ensurespeciessurvival;theclonalaspectalonedoesnotassuresurvival.


16. ANS:ca. Hormones entering the gingival crevice acting as novel nutrient sources increase the

prevalenceofspirochaetesandblack-pigmentedanaerobesduringpuberty.b. Hormones entering the gingival crevice acting as novel nutrient sources increase the

prevalenceofspirochaetesandblack-pigmentedanaerobesduringpuberty.c. Correct. Following tooth eruption, the isolation frequency of spirochaetes and black-

pigmented anaerobes increases. The increased prevalence of spirochaetes and black-pigmented anaerobesduringpubertymightbedue tohormones entering thegingivalcreviceandactingasanovelnutrientsource.

d. Hormones entering the gingival crevice acting as novel nutrient sources increase theprevalenceofspirochaetesandblack-pigmentedanaerobesduringpuberty.

REF:Ageingandtheoralmicroflora,p.49



17. ANS:ba. Balancedecologyspeakstotheenvironmentinwhichthemicrobialcommunitylives,not

ofitsstabilityorlackthereof.b. Correct.Microbialhomoeostasisinadultsoccurswhenthecompositionandproportions

oftheresidentoralmicrofloraremainreasonablystableovertimeandcoexistinrelativeharmonywiththehost.

c. Co-existingcomplementisnotarecognisedterm.d. Microbialdiversitymayormaynotbepartofthestablepatternofaspecificmicrobialcom-

munity.Itisatermthatspeakstothecompositionandnottothestateorstatusofthegroup.


18. ANS:ba. Adirecteffectofageingonoralfloraincludesachangeinsalivaryantibodies.b. Correct.Medicationisanindirecteffectorofageingontheoralmicroflora.c. Adirecteffectofageingonoralfloraincludeshormonalchanges.d. Adirecteffectofageingonoralfloraincludesalteredphysiologyofthemucosa.


19. ANS:da. TheincidenceofC. albicansincreaseswithage.b. TheincidenceofC. albicansincreaseswithmedicationuse.c. TheincidenceofC. albicansincreaseswithwearingadentalprosthesis.d. Correct.TheincidenceofC. albicansdoesnotincreasewithsalivaryflow.


20. ANS:ba. Cellmediatedimmunitydecreaseswithage.b. Correct.Cellmediatedimmunitydecreaseswithage.c. ActivitiesofspecificIgMantibodiesdecreaseintheelderly.d. ActivitiesofspecificIgGantibodiesdecreaseintheelderly.


21. ANS:da. Theincidenceoforalcandidosisismorecommonintheelderlyandthishasbeenattrib-

utednotonly to the increased likelihoodofdenturewearingbut also tophysiologicalchangesintheoralmucosa,malnutritionandtraceelementdeficiencies.

b. Theincidenceoforalcandidosisismorecommonintheelderlyandthishasbeenattrib-utednotonly to the increased likelihoodofdenturewearingbut also tophysiologicalchangesintheoralmucosa,malnutritionandtraceelementdeficiencies.

c. Theincidenceoforalcandidosisismorecommonintheelderlyandthishasbeenattrib-utednotonly to the increased likelihoodofdenturewearingbut also tophysiologicalchangesintheoralmucosa,malnutritionandtraceelementdeficiencies.

d. Correct.Smokinghasbeenshowntoaffectbacterialcountsandisasignificantriskfactorforperiodontaldiseasesbutisnotspecificallylinkedtooralcandidosis.




22. ANS:aa. Correct.Thereareanumberofchallengeswhenattemptingtodeterminethecomposi-

tion of the microbial communities at sites in the mouth.These range from the basicproblemof removing themajorityof themicroorganisms from theirhabitat (manyofwhicharebynecessityboundtenaciouslytoasurfaceortoeachother,andthesitemaybedifficulttoaccess)totheireventualidentification.

b. Thestageinthecellcycleofthemicrobesisnotimportanttosamplecollection.c. Sampling‘old’or‘new’plaqueisnotaparticularchallenge.d. Enumeratingthepopulationsampledispartoftheidentificationprocess.

REF:Methodsofdeterminingthecompositionof theresidentoralmicroflora,Table4.3,pp.50–51

23. ANS:ca. Largeplaquesamplesfromdifferentsitescanbeoflittlevaluebecauseimportantsite-

specificdifferenceswillbeobscured.b. Lactobacilli activity canbemonitored; this isnot a samplemethodbut aprotocol for

assessmentofcariesrisk.c. Correct.Themicrofloracanvaryincompositionoverrelativelysmalldistances.Therefore,

largeplaquesamplesoranumberofsmallerpooledsamplesfromdifferentsitescanbeoflittlevaluebecauseimportantsite-specificdifferenceswillbeobscured.Consequently,smallsamplesfromdiscretesitesarepreferable.

d. Samplescanbetakenfromanyteeth;theyshouldalwaysbeassmallasisfeasiblefromdiscretesites.

REF:Methodsofdeterminingthecompositionoftheresidentoralmicroflora,Figure4.4,pp.50–51

24. ANS:ba. FISHlooksatcommunitystructure.b. Correct.DGGEcanbeused for communityprofilingandestimating thediversityof

themicrobialcommunity.c. 16SrRNAisusedforgeneamplificationandmicrobialidentification.d. DNA-DNAcheckerboarddetectspreselectedmicroorganisms.

REF:Methodsofdeterminingthecompositionoftheresidentoralmicroflora,Figure4.4,pp.50–51

25. ANS:aa. Correct.Highnumbersofobligatelyanaerobicbacteriaarefoundinthegingivalcrevice

andperiodontalpocket,mostofwhichwilllosetheirviabilityifexposedtoair.b. Thesamplemayormaynotbemixedwithbloodcomponentsbutitisnotadifficulty

intheculturingprocess.c. Thepresenceoffooddebriswillnotimpactthecultureprocess.d. Facultativelyanaerobicbacteriaarenotdifficulttogrowinthelaboratory.

REF:Methodsofdeterminingthecompositionoftheresidentoralmicroflora,Table4.3,p.50–52



26. ANS:da. Aperiodontalprobewouldnotbeanidealcollectioninstrument.b. Irrigationisnotasophisticatedcollectionmethod.c. A common approach is to insert paper points into pockets but the number of firmly

adherentorganismsremovedfromtherootofthetoothwillbesmall.d. Correct. A particularly sophisticated method employs a broach kept withdrawn in a

cannulathatisflushedconstantlywithoxygen-freenitrogen.Aftersamplingatornearthebaseofthepocket,thebroachisretractedintothecannulaandwithdrawn.

REF:Methodsofdeterminingthecompositionoftheresidentoralmicroflora,p.52

27. ANS:aa. Correct.Oneofthemostefficientmethodsensuringasinglelayerofcellsinasample,

particularly for subgingival plaque, is to vortex sampleswith small, sterile glass beads,ideallyinatubefilledwithinertgas.

b. VortexingdoesnotseparateGramnegativefromGrampositiveorganisms.c. Speciallydesignedtransportfluidscontainingreducingagents,notvortexing,maintaina

low redox potential to help reduce the loss of viability of anaerobic organisms duringdeliverytothelaboratory.

d. Samplesaredilutedinthecultivationnotdispersionprocess.


28. ANS:ca. At present only about 50% of the resident oral microflora can be cultured in the

laboratory.b. At present only about 50% of the resident oral microflora can be cultured in the

laboratory.c. Correct.Atpresentonlyabout50%of theresidentoralmicrofloracanbecultured in

thelaboratory.d. At present only about 50% of the resident oral microflora can be cultured in the

laboratory.


29. ANS:ca. EosinmethylenebluecontainsdyestoxicforGrampositivebacteriaandbilesaltstoxic

toGramnegativebacteriaandisaselectiveanddifferentialmediumforcoliforms.b. Aselectivemediumisdesignedtogrowonlyalimitednumberofspecies.c. Correct.Bloodagarisanexampleofaculturemediumdesignedtogrowthemaximum

numberofbacteria.d. MacConkeyagarisaselectivemediumusedtocultureGramnegativeentericbacteria.




30. ANS:ca. Generally,theassumptionholdstruethatcellsofthesamemicroorganismproducecolo-

nieswithanidenticalmorphology.b. Generally, the assumption holds true that cells of different species produce distinct

morphologies.c. Correct.Generally,theseassumptionsholdtrueexceptthatmostcoloniesinevitablyarise

from small aggregates of cells, not a single cell; this emphasises the need for efficientdispersionofsamples.

d.Onlythefirsttwoassumptionsaregenerallyaccurate.


31. ANS:ca. Somebacteriadorequireamoresophisticatedapproachsuchastheapplicationofgas–

liquidchromatographytodeterminetheiracidend-productsofmetabolism;however,itisnotthefirstlevelintheenumerationandidentificationprocess.

b. Electronmicroscopycanbeusedlatertodeterminethefinestructureofabacterialcell.c. Correct.ThefirstlevelofdiscriminationinvolvestheGramstainingofsubculturedcolo-

nies.ThisprovidesevidenceastowhethertheorganismisGrampositiveorGramnega-tiveandprovidesinformationoncellmorphology.

d. Chemicalanalysisof thebacterialcellwall isa sophisticatedapproachapplied toonlycertaingroupsofmicro-organisms.


32. ANS:aa. Correct.Enolaseisanenzymeinvolvedinglycolysis.b. Catalaseisusedtoscavengehydrogenperoxidebysomebacteria.c. Superoxidedismutaseisusedtoscavengeoxygenradicalsbysomebacteria.d. NADHoxidaseisusedtoscavengeoxygenbysomebacteria.

REF:Oxygenmetabolism,p.70.

33. ANS:aa. Correct.Non-invasive techniques suchas confocal laser scanningmicroscopyarecur-

rentlyused,withandwithouttheuseofspecificprobes(antibodyoroligonucleotide),todeterminethetruearchitectureofplaqueandthelocationofselectedbacteriawithinthebiofilm.

b. Darkfieldmicroscopyhasbeenusedtoquantifythenumbersofmotilebacteria(includingspirochaetes)directlyindentalplaque(particularlyfromsubgingivalsites).

c. Lightmicroscopydoesnotgiveafull3-Dstructureofbiofilms.d. Electronmicroscopyrequiressamplestobeprocessedbeforeviewingwhichcandistort

thestructureofbiofilms.




34. ANS:da. Enumerationandidentification involvescountingmicrobialcolonies.Theprosthesis is

anexampleofanin situmodeltofacilitatesampling.b. Amolecularapproachisinvolvedinexaminingsamples.Theprosthesisisanexampleof

anin situmodeltofacilitatesampling.c. In vivomeanswithintheliving,e.g.usinghumanoranimalsamples.Aprosthesiswould

moreappropriatelybenamedanin situmethod,meaning‘intheplace’.d. Correct.Theprosthesismethodofsamplingwouldbeanin situmodel.

REF:Methodsofdeterminingthecompositionoftheresidentoralmicroflora,pp.53–54

35. ANS:ca. 16SrRNAgenesequenceshaveenabledtherecognitioninclinicalspecimensofspecies

thatareasyetunculturableinthelaboratory.b. DGGEisused tocompare thediversityoforalmicrobial communities fromdifferent

sitesinhealthanddisease.c. Correct.DNA-DNAhybridisationtechniqueisusedtosimultaneouslyscreenmultiple

clinicalsamplesfor40differentpreselectedmicrobialspecies.d. FISHexaminesthecommunitystructure.


36. ANS:ca. Dentalprostheseswillpresentwithahostofintraoralmicrobes.b. Approximalsurfacessupportadiversemicrofloraincludingmanyanaerobes.c. Correct.Cheeksandlipshousemostlyfacultativeanaerobes,suchasstreptococci.d. Gingivalcreviceprovidesasitewhichsupportsadiversemicroflora, includingobligate

anaerobes.

REF:Distributionoftheresidentoralmicroflora,Figure4.5,pp.54–55

37. ANS:aa. Correct.Themicrofloraofthenormalpalatecanshowlargevariationsbetweensubjects,

notonly in the totalcolony formingunits removed,butalso in theproportionsof theindividualspecies.Themajorityofthebacteriarecoveredarestreptococci.

b. HaemophiliandGramnegativeanaerobesarealsoregularlyrecoveredbutatlowlevels.c. Themajorityofthebacteriarecoveredarestreptococci.d. Themajorityofthebacteriarecoveredarestreptococci.

REF:Distributionoftheresidentoralmicroflora,pp.54–55

38. ANS:ca. SmokingisnotadirectcontributingfactortothegrowthofCandida.b. XerostomiaisnotacontributingfactortoCandidagrowth.c. Correct.Candidaarenotregularlyisolatedfromthenormalpalateexceptwhendentures

areworn;inthissituation,themucosaofthepalatecanbecomeinfectedwithC. albicans.d. CandidaisanopportunisticorganismfoundinHIVpositivepatients;however,thepalate

isnotatypicalsiteforcolonisation.

REF:Distributionoftheresidentoralmicroflora,p.55



39. ANS:ca. Thedorsumof the tonguesupportsahigherbacterialdensity thanotheroral surfaces

suchasthebuccalmucosa.b. Thedorsumof the tonguesupportsahigherbacterialdensity thanotheroral surfaces

suchassmoothsurfacesonteeth.c. Correct.Thedorsumofthetonguewithitshighlypapillatedsurfacehasalargesurface

areaandsupportsahigherbacterialdensityandamorediversemicroflorathanotheroralmucosalsurfaces.

d. Thepalatehasalowbacterialdensity.

REF:Distributionoftheresidentoralmicroflora,pp.55–58

40. ANS:ca. Ahigherbacterialload,especiallyofGramnegativeanaerobes(includingPorphyromonas,

PrevotellaandFusobacteriumspp.),wasisolatedfromthetonguesofsubjectswithhighodour.

b. Ahigherbacterialload,especiallyofGramnegativeanaerobes(includingPorphyromonas, PrevotellaandFusobacteriumspp.),wasisolatedfromthetonguesofsubjectswithhighodour.

c. Correct. Oral malodour is associated with the microflora of the tongue. A higherbacterial load, especially of Gram negative anaerobes (including Porphyromonas, PrevotellaandFusobacteriumspp.),wasisolatedfromthetonguesofsubjectswithhighodour.

d. Ahigherbacterialload,especiallyofGramnegativeanaerobes(includingPorphyromonas, PrevotellaandFusobacteriumspp.),wasisolatedfromthetonguesofsubjectswithhighodour.


41. ANS:ca. Althoughsalivacontainsupto108microorganisms/ml,itisnotconsideredtohaveits

ownresidentmicroflora.b. Thelevelofmutansstreptococciand/orlactobacillihasbeenusedasanindicatorofthe

caries susceptibility of an individual, and kits for their culture are commerciallyavailable.

c. Correct.Salivacontainsabout108bacteria/ml.d. Thenormalrateofswallowingensuresthatbacteriacannotbemaintainedinthemouth

bymultiplicationinsaliva.


42. ANS:ba. Saccharolyticmetabolisminvolvesthebreakdownofcarbohydrates.b. Correct.Manyoftheanaerobicbacteriaisolatedfromtheperiodontalpocketgaintheir

energyfromthebreakdownofhostproteins,andthisisreferredtoasbeingasaccharolyticandproteolyic.

c. Capnophilic refers to the fact that some bacteria require carbon dioxide forgrowth.

d. Fermentationinvolvesthebreakdownofcarbohydrates.

REF:Nitrogenmetabolism,p.69



43. ANS:ba. Duetodesquamation,thebacterialloadonmucosalsurfacesislow.b. Correct.Duetodesquamation,thebacterialloadonmucosalsurfacesislow.c. Subgingivalsurfaceshaveahighbacterialload.d. Allmucosalsurfaceshavelowmicrobialloads.


44. ANS:ca. Pioneercoloniesarethefirsttocoloniseontoothsurfacesandnotacharacteristicofmicrobes.b. Succession refers to the increase incomplexityof themicrobial communityover time,

fromsinglespeciestoadiversegroupofinteractingmicroorganisms,anddoesnotrefertotheabilitytoovercomeremovalforces.

c. Correct.Forsuccessfulcolonisation,microorganismsmustfirstadheretoasurfaceandthenbeabletomultiply.Inordertoovercometheoralremovalforces,microbeseitherseek out habitats that offer protection (refuge) from the environment, or they deployspecificadherencemechanisms.Thedistributionofmanyoralpopulationsisrelatedtotheirabilitytoadheretospecificsurfaces.

d. Transportationanddispersiondonotimpacttheabilitytowithstandoralremovalforces.

REF:Factorsinfluencingthedistributionoforalmicroorganisms,p.59

45. ANS:da. Thedegreeofanaerobiosis (redoxpotential;Eh)andnutrientavailabilitywilldetermine

whethertheattachedcellscangrowatasite.ThesiteswiththelowestEh(andthehighestnumberofobligateanaerobes)arethoseassociatedwithstagnantareasontheteeth.

b. Indentalplaque,oxygenconsumptionbyaerobicandfacultativelyanaerobicorganismscancreateanoxic (oxygen-depleted)conditionswhichwillalso facilitate thegrowthofobligateanaerobes.

c. Theabilitytoadherestronglyisafactorinovercomingforcesoforalremoval.d. Correct. The final proportions of attached microorganisms are determined by their

subsequentabilitytogrowandcompetesuccessfullywithneighbouringspecies.

REF:Factorsinfluencingthedistributionoforalmicroorganisms,p.59

46. ANS:aa. Correct. Streptococcus mutans increases the activity of H+/ATPase system to remove

protonsfrominsidethecell.b. S. mutansshiftstoahomofermentativemetabolism.c. S. mutans,unlikesomeotherstreptococci,cannotmetabolisearginine.d. S. mutanswouldlowerthepHoptimaofglycolyticenzymes.

REF:Acidtolerance,p.66

47. ANS:ba. Pellicleformsonalloralsurfaces,butisnotidentical.b. Correct.Thecompositionofthepelliclethatformsonalloralsurfacesisnotidentical.c. Thepelliclethatformsonepitheliumisthemucuscoat.d. Pellicleformationoccursassoonasacleansurfaceisexposedtosaliva.

REF:Hostandbacterialfactorsinvolvedinadherence,p.60



48. ANS:ca. Pelliclescontainhostreceptors,notbacterialadhesins.b. Pelliclescontainhostreceptors,notbacterialadhesins.c. Correct.Oftenadhesinsareassociatedwithsurfacestructurestermedfibrilsorfimbriae.

Fibrilsareshortandnarrowwhilefimbriaehaveameasurablewidth(3–14nm)andavariablelengthupto20mm.

d. Mucuscoatisanalternativetermforthepelliclethatformsontheepithelialsurface.

REF:Hostandbacterialfactorsinvolvedinadherence,pp.60–61

49. ANS:ba. Enolaseisanenzymeinvolvedinglycolysis.b. Correct.AsignificantadhesinistheantigenI/IIfamilyofcellsurface-anchoredpolypep-

tidesfoundinmostoralstreptococci.c. Invertaseisanenzymeinvolvedinthemetabolismofsucrose.d. The presence of fimbriae greatly enhances the bacteria’s ability to attach to the host;

however,aspecificadhesinfoundinmoststreptococciistheantigenI/IIfamilyofcellsurface-anchoredpolypeptides.

REF:Hostandbacterialfactorsinvolvedinadherence,p.61

50. ANS:ba. Functionsof residentoralmicroflora that contribute to colonisation resistance include

competitionforreceptorsforadhesion,notprovisionofreceptors.b. Correct.Colonisationresistanceinvolvestheresidentmicroflorafrompreventingcolo-

nisationbyexogenousmicroorganisms.c. Theproductionofinhibitorysubstancesisoneofthemechanismsbywhichtheresident

microflorapreventscolonisationandgrowthofexogenousmicroorganisms.d. Colonisationresistancedoesnot involvetheprovisionofendogenousnutrients for the

growthofexogenousspecies.

REF:Functionsoftheclimaxcommunity:colonisationresistance,p.62

51. ANS:da. Metabolismofendogenoussubstrates is themeansbywhichbacteriareceivenutrients

fromthehost.b. Increaseintheintakeoffermentablecarbohydratescouldtipthebalanceoftheresident

microflora,butitisnotlikelytoaffectcolonisationresistance.c. The use of an alcohol-based oral rinse has not demonstrated colonisation resistance

impairment.d. Correct.Long-termuseofbroadspectrumantibioticscanreducetheresidentmicroflora

andtherebyimpaircolonisationresistance.

REF:Functionsoftheclimaxcommunity:colonisationresistance,pp.61–63



52. ANS:aa. Correct.Thefluctuatingconditionsofnutrientsupply(feast–famine)andenvironmental

changerequiretheoralmicrofloratopossessbiochemicalflexibility.b. Thepatternofmetabolismiscloselyrelatedtowhethertheresidentmicrofloraenjoysa

pathogenicorcommensalrelationshipwiththehost.c. Thepatternofmetabolismiscloselyrelatedtowhethertheresidentmicrofloraenjoysa

pathogenicorcommensalrelationshipwiththehost.d. Nutrientsarederivedmainlyfromthemetabolismofendogenoussubstratespresentin

salivaandgingivalcrevicularfluid(GCF),andtheseoftenrequiretheconcertedactionofconsortiaofmicroorganisms.

REF:Metabolismoforalbacteria,p.63

53. ANS:aa. Correct.Starchesandnotsucrosearebrokendownbyamylasesofsalivaryandbacterial

origin.b. Sucrosecanbebrokendownbyextracellularbacterialinvertases.c. Sucrosecanbetransportedintactasadisaccharide.d. Sucrosecanbeusedextracellularlybyglycosyltransferases.

REF:Metabolismoforalbacteria,pp.63–64

54. ANS:aa. Correct.The most significant system is the phosphoenolpyruvate–phosphotransferase

system (PEP-PTS), which is the high-affinity sugar transport system for mono- anddisaccharidesinmutansstreptococci.

b. TheMsmisoneofthetransportmechanisms,butnotthemostsignificantone.c. Glucosepermeaseisoneofthetransportmechanisms,butnotthemostsignificantone.d. GTFareinvolvedinthesynthesisofglucans.


55. ANS:ca. TheMsmiscapableoftransportingvariouscommonsugarsincludingsucrose,melibiose,

raffinoseandmaltose(aderivativeofstarch).b. Bindingproteinwillnotreducetoxicintracellularlevelsofglycolicintermediates.c. Correct. Under conditions of carbohydrate excess, bacteria reduce toxic intracellular

levelsofglycolicintermediatesbyformingglycogen.d. ThePEP-PTSisahighaffinitysugartransportsystemthatisrepressedunderhighsugar

concentrations.




56. ANS:ba. Acetic,succinic,propionic,valeric,caproicandbutyricacidsarefoundinhumanplaque

sampledafterovernightfasting.b. Correct.Acetic,succinic,propionic,valeric,caproicandbutyricacidsarefoundinhuman

plaquesampledafterovernightfasting.c. Acetic,succinic,propionic,valeric,caproicandbutyricacidsarefoundinhumanplaque

sampledafterovernightfasting.d. Lacticacidisthemainendproductformedfollowingtheingestionofhighconcentrations

ofsucrose.


57. ANS:aa. Correct.S. mutansusessucrosetoproducewater-insolubleandsolubleglucans,which

arepolymersofglucose.b. Peptidoglycanisacellwallcomponentwithacomplexstructure.c. Levansareapolymeroffructose.d. Inulinisapolymeroffructose.


58. ANS:ca. Highodourproducershavehigherbacterialloadonthetongueandhighernumbersof

Gramnegativeanaerobes.b. Highodourproducershavehigherbacterialloadonthetongueandhighernumbersof

Gramnegativeanaerobes.c. Correct. High odour producers have higher bacterial load on the tongue and higher

numbersofGramnegativeanaerobes.d. Highodourproducershavehigherbacterialloadonthetongueandhighernumbersof

Gramnegativeanaerobes.



59

C H A P T E R 5

Dental Plaque

Multiple Choice1. Which of the following is the general term for the complex microbial community that

developsonthetoothsurface?a. Calculus.b. Saliva.c. Dentalplaque.d. Dentalstain.

2. Dentalplaqueisanexampleofwhichofthefollowing?a. Pellicle.b. Biofilm.c. Salivarymucin.d. Planktoniccommunity.

3. Whichofthefollowingisapropertyofbiofilmsandisofclinicalsignificance?a. Facilitatestainformation.b. Increasesensitivitytoantibiotics.c. Extremelytolerantofantimicrobialagents.d. Enhancethedevelopmentofhalitosis.

4. Whichofthefollowingisageneralpropertyofbiofilms?a. Susceptibletohostdefences.b. Limitedhabitatrange.c. Openarchitecture.d. Reducedvirulence.

5. Whichofthefollowingisacomponentthatisnotpresentintheacquiredenamelpellicle?a. Glucan.b. Proline-richpeptides.c. Glucosyltransferases.d. Enolase.

6. Theformationofpelliclestartshowlongafteracleantoothsurfaceisexposedtotheoralenvironment?a. Aftertheattachmentofpioneerbacteria.b. Within90–120minutes.c. Assoonasthetoothsurfaceiscleaned(withinseconds).d. After>2hours.


60 5—Dental Plaque

7. Which of the following is true about how the majority of microorganisms are generallytransportedtothetoothsurface?a. Carriedbyfoodparticles.b. Salivaryflow.c. Toothbrushing.d. Bacterialmotility.

8. The weak physicochemical interactions that facilitate bacterial adhesion to the acquiredpelliclemaybecomeirreversibleduetowhichofthefollowing?a. Interactiveenergy.b. Hydrophobicity.c. Highionicstrength.d. Adhesin-receptorinteractions.

9. Whichof the followingorganisms attach to a clean enamel surface aspioneer species ofbacteriainthedevelopmentofdentalplaque?a. Coccal.b. Rodshaped.c. Filamentshaped.d. Spiralshaped.

10. Whichofthefollowingtermsdescribeshiddenreceptorsforbacterialadhesins?a. Glucan.b. Fimbriae.c. Cryptitopes.d. Fibrinogen.

11. The process by which plaque microflora becomes more diverse over time is described bywhichofthefollowing?a. Microbialsuccession.b. Aggregation.c. Adhesin.d. Desquamation.

12. Pioneerspeciesinteractdirectlywiththeacquiredpelliclewhilesubsequentbiofilmforma-tionisdependantonwhichofthefollowing?a. Intergenericcoadhesion.b. Electrostaticattractiveforces.c. Abilitytoactivelydetach.d. Gradientformation.

13. Ofthefollowing,whichtermdescribestheabilityofindividualbacterialcellstobeabletocommunicatewith,andrespondto,neighbouringcells?a. Genetransfer.b. Foodwebs.c. Cross-talk.d. Quorumsensing.


5—Dental Plaque 61

14. Whichofthefollowingaretheweak,long-rangeforcesthatpromoteattachmentofabac-teriumtoasurface?a. Electromagneticenergy.b. Hydrophobicity.c. VanderWaalsforces.d. Cryptitopes.

15. Early colonisers, suchasNeisseria spp., are able todowhichof the following inorder toprovidemorefavourableconditionsforthegrowthofobligatelyanaerobicbacteria?a. Synthesiseproline-richproteins.b. Produceexopolymers.c. Removesialicacidfromhostproteins.d. Consumeoxygenandproducecarbondioxide.

16. The lectin-mediated interaction between streptococci and Actinomyces can be blocked bywhichofthefollowing?a. Galactose.b. Peptides.c. Glucans.d. Proline-richproteins.

17. Whichofthefollowingrepresentsthemeandoublingtimeintheearlystagesoforalplaquegrowth?a. 20minutes.b. 5–6hours.c. 1–2hours.d. 12–15hours.

18. Whichofthefollowingisnotaconsequenceofbiofilmformation?a. Up-regulationofgenesinvolvedwithbacterialcellmotility.b. Enhancedcell-cellsignalling.c. Enhancedhorizontalgenetransfer.d. Reducedsensitivitytoantimicrobialagents.

19. Susceptibleorganismscanappearantibiotic-resistantifneighbouringcellssecretewhichofthefollowing?a. Glucosyltransferases.b. Glucans.c. Proline-richproteins.d. Drug-degradingenzymes.

20. Increased tolerance of biofilm cells to antimicrobial agents is not related to which of thefollowing?a. Increasedageofthebiofilm.b. Beingpartofaplaquecommunity.c. Rapidmicrobialgrowthrates.d. Limitedpenetrationoftheagent.



21. Whichofthefollowingisamajorfactorintheaccumulationofbiofilmsonteeth?a. Abalancebetweenadhesion,growthandremoval.b. Sugarintake.c. Desquamation.d. Theuseoffluoride.

22. Whichofthefollowingisresponsibleforthevariedstructureseenmicroscopicallyincross-sectionsofplaquebiofilms?a. Impactedfoodparticles.b. Alimitednumberofbacterialtypes.c. Ahigherdegreeofmorphologicaldiversity.d. Bacterialsuccession.

23. Decreasedsensitivityofearlybacterialcolonisersofthetoothsurfacetoantimicrobialagentsisduetowhichofthefollowing?a. Dehydration.b. Presenceoftheacquiredpellicle.c. Bacteriagrowinginabiofilm.d. Alimiteddiversityoforganisms.

24. Whichofthefollowingresultsfromthepreparationofmaterialforelectronmicroscopy?a. Openarchitecture.b. Dehydrationofthesample.c. Channelsfilledwithextracellularpolymers.d. Coaggregation.

25. Whichofthefollowingfactorsdirectlyinfluencesthegrowthoftheresidentmicroflora?a. Bacterialsuccession.b. Impactedfoodparticles.c. Dentures.d. Endogenousnutrients.

26. Thepredominantcultivablemicrofloraofthehealthygingivalcreviceincludeslargepercent-agesofwhichofthefollowing?a. Mutansteptococci.b. Neisseria.c. Grampositivefacultativelyanaerobicrods.d. Lactobacilli.

27. Themicrobialcompositionofdentalplaquefromanimals isstudiedforwhichofthefol-lowingreasons?a. Toevaluatethecompositionofplaquefluid.b. Tounderstandthesignificanceofendogenousnutrients.c. Todeterminethesimilaritybetweenmicrofloraofanimalsandhumans.d. Tounderstandbacterialsuccession.

28. Plaquefluidcanbeseparatedfrommicrobialcomponentsbywhichofthefollowingmethods?a. Centrifugation.b. Plaquesampling.c. Isolationtechniques.d. Coadhesion.



29. ThedevelopmentofafoodchainbetweenStreptococcus mutansandVeillonellaspp.,whentheformerismetabolisingfermentablesugars,resultsinwhichofthefollowing?a. Morelacticacid.b. Morecaries.c. Propionicandaceticacids,andmorecaries.d. Propionicandaceticacids,andfewercaries.

30. Whichofthefollowingisthetermusedtodescribecalcifieddentalplaque?a. Apatite.b. Pyrophosphates.c. Calculus.d. Mineralgrowth.

31. Whichofthefollowingdescribescalculusthatisfoundbelowthegingivalmargin?a. Whitlockite.b. Subgingival.c. Apatite.d. Supragingival.

32. Whichofthefollowingingredientinoralcareproductsreducescalculusformation?a. Pyrophosphate.b. Sodiumlaurylsulphate.c. Fluoride.d. Calcium.

33. Whatisthepercentageofadultswhohavecalculus?a. 50%.b. >80%.c. 10%.d. 35%.

34. Whichofthefollowingisnotanexampleofasynergisticmicrobialinteraction?a. Enzymecomplementation.b. Coadhesion.c. Bacteriocinproduction.d. Foodwebformation.

35. Individualspeciesoforalbacteriapossessdifferentbutoverlappingpatternsofwhichofthefollowingtogainnutrientsfromhostmucins?a. Bacteriocins.b. Glycosidases.c. Glucosyltransferases.d. Phosphotransferases.

36. Whichofthefollowingisoneoftheprimaryecologicaldeterminantsindictatingthepreva-lenceofaparticularspeciesinsupragingivaldentalplaque?a. Competitionforendogenousnutrients.b. Salivaryflow.c. Presenceofgingivalcrevicularfluid(GCF).d. Diet.



37. Whichofthefollowingisnotanexampleofanantagonisticinteraction?a. Hydrogenperoxideproduction.b. OrganicacidandlowpHformation.c. Nutrientcompetition.d. Cell-cellsignalling.

38. Whenlactate,producedfromthemetabolismofdietarycarbohydratesfromarangeofbacte-rialspecies,isusedasanutrientbyanotherspecies,thelactate-consumingspeciesisknownaswhichofthefollowing?a. Primaryfeeder.b. Antagonisticspecies.c. Secondaryfeeder.d. Mutuallydependant.

39. Whichofthefollowingisnotamajorcontributingfactorintheorganisedmannerinwhichdentalplaqueforms?a. Interbacterialcoadhesion.b. Interbacterialmetabolicinteractions.c. Genetransfer.d. Cell-cellcommunication.

40. Whichofthefollowingisabenefitofthemicrobialcommunitylifestyletothecomponentspecies?a. Reductionofprotectionfromhostdefences.b. Limitedhabitatrange.c. Increasedsensitivitytoantimicrobialagents.d. Increasedmetabolicefficiency.

41. Whichofthefollowingisnota‘non-immunological’factorresponsibleforthebreakdownofmicrobialhomoeostasisindentalplaque?a. Xerostomia.b. Broadspectrumantibiotictreatment.c. Infection-inducedmyelosuppression.d. Increasedgingivalcrevicularfluidflow.

42. Whichofthefollowingisnotapropertyofthematrixofmicrobialbiofilms?a. Restrictsthepenetrationofchargedantimicrobialagents.b. Contributestothestructuralintegrityofthebiofilm.c. Retainsnutrientsandenzymeswithinthebiofilm.d. Increasesdesiccation.

43. Whichof the following is not an immunological factor responsible for thebreakdownofmicrobialhomoeostasisindentalplaque?a. Xerostomia.b. Neutrophildysfunction.c. sIgAdeficiency.d. Chemotherapy-inducedmyelosuppression.



Feedback1. ANS:c

a. Plaquethatbecomescalcifiedisreferredtoascalculusortartar.b. Salivaisthefluidinthemouththatcarriesmultiplecomponentsthatplayasignificant

roleinthehomoeostasisoftheoralcavity.c. Correct. Dental plaque is a general term for the complex microbial community that

developsonthetoothsurface.d. Dental stain is the chromogenic formation of colour within the pellicle derived from

variousdietarycomponents.

REF:Chapterintroduction,p.74

2. ANS:ba. Pellicleisasurfacefilmthatsalivaryproteinsandglycoproteinsformassoonasatooth

surfaceiscleaned.b. Correct.Thetermbiofilmisusedtodescribecommunitiesofmicroorganismsattached

toasurface.c. Salivarymucinsarehigh-molecular-weightglycoproteins.d. Aplanktoniccommunitywouldbeonein liquidculture,notgrowingasabiofilmlike

dentalplaque.

REF:Microbialbiofilms,pp.75–76

3. ANS:ca. Biofilmsprovideasurfacetowhichchromogenicelementsfromvariousdietarycompo-

nentscanadsorb.b. Oral bacteria growing as a biofilm such as dental plaque display a markedly reduced

sensitivitytoantibiotics.c. Correct.Biofilmscanbeupto1000timesmoretolerantofantimicrobialagents than

thesamecellsgrowinginliquidculture.d. Biofilmprovidesanadherentsurfacetowhichmicrobialpopulationsthatproducecom-

poundsassociatedwithhalitosiscanadhere.

REF:Microbialbiofilms,p.75

4. ANS:ca. Protectionfromhostdefencesincludingtheproductionofextracellularpolymerstoform

afunctionalmatrixprovidingphysicalprotectionfromphagocytosisisageneralpropertyofbiofilms.

b. Abroaderhabitatrangeisageneralpropertyofbiofilms.c. Correct.Biofilmshavebeenshowntohavean‘openarchitecture’withthepresenceof

channelsandvoids.d. Ageneralpropertyofbiofilmsisanenhancedvirulenceandapathogenicsynergismin

abscessesandperiodontaldiseases.

REF:Microbialbiofilms,p.76



5. ANS:da. Bacterial components such as glucosyltransferases and glucan can be detected in

pellicle.b. Proline-richpeptidescanbefoundintheacquiredenamelpellicle.c. Bacterial components such as glucosyltransferases and glucan can be detected in

pellicle.d. Correct.Enolase is an intracellular enzyme found inoral bacteria, but isnot amajor

componentoftheacquiredpellicle.

REF:Acquiredpellicleformation,p.78

6. ANS:ca. Salivaryproteinsandglycoproteinsareadsorbedtoacleantoothsurfaceformingacquired

enamelpelliclebeforetheattachmentofpioneerbacterialspecies.b. An equilibrium between adsorption and desorption of salivary molecules occurs after

90–120minutes.c. Correct.As soon as (within seconds) a tooth surface is cleaned, salivaryproteins and

glycoproteins are adsorbed forming a surface conditioning film which is termed theacquiredenamelpellicle.

d. After2hours,thepellicleonlingualsurfacesis20–80nmthickwhereasbuccalpelliclescanbe200–700nmdeep.

REF:Acquiredpellicleformation,p.78

7. ANS:ba. Dietarycomponentshavelittleinfluenceonthecompositionoforalmicroflora,although

thefrequentintakeoffermentablecarbohydratescanleadtoincreasesinacidogenicandaciduricorganisms.

b. Correct.Microorganismsaregenerallytransportedpassivelytothetoothsurfacebytheflowofsaliva.

c. Colonisationofbacteriaonthetoothsurfaceisnotassociatedwithtoothbrushing.d. Feworalbacterialspeciesaremotile(e.g.,possessflagella),andthesearemainlylocated

subgingivally.

REF:Transportofmicroorganismsandreversibleattachment,p.79

8. ANS:da. Thephysicochemicalinteractionsmaybecomeirreversibleduetoadhesinsonthemicro-

bialcellsurfacebecominginvolvedwithreceptorsintheacquiredpellicle.b. Thephysicochemicalinteractionsmaybecomeirreversibleduetoadhesinsonthemicro-

bialcellsurfacebecominginvolvedwithreceptorsintheacquiredpellicle.c. Thephysicochemicalinteractionsmaybecomeirreversibleduetoadhesinsonthemicro-

bialcellsurfacebecominginvolvedwithreceptorsintheacquiredpellicle.d. Correct.Withinashorttime,thephysicochemicalinteractionsmaybecomeirreversible

due toadhesinson themicrobial cell surfacebecoming involvedwith receptors in theacquiredpellicle.

REF: Pioneer microbial colonisers and irreversible attachment (adhesin–receptor interac-tions),p.80



9. ANS:aa. Correct.Coccalbacteriaattachtotheenamelpellicleaspioneerspeciesonacleanenamel

surfaceinthedevelopmentofdentalplaque;manyofthesebacteriaarestreptococci.b. Withtime,thediversityofthemicrofloraincreases,androdandfilament-shapedbacteria

colonise.c. Withtime,thediversityofthemicrofloraincreases,androdandfilament-shapedbacteria

colonise.d. Spiral-shapedbacteria(i.e.,spirochaetes)arelatecolonisersofthetoothsurface,andare

usuallyfoundsubgingivally.


10. ANS:ca. Glucansarethereceptorforadhesinsformutansstreptococci.b. Fimbriaearesurfacestructuresonbacteria.c. Correct.Hiddenreceptorsforbacterialadhesinshavebeentermedcryptitopes.d. FibrinogenisthereceptorforadhesinsforPorphyromonas gingivalis.


11. ANS:aa. Correct.Microbialsuccessionisthetermusedtodescribethechangeinplaquemicro-

florathatoccursovertimeduetoaseriesofcomplexinteractions.b. Aggregationinvolvescell-to-cellbindinginsaliva,leadingtotheremovalofthebacteria

byswallowing.c. Adhesinsfacilitatetheirreversibleattachmentofcellstothetooththatinvolvesspecific

interactionsbetweencomponentsonthemicrobialcellsurface.d. Desquamationisthesheddingofepithelialcells,whichhelpsreducethemicrobialload

onmucosalsurfaces.

REF:Coaggregation/coadhesionandmicrobialsuccession,pp.82–83

12. ANS:aa. Correct. Pioneer species interact directly with the acquired pellicle while subsequent

biofilmformationisdependantonintra-andintergenericcoadhesionbetweenbacteria.b. Electrostaticattractiveforcesarepartoftheearlyandreversibleattachmentofpioneer

organismstotheconditionedtoothsurface.c. Ifconditionsbecomeunfavourable,somecellsareabletoactivelydetach,providingthe

opportunitytocoloniseothersites.d. Ithasbeenshownthatconsiderablegradientsinkeyfactors(pH,redoxpotential,etc.)

canoccuroverrelativelyshortdistanceswithinbiofilms.

REF:Detachmentfromsurfaces,p.85



13. ANS:da. Genetransferinvolvestheone-waytransferofgeneticmaterialbetweenbacteria.b. Foodwebsareexamplesofnutritionalinterdependanciesbetweenbacteria.c. Certainmembersoftheresidentmicrofloracanalsoengagein‘cross-talk’withthehost,

forexample,bydown-regulatingthepotentialinductionofproinflammatorycytokines.d. Correct.Quorumsensingisthetermusedtodescribetheabilityofindividualcellsto

communicate with, and respond to, neighbouring cells by means of small, diffusible,effectormolecules.

REF:Cell-cellsignalling,p.86

14. ANS:ca. VanderWaalsforcescanpromotereversibleattachment.b. VanderWaalsforcescanpromotereversibleattachment.c. Correct.VanderWaalsforcescanpromotereversibleattachment.d. Crytitopesareinvolvedinstrongirreversibleattachment.

REF:Transportofmicroorganismsandreversibleattachment,p.79

15. ANS:da. Proline-richproteinsarenotsynthesisedbyNeisseriaspp.b. Exopolymersdonotpromotethegrowthofobligatelyanaerobicbacteria.c. Theremovalofsialicacidfromhostproteinswouldnotpromotethegrowthofobligately

anaerobicbacteria.d. Correct.EarlycoloniserssuchasNeisseriaspp.canconsumeoxygenandproducecarbon

dioxide gradually allowing conditions to become more favourable for the growth ofobligatelyanaerobicbacteria.

REF:Coaggregation/coadhesionandmicrobialsuccession,p.83

16. ANS:aa. Correct. Coaggregation often involves lectins, and the lectin-mediated interaction

betweenstreptococciandActinomycescanbeblockedbyaddinggalactoseorlactose.b. Themetabolismofpioneerspeciesgeneratesnutrientssuchaspeptidesthatcanbeused

byotherorganismsasprimarynutrientsources.c. Glucansareextracellularpolymerssynthesisedbysomeadherentbacteriawhichmakea

majorcontributiontotheplaquematrix.d. Proline-richproteinsarereceptorsforActinomyces naeslundii.

REF:Coaggregation/coadhesionandmicrobialsuccession,p.83

17. ANS:ca. Doublingtimesoforalbacteriain vivoareslowerthanevery20minutes.b. Earlybacterialcolonisersdividemorerapidlythanevery5–6hours.c. Correct.Thegrowthrateofindividualbacteriaduringtheearlystagesofplaqueforma-

tionhasameandoublingtimeof1–2hours.d. Thegrowthrateofindividualbacteriawithinplaqueslowsasthebiofilmmatures,andthe

meandoublingtimebecomesbetween12–15hoursafter1–3daysofbiofilmdevelopment.

REF:Maturebiofilmformation,p.83



18. ANS:aa. Correct.Genesassociatedwithcellmotilityaredown-regulatedinbiofilms,asthecells

nowbecomesessile.b. Cellshaveenhancedopportunityforcell-cellsignallinginbiofilms.c. Horizontalgenetransferisenhancedinabiofilm.d. Microorganismshaveareducedsensitivitytoantimicrobialagentsinabiofilm.

REF:Consequencesofbiofilmformation,pp.85–87

19. ANS:da. Bacterialcomponentssuchasglucosyltransferases,detectedinpellicle,playasignificant

roleinattachment.b. Glucansareanextracellularpolymerssynthesisedbysomeadherentbacteriawhichmake

amajorcontributiontotheplaquematrix.c. Proline-richproteinsarereceptorsforA. naeslundii.d. Correct.Beingpartofamicrobialcommunitycaninfluencethesensitivityofcellstoan

antibiotic;susceptibleorganismscanappearresistantifneighbouringcellssecreteadrug-degradingenzyme,suchasbeta-lactamase.

REF:Antimicrobialtolerance,p.87

20. ANS:ca. Olderbiofilmsappearlesssusceptibletoantimicrobialagentsthanyoungerbiofilms.b. Beingpartofamicrobialcommunitycanincreasethetoleranceofamicrobetoananti-

microbialagentduetotheproductionofaneutralisingenzymebyneighbouringcells.c. Correct.The mechanisms that cause the increased tolerance of biofilm cells to anti-

microbialagentsincludeslowmicrobialgrowthrates.d. Increased tolerance of biofilm cells to antimicrobial agents are attributed to limited

penetration,inactivationbyneutralisingenzymes,quenching,unfavourableenvironmen-talconditionsforactivity,slowmicrobialgrowthrates,andexpressionofanovelmicrobialphenotype.


21. ANS:aa. Correct.Theaccumulationofplaqueonteethistheresultofthebalancebetweenadhe-

sion,growthandremovalofmicroorganisms.b. Theingestionofrefinedcarbohydratedoesimpactonplaquegrowth,butisnotamajor

factor. Accumulation is most influenced by a balance between adhesion, growth andremoval.

c. Desquamationisamajorfactorinthecontrolofbiofilmformationonmucosalsurfaces(notteeth).

d. Theuseoffluoridecontributesinaminorcapacitytooneofthethreefactorsaffectingaccumulation:adhesion,growthandremoval.

REF:Structureofmaturedentalplaque,p.87



22. ANS:da. Impactedfoodparticlesarenotinvolvedinthevariousstagesofplaqueformation.b. Alimitednumberofbacterialtypesareinvolvedinonestageofplaquedevelopment.c. Plaque development includes the development of a higher degree of morphological

diversityatonestage.d. Correct. Bacterial succession is responsible for the ‘layering’ effect that takes place in

plaque maturation with an initial limited number of bacterial types followed by theformationofabulklayershowinghighermorphologicaldiversity.


23. ANS:ca. Dehydrationisnotafeaturethatrelatestothedecreasedsensitivitytoantimicrobialagents.b. Thepresenceoftheacquiredpellicledoesnotaffectthesensitivityofbacteriatoanti-

microbialagents.c. Correct.Cellsinbiofilmsdisplayadecreasedsensitivitytoantimicrobialagents.d. Thelimiteddiversityoforganismsdisplayedinearlyplaquedevelopmentisnotindicative

ofadecreasedsensitivitytoantimicrobialagents.


24. ANS:ba. Openarchitectureofasampleistheresultofitbeingviewedbyconfocalmicroscopybut

isnotaresultofthepreparationoftheslideforelectronmicroscopy.b. Correct.Thepreparationofmaterialforelectronmicroscopydehydratesthesampleand

distortsthenaturalstructureofbiofilms.c. Channelsfilledwithextracellularpolymersarenotrelatedtothepreparationofmaterial

forelectronmicroscopy.d. Co-aggregationisaninteractionamongbacteriatoaidincolonisationandisnotinvolved

inmaterialpreparationforelectronmicroscopy.


25. ANS:da. Bacterialsuccessiondoesnotdirectlyinfluencethegrowthofresidentmicroflora.b. Impactedfoodparticlesdonotdirectlyinfluencethegrowthofresidentmicroflora.c. Denturesdonotinfluencethegrowthofresidentmicroflora.d. Correct.Factorsthatinfluencethegrowthoftheresidentmicrofloraincludetheprovi-

sionbythehostofendogenousnutrients.

REF:Bacterialcompositionoftheclimaxcommunityofdentalplaquefromdifferentsites,p.90

26. ANS:ca. Mutan streptococci are not predominant cultivable microflora of the healthy gingival

crevice.b. Neisseriaisnotpredominantcultivablemicrofloraofthehealthygingivalcrevice.c. Correct.Grampositivefacultativelyanaerobicrodsareamongthepredominantcultiva-

blemicrofloraofthehealthygingivalcrevice.d. Lactobacilliarenotthepredominantcultivablemicrofloraofahealthygingivalcrevice.

REF:Gingivalcreviceplaque,p.94



27. ANS:ca. Evaluatingthecompositionofplaquefluidinanimalsisnotareasonthatthereisinterest

inthemicrobialcompositionofdentalplaquefromanimals.b. Understandingendogenousnutrientsisnotareasonthatthereisinterestinthemicrobial

compositionofdentalplaquefromanimals.c. Correct.There is interest in themicrobialcompositionofdentalplaquefromanimals

fortwomainreasons:(a)tostudytheinfluenceofwidelydifferentdietsandlifestylesonthemicrofloraand(b)todeterminethesimilaritybetweenthemicrofloraofananimalandthatofhumanstoascertaintheirrelevanceasamodelofhumanoraldisease.

d. Understandingbacterialsuccessionisnotareasonthatthereis interestindeterminingthesimilaritybetweenmicrofloraofanimalstohumans.

REF:Dentalplaquefromanimals,p.94

28. ANS:aa. Correct.Plaquefluidisthefreeaqueousphaseofplaqueandcanbeseparatedfromthe

microbialcomponentsbycentrifugation.b. Plaquesamplingisamethodofcollection,notthemannerinwhichplaquefluidcanbe

separatedfromthemicrobialcomponents.c. Isolation techniques are not used in the separation of plaque fluid from microbial

components.d. Coadhesionisafactorinvolvedinbeneficialmicrobialinteractionindentalplaque.

REF:Plaquefluid,p.95

29. ANS:da. TheVeillonellaspp.consumelacticacid,notgeneratemorelactate.b. TheVeillonellaspp.,byconsuminglacticacidandproducingweakeracids,reducecaries

inananimalmodel.c. Propionicandaceticacidsaretheproductsofthefoodchain,buttheseareweakeracids,

andsotherearefewercariesinananimalmodel.d. Correct.Propionicandaceticacidsaretheproductsofthefoodchain,andresultinfewer

cariesinananimalmodelbecausetheyareweakeracidsthanlactate.

REF:Microbialinteractionsindentalplaque,Figure5.14,pp.96–97

30. ANS:ca. Apatiteisacomponentofcalculus.b. Pyrophosphateinhibitstheformationofcalculusandisusedindentalproducts.c. Correct.Calculus,ortartar,isthetermusedtodescribecalcifieddentalplaque.d. Mineralgrowthistheprocessofbacteriabeingcoalescedtoformcalculus.

REF:Calculus,p.96

31. ANS:ba. Whitlockiteisacomponentofcalculus.b. Correct.Calculusfoundbelowthegingivalmarginiscalledsubgingivalcalculus.c. Apatiteisacomponentofcalculus.d. Supragingivalcalculusisfoundabovethegingivalmargin.

REF:Calculus,p.96



32. ANS:aa. Correct.Pyrophosphateiscommonlyfoundindentalproductsformulatedtorestrictthe

formationofcalculus.b. Sodiumlaurylsulphatedoesnotinhibitcalculusformationindentalproducts.c. Fluoridedoesnotinhibitcalculusformation.d. Calciumisnotfoundindentalproductstorestricttheformationofcalculus.

REF:Calculus,p.96

33. ANS:ba. No–morethan80%ofadultshavecalculus.b. Correct.Morethan80%ofadultshavecalculus.c. No–morethan80%ofadultshavecalculus.d. No–morethan80%ofadultshavecalculus.

REF:Calculus,p.96

34. ANS:ca. Bacteriapooltheirenzymeresourcesinordertocatabolisecomplexhostmoleculessuch

asmucins.b. Coadhesionenableslatercoloniserstobindtoalreadyattachedearlybacterialcolonising

bacteria.c. Correct.Bacteriocinsareinhibitoryproductsproducedbysomeoralbacteria.d. Food webs enable secondary feeders to utilise the products of metabolism of primary

feedersinamicrobialcommunitysuchasdentalplaque.

REF:Synergisticinteractions,Table5.9,p.96

35. ANS:ba. Bacteriocinsareinhibitoryfactorsthatareinvolvedinmicrobialinteractionsbutdonot

havearoleinpatternsofenzymeactivity.b. Correct.Individualspeciesoforalbacteriapossessdifferentbutoverlappingpatternsof

glycosidaseactivity.c. Glucosyltransferasesareinvolvedinthesynthesisofglucans.d. Phosphotransferasesareinvolvedwithsugartransportinbacteria.

REF:Synergisticinteractions,pp.96–97

36. ANS:aa. Correct.Competitionforhost-derivednutrientsisoneoftheprimaryecologicaldeter-

minantsindictatingtheprevalenceofaparticularspeciesindentalplaque.b. Salivaryflowandswallowingplayaroleinplaqueremoval.c. ThepresenceofGCFdoesnotdictate theprevalenceofaparticular species insupra-

gingivaldentalplaque;itsmaininfluenceisonsubgingivalbiofilms.d. Diethasalimitedinfluenceondeterminingthecompositionofdentalplaque.

REF:Synergisticinteractions,pp.96–97



37. ANS:da. Hydrogenperoxideisinhibitorytothegrowthofmanyoralbacteria.b. Acidproduction,andthegenerationofalowpH,isinhibitorytomanyoralbacteria.c. Competitionfornutrientsisamajorfactordeterminingwhichoralbacteriawillbeable

tocoloniseandgrowsuccessfully.d. Correct. Cell-cell signalling (or quorum sensing) is a mechanism by which bacteria

withinamicrobialcommunityareabletocoordinatetheirgeneexpression,etc.

REF:Antagonisticinteractions,Table5.9,pp.96–99

38. ANS:ca. Aprimaryfeederisabacterialspeciesthatproduces,throughitsownmetabolicprocess,

nutrientsforanotherspecies.b. Anantagonisticspeciesisoneproducinganinhibitoryfactor.c. Correct.Asecondaryfeederisabacterialspeciesthatusesthemetabolicby-productsof

onespeciesasitsownnutritionalsource.d. Mutual dependance is a relationship between bacteria in which both bacteria (lactate

producerandlactateconsumer)aredependantononeanother.

REF:Synergisticinteractions,p.97

39. ANS:ca. Plaqueformsinanorganisedmannerbyinterbacterialcoadhesion,metabolicinteractions

andcell–cellcommunication.b. Plaqueformsinanorganisedmannerbyinterbacterialcoadhesion,metabolicinteractions

andcell–cellcommunication.c. Correct.Genetransferisnotoneofthemajorcontributingfactorsintheformationof

dentalplaque.d. Plaqueformsinanorganisedmannerbyinterbacterialcoadhesion,metabolicinteractions

andcell–cellcommunication.

REF:Dentalplaqueasamicrobialcommunity,p.99

40. ANS:da. Areductionintheprotectionfromhostdefencesisnotabenefitofthemicrobialcom-

munitylifestyle;rather,microbialcommunitiesdisplayanincreasedprotection.b. A limited habitat range is not a benefit of the microbial community lifestyle to the

componentspecies;rather,microbialcommunitiesdisplayanextendedhabitatrange.c. Anincreaseinsensitivitytoantimicrobialagentsisnotabenefitofthemicrobialcom-

munity lifestyle to the component species; rather, microbial communities display adecreasedsensitivityby,forexample,cross-protectionofasensitivespeciesbyaresistantspecies.

d. Correct. An increased metabolic efficiency via food webs and the pooling of enzymecapabilitiesisabenefitofthemicrobialcommunitylifestyletothecomponentspecies.

REF:Dentalplaqueasamicrobialcommunitysummary,p.99



41. ANS:ca. Xerostomia is a non-immunological factor that can cause a breakdown in microbial

homoeostasis.b. Broadspectrumantibioticscandisruptmicrobialhomoeostasis.c. Correct. Infections such as acquired immunodeficiency syndrome (AIDS) affect the

integrityofthehostdefenceswhichcausesabreakdowninmicrobialhomoeostasis.d. IncreasedGCFflowisanon-immunologicalfactorthancandisruptmicrobialhomoe-

ostasisinthegingivalcrevice.

REF:Microbialhomoeostasisindentalplaque,p.101,andTable5.10

42. ANS:da. Thematrixcanrestrictthepenetrationofchargedantimicrobialagentsintothebiofilm.b. The matrix does act as a chemical scaffold to maintain the structural integrity of

biofilms.c. Thematrixdoesretainnutrientsandenzymeswithinthebiofilm.d. Correct.Thematrixalsoretainswaterwithinthebiofilmandsopreventsdesiccation.

REF:Maturebiofilmformation,pp.83–85

43. ANS:aa. Correct.Xerostomiaisthereducedflowofsalivaandis,therefore,notanimmunological

factorresponsibleforthebreakdownofmicrobialhomoeostasisindentalplaque.b. Neutrophil dysfunction is an immunological factor responsible for the breakdown of

microbialhomoeostasisindentalplaque.c. sIgA-deficiencyisanimmunologicalfactorresponsibleforthebreakdownofmicrobial

homoeostasisindentalplaque.d. Chemotherapy-inducedmyelosuppressionisanimmunologicalfactorresponsibleforthe

breakdownofmicrobialhomoeostasisindentalplaque.

REF:Microbialhomoeostasisindentalplaque;Table5.10,p.101


75

C H A P T E R 6

Plaque-Mediated Diseases—Dental Caries and Periodontal Diseases

Multiple Choice1. Historically, for any microbe to be considered responsible for a given condition, Koch’s

postulates were applied. Which of the following is not one of the original Koch’spostulates?a. Eliminationofthemicrobeshouldresultinclinicalimprovement.b. Amicrobeshouldbepresentinsufficientnumberstoinitiatedisease.c. Disease is considered to be the outcome of the overall activity of the total plaque

microflora.d. Themicrobeshouldproducerelevantvirulencefactors.

2. Whichofthefollowingisnotoneofthehypothesesrelatingthecompositionofdentalplaquetocariesorperiodontaldiseases?a. Specificplaquehypothesis.b. Non-specificplaquehypothesis.c. Homeostatichypothesis.d. Ecologicalplaquehypothesis.

3. Whichofthefollowingisatenetofthespecificplaquehypothesis?a. Diseaseistheoutcomeoftheoverallactivityofthetotalplaquemicroflora.b. Only a few species out of thediverse collectionof organisms comprising the resident

plaquemicrofloraareactivelyinvolvedindisease.c. Plaque-mediateddiseasesareessentiallymixedculture(polymicrobial)infections.d. Ahighantibodytitretothemicrobeshouldbedetectedduringinfection;thismayprovide

protectiononsubsequentreinfection.

4. Whichbestrepresentsthegeneralconceptoftheecologicalplaquehypothesis?a. Themicrobeshouldgeneratehighlevelsofspecificantibodies.b. Themicrobesshouldproducerelevantvirulencefactors.c. Theorganismsassociatedwithdiseasemayalsobepresentatsoundsites,butat levels

toolowtobeclinicallyrelevant,butareselectedandmayincreasemarkedlyinnumberfollowingachangeinlocalenvironmentalconditions.

d. Plaque-mediateddiseasesareessentiallymixedculture(polymicrobial)infections,butinwhichonlycertainspeciesareabletopredominate.


76 6—Plaque-MeDiateD Diseases—Dental Caries anD PerioDontal Diseases

5. Which type of epidemiological survey will determine most accurately the role of plaquebacteriaindentaldiseaseandestablishacause-and-effectrelationship?a. Longitudinal.b. Observational.c. Cross-sectional.d. Prospective.

6. Whichofthefollowingbestdefinesthedentalcariesprocess?a. Aggressiveenameldestruction.b. Destructionofthecementum.c. Localised destruction of the tissues of the tooth by bacterial fermentation of dietary

carbohydrates.d. Demineralisationoftherootsurface.

7. Cariesof enamel surfacesareparticularly commonup to theageof20years;whereas, inlaterlife,whichofthefollowingbecomesanincreasingproblem?a. Pitandfissurecaries.b. Interproximalcaries.c. Buccal-surfacecaries.d. Root-surfacecaries.

8. Whichofthefollowingbestdescribestheinitialcariouslesion?a. Smalldemineralisedareasbelowthesurfaceoftheenamel.b. Demineralisationofthecementum.c. Smalldemineralisedareasthatpenetratethroughtheenamel.d. Theinitialcariouslesionisseeninterproximally.

9. Whichofthefollowingresultsintheacidformationthatinitiatesenameldemineralisation?a. Consumptionofhighlyacidicfoods.b. Microbialfermentationofdietarycarbohydrates.c. Limiteduseofdentalfloss.d. Drymouthassociatedwithvariousmedicinalproducts.

10. Whichofthefollowingcanoccurintheinitialstagesofdentalcariesproduction,particularlyinthepresenceoffluoride?a. Rapidcavitation.b. Gingivalrecession.c. Remineralization.d. Furtherdemineralisation.

11. Whichofthefollowingstreptococcihavebeenimplicatedindentalcaries?a. Streptococcus sanguinis.b. Streptococcus sobrinus.c. Streptococcus salivarius.d. Streptococcus oralis.

12. Whichofthefollowingrepresentsthetoothsurfacemostpronetocaries?a. Approximal.b. Buccalsurface.c. Fissuresonocclusalsurfaces.d. Lingualsurface.


6—Plaque-MeDiateD Diseases—Dental Caries anD PerioDontal Diseases 77

13. Whichofthefollowingisthetermappliedtocariesthatrecurbeneathandaroundpreviousrestorations?a. Rampantcaries.b. Periodiccaries.c. Bottlecaries.d. Secondarycaries.

14. Whichofthefollowingisthemainsourceformutansstreptococcifoundinpre-dentateinfants?a. Father.b. Mother.c. Exposuretosugar.d. Grandparents.

15. Theprevalenceof root surface caries increaseswith age;what approximatepercentageofindividualsaged60yearsorolderhaverootcariesorfillings?a. 10%.b. 25%.c. 60%.d. >90%.

16. Which of the following groups of microorganisms are most commonly linked to enameldentalcaries?a. MutansstreptococciandCandida.b. Mutansstreptococciandlactobacilli.c. LactobacilliandActinomyces.d. MutansstreptococciandActinomyces.

17. Themicrofloraassociatedwithrootsurfacecariesisdiverse;whichofthefollowinggroupsofbacteriaaremostcommonlyreportedtobepresentinrootsurfacelesions?a. ActinomycesandVeillonella.b. LactobacilliandVeillonella.c. Mutansstreptococci,lactobacilliandActinomyces.d. Lactobacilli,VeillonellaandPrevotella.

18. Which of the following characteristics do not contribute to the cariogenicicty of mutansstreptococci?a. Rapidsugartransport.b. LowtoleranceofexternalacidicpH.c. Extracellularpolysaccharide(EPS)productionfromsucrose.d. Intracellularpolysaccharide(IPS)production.

19. Whichofthefollowingcanoccurwhenthegingivalcrevicebecomesinflamed?a. Microflorabecomespredominatelyaerobic.b. ThepHdrops.c. Thecrevicedeepenstobecomeapocket.d. Thetemperatureinthecrevice/pocketdrops.



20. Whenattemptingtodeterminethemicrofloraofaperiodontalpocket,carehastobetakentopreservetheviabilityofwhichofthefollowingorganisms?a. Obligatelyanaerobicspecies.b. Aerobicspecies.c. Gramnegativespecies.d. Asaccharolyticbacteria.

21. Whichofthefollowingchangesinlocalsubgingivalenvironmentisinvolvedinthediseaseprocess?a. Theenvironmentfavoursthegrowthofaerobicbacteria.b. Adecreaseintemperature.c. AnincreaseinpH.d. Adecreaseinflowofgingivalcrevicularfluid(GCF).

22. Whichofthefollowingisnotoneofthemaintypesofperiodontaldiseases?a. Chronicperiodontitis.b. Gingivaldiseases.c. Acuteperiodontitis.d. Necrotisingformsofperiodontaldisease.

23. Which of the following would not be considered a modifier of chronic and aggressiveperiodontitis?a. Leukaemia.b. Diabetes.c. Pneumonia.d. Smoking.

24. Whichofthefollowingisnotacharacteristicofchronicmarginalgingivitis?a. Non-specifichostresponse.b. Reversible.c. Non-reversible.d. Inflammatoryresponse.

25. Whatpercentageofthedentatepopulationisaffectedbygingivitisatsomestage?a. 40%.b. 50%.c. 75%.d. 100%.

26. Generally,gingivitisisregardedasresultingfromanon-specificproliferationofthenormalgingivalcrevicemicrofloraduetowhichofthefollowing?a. Mal-occlusion.b. Concomitantmedication.c. Co-existingsystemicdisease.d. Poororalhygiene.



27. Whichofthefollowingproduceexaggeratedclinicalresponses(gingivaemoreoedematousandinflamed)todentalplaque?a. Mal-occlusion.b. Sleep-apnoea.c. Hormonaldisturbances.d. Rheumatoidarthritis.

28. Whichofthefollowingisnotassociatedwiththedevelopmentofgingivitis?a. 10–20foldincreaseinplaquemass.b. ShifttowardsplaquedominatedbyanaerobicGramnegativebacteria.c. Anincreaseinthecarbohydratebalanceinthediet.d. Poororalhygiene.

29. Whichofthefollowingeventsprecedeperiodontitis?a. Increasedcreviculartemperature.b. Gingivitis.c. Cariogenicshiftinbacteria.d. Hormonaldisturbances.

30. Whichofthefollowingisthemostcommonformofadvancedperiodontaldiseaseaffectingthegeneralpopulation?a. Chronicperiodontitis.b. Gingivitis.c. Necrotisingperiodontitis.d. Aggressiveperiodontitis.

31. ApproximatelyhowmanypeopleintheUSAsufferfromchronicperiodontitisduringtheirlife?a. 10%.b. 30%.c. 60%.d. 75%.

32. Whichofthefollowingisnotinvolvedinchronicperiodontitis?a. Lossofattachmentfromgingivatorootsurface.b. Potentialinflammationoftheperiodontalligament.c. Increaseinaerobicbacteriainthegingivalpocket.d. Boneloss.

33. Whichofthefollowingcanpredisposeanindividualtochronicperiodontitis?a. Gingivalhyperplasia.b. Overhangingrestorations.c. Mal-occlusion.d. Toothbrushabrasion.

34. Ashiftinwhichofthefollowingbacteriainitiateinflammation?a. Grampositivefacultativelyanaerobicbacteria.b. Gramnegativefacultativelyanaerobicbacteria.c. Gramnegativeobligateanaerobes.d. Spirochaetes.



35. WhichofthefollowingisnotaGramnegativebacterium?a. Fusobacterium nucleatum.b. Parvimonas micra.c. Prevotella intermedia.d. Porphyromonas gingivalis.

36. Whichofthefollowingisfoundindeepperiodontalpockets?a. Eikenella corrodens.b. Porphyromonas gingivalis.c. Streptococcus intermedius.d. Capnocytophaga gingivalis.

37. Implicit intheecologicalplaquehypothesis is thatdentalcariescanbecontrolledorpre-vented by all of the following strategies, except one.Which one of the following is not astrategythatisconsistentwiththeecologicalplaquehypothesis?a. Directlytargetingtheputativepathogens.b. Stimulatingsalivaflow.c. VaccinationagainstStreptococcus mutans.d. Promotingtheuseofsnackscontainingsugarsubstitutes.

38. Oneofthetheoriesproposedtoexplaintheemergenceofpreviouslyundetectedspeciesinaperiodontalpocketiswhichofthefollowing?a. AnincreaseinGrampositiveaerobicorganisms.b. AnincreaseinGCFflow.c. Amutationinendogenousspecies.d. Colonisationbyexogenouspathogensfromanotherperson.

39. Whichofthefollowingperiodontaldiseasesappearsasamanifestationofunderlyingsys-temicproblemssuchasHIVinfection?a. Necrotizingulcerativegingivitis(NUG).b. Chronicperiodontitis.c. Juvenileperiodontitis.d. Cancrumoris.

40. ThecharacteristicuniquetoNUGiswhichofthefollowing?a. Petechiae.b. Bleedingonprobing.c. Agreypseudomembrane.d. Excessivesalivation.

41. Thebacterialpathogenmostcommonlyassociatedwithlocalisedaggressiveperiodontitisisa. Porphyromonas gingivalis.b. Tannerellaforsythia.c. ‘Redcomplex’bacteria.d. Aggregatibacter actinomycetemcomitans.



42. TheorganismsassociatedwithlesionsinNUGincludewhichofthefollowing?a. Fuso-spirochaetal complex.b. Prevotella nigrescensandPorphyromonas gingivalis.c. Mixedcommunityofspirochaetesonly.d. Mixedcommunityofmotilebacteria.

43. Rapidclinical improvementcanbeseeninthetreatmentofNUGwithwhichofthefol-lowingdrugs?a. Chlorhexidine.b. Metronidazole.c. Penicillin.d. Tetracycline.

44. WhichofthefollowinghostfactorsinGCFcouldactaspredictorsofattachmentloss?a. Prostaglandinlevels.b. Gingipainlevels.c. Leukotoxinactivity.d. Antibodiestothe‘redcomplex’.

45. A 13-year-old female from West Africa presents with localised, rapid onset periodontaldiseaseproducingrapidlossofattachment.Themostlikelydiseasecategoryiswhichofthefollowing?a. Chronicperiodontitis.b. Necrotisingperiodontaldiseases.c. Aggressiveperiodontitis.d. Acutestreptococcalperiodontaldiseases.

46. ThetherapyofchoicefortheeliminationofA. actinomycetemcomitanswhentreatingaggres-siveperiodontitisiswhichofthefollowing?a. Chlorhexidineplusrootplaningandscaling.b. Metronidazoleplusrootplaningandscaling.c. Amoxicillinandmetronidazoleplusrootplaningandscaling.d. Tetracyclineplusrootplaningandscaling.

47. Thedamagedneutrophilsinthemajorityofpatientswithaggressiveperiodontitisproduceavarietyofabnormalitiesincludingwhichofthefollowing?a. Increasedchemotaxis.b. Increasedphagocytosis.c. Decreasedsuperoxideradicalproduction.d. Abnormalsignaltransductionpathways.

48. WhichisamajorvirulencefactorproducedbyA. actinomycetemcomitans?a. Leukotoxinproduction.b. Gingipainproduction.c. Lipoteichoicacid.d. Hydrogenperoxideproduction.



49. The exaggeratedgingivitis seenduring the second trimester inpregnancy is linked to anincreaseintheproportionsofwhichofthefollowingorganisms?a. A. actinomycetemcomitans.b. Treponemaspecies.c. Prevotella intermedia.d. Actinomyces odontolyticus.

50. Achildreportswithulceratedswellingsofthegingivaewhichareacutelypainful;lesionsappearonthelipsandhavelastedapproximately10days.ThecytologicalsmearconfirmsthepresenceofHerpessimplextype1(HSV-1).Whatwouldbethedrugofchoicefortreatment?a. Metronidazole.b. Acyclovir.c. Penicillin.d. Tetracycline.

51. Themodeofactionoffluorideincludesinhibitionofwhichofthefollowing?a. Gingipain,lipopolysaccharide(LPS),leukotoxin.b. Glycolysis,IPSsynthesis,sugartransport.c. Glycolysis,LPS,sugartransport.d. Cellwallsynthesis,IPSsynthesis,sugartransport.

52. Inwhichofthefollowingwaysdoesperiodontaldiseaseinfluencediabetes?a. Increasespancreaticinflammation.b. Predisposesthepersontodiabetestype2.c. Decreasesbloodglucosetriggeringdiabeticincidences.d. Decreasesinsulinresistance.

53. Glycaemiccontrolinthediabeticcanbeimprovedwithwhichofthefollowing?a. Antibiotictherapy.b. Chlorhexidineandrootplaning.c. Hydrogenperoxideandrootplaning.d. Antiviraltherapy.

54. Whichofthefollowingisnotanartificialsweetener?a. Aspartame.b. Casein.c. Xylitol.d. Saccharin.

55. Theclassicformofcancrumorisaffectsmostlywhichagegroup?a. Pregnantwomen.b. Youngchildren.c. Childrenatpuberty.d. Elderly.

56. Nomaismostcommoninwhichofthegeographiclocations?a. Scandinavia.b. NorthAmerica.c. Africa.d. Australasia.



57. TheWorld Health Organization (WHO) estimated that how many children less than 6yearsofagecontractnomaeachyear?a. <1000.b. 30000.c. 7>1000000.d. 200000.

58. Which of the following enables periodontal pathogens to attach to and colonise on thesubgingivaltoothsurfaces?a. Capsule.b. Fimbriae.c. Protease.d. Leukotoxin.

59. WhichofthefollowingisavirulencefactorofP. gingivalis?a. Lipoteichoicacid(LTA).b. Ammonia.c. Gingipain.d. Leukotoxin.

60. Themaindefencestrategybythehostagainstperiodontalpathogensisviawhatcelltype?a. Antibodies.b. Leukocytes.c. Monocytes.d. Neutrophils.

61. Hyaluronidase,chondroitinsulphataseandglycylprolylpeptidaseareexamplesofenzymesinvolvedinwhichphaseofperiodontaldestruction?a. Tissuedamage.b. Tissueinvasion.c. Evasionand/orinactivationofhostdefences.d. Multiplicationofputagenicpathogens.

62. Fortheestablishmentofdisease,organismsmustgainaccesstoandadhereatasusceptiblesite,multiply,overcomeorevadethehostdefences,andwhichofthefollowing?a. Preventexogenousinvasion.b. Produceorinducetissuedamage.c. Providenutrientstothebiofilmattheadvancingfrontofthelesion.d. InducesuppresserTcells.

63. Whichofthefollowingisnotbeingconsideredasapotentialpredictoroffutureperiodontaldiseaseactivity?a. Salivarytestsformutansstreptococciandlactobacilli.b. Rapidmoleculartestsforputativepathogens.c. Enzymedetectioninsubgingivalplaque.d. DetectionofinflammatorymediatorsintheGCF.



64. Evidencesuggestsapotentialassociationbetweenperiodontaldiseasesandgeneralhealth.Whichofthefollowingisnotconsideredtobelinkedtoperiodontaldisease?a. Cardiovasculardisease.b. Aspirationpneumonia.c. Pre-termlabour.d. Hepaticdisorder.

65. Themosteffectivetreatmentforchronicperiodontitisiswhichofthefollowing?a. Sealants.b. Antimicrobialoralrinse.c. Debridementoftherootsurfaces.d. Flossing.

66. The optimum concentration of fluoride supplementation in drinking water for maximalprotectionagainstcariesisapproximatelywhichofthefollowing?a. 1partpermillion(1ppm).b. 10ppm.c. 100ppm.d. 1000ppm.

67. Fluorideisalsofoundnaturallyexistinginwhichofthefollowing?a. Beansandothergreenvegetables.b. Wheatandchicken.c. Teaandinthebonesoffish(especiallysoft-bonedsardinesandsalmon).d. Coffeeandgrapes.

68. Fluorapatitereplaceshydroxyapatiteintoothenamelwhichprovideswhichofthefollowingbenefits?a. Fluorapatiteisawhitercrystalandproducesamoreaestheticappearance.b. Createsasmoothertoothsurfacesothatcalculusbuildupwillhappenatamuchslower

rate.c. Fluorapatiteisstainresistant.d. Fluorapatite isthermodynamicallymorestablethanapatiteandresistsaciddissolution

toagreaterextentthanhydroxyapatite.

69. Anexampleofanantimicrobialthatisinthebisbiguanideclassiswhichofthefollowing?a. Chlorhexidine.b. Thymol.c. Triclosan.d. Sodiumlaurylsulphate.

70. Anexampleofanantimicrobialthatisintheessentialoilclassiswhichofthefollowing?a. Chlorhexidine.b. Thymol.c. Triclosan.d. Sodiumlaurylsulphate.



71. Anexampleofanantimicrobialthatisinthephenolsclassiswhichofthefollowing?a. Chlorhexidine.b. Thymol.c. Triclosan.d. Sodiumlaurylsulphate.

72. Themosteffectiveantimicrobialagentfororaluseinamouthwashtodateiswhichofthefollowing?a. Chlorhexidine.b. Thymol.c. Triclosan.d. Phenol.

73. Polyolshavebeenincorporatedintosugar-freechewinggumstowhatadvantage?a. Areductionintherateofdentalcaries.b. Areductioninthefrequencyofacidattackontheenamel.c. Encouragesremineralisation.d. Alloftheabove.

Feedback1. ANS:c

a. ThateliminationofthemicrobeshouldresultinclinicalimprovementisoneofKoch’spostulates.

b. ThatamicrobeshouldbepresentinsufficientnumberstoinitiatediseaseisoneofKoch’spostulates.

c. Correct.ThefollowingstatementisnotoneofKoch’spostulates:Diseaseisconsideredtobetheoutcomeoftheoverallactivityofthetotalplaquemicroflora,butthismightberelevanttothemicrobialaetiologyoforaldiseases.

d. ThatthemicrobeshouldproducerelevantvirulencefactorsisoneofKoch’spostulates.

REF:Relationshipofplaquebacteriatodisease,p.104

2. ANS:ca. Thespecificplaquehypothesishasbeenproposedtorelateplaquecompositiontooral

disease.b. Thenon-specificplaquehypothesishasbeenproposedtorelateplaquecompositionto

oraldisease.c. Correct.Ahomeostatichypothesishasnotbeenproposed.d. Theecologicalplaquehypothesishasbeenproposedtorelateplaquecompositiontooral

disease.

REF:Relationshipofplaquebacteriatodisease:contemporaryperspectives,p.104.



3. ANS:ba. Thespecificplaquehypothesisproposesthatdiseaseisduetotheactionofaverylimited

(specific)numberofbacteria.b. Correct.The specific plaque hypothesis proposed that only a few species out of the

diverse collection of organisms comprising the resident plaque microflora are activelyinvolvedindisease.

c. Thespecificplaquehypothesisproposesthatdiseaseisduetotheactionofaverylimited(specific)numberofbacteria.

d. Ahighantibodytitretothemicrobeisnotpartofthespecificplaquehypothesis.

REF:Relationshipofplaquebacteriatodisease:contemporaryperspectives,p.104

4. ANS:ca. ThatthemicrobeshouldgeneratehighlevelsofspecificantibodiesisoneoftheKoch’s

postulates.b. That the microbes should produce relevant virulence factors is one of the Koch’s

postulates.c. Correct.Theecologicalplaquehypothesisproposesthattheorganismsassociatedwith

diseasemayalsobepresentatsoundsites,butatlevelstoolowtobeclinicallyrelevant,andachangeinlocalenvironmentalconditionsdrivestheirgrowthandselection.

d. The fact that plaque-mediated diseases are essentially mixed culture (polymicrobial)infections,but inwhichonlycertainspeciesareable topredominate, is relevantbut isnotthemajorconceptbehindtheecologicalplaquehypothesis.

REF:Relationshipofplaquebacteriatodisease:contemporaryperspectives,p.104

5. ANS:aa. Correct.Longitudinalepidemiologicalsurveysprovidethemostinsightintotheroleof

plaquebacteriaindentaldiseaseasitcanestablishcause-and-effectrelationships.b. Observationaldesignisnotasurveydesignusedtodeterminetheroleofplaquebacteria

inhumandisease.c. Cross-sectional design can only determine associations of plaque bacteria in human

diseaseandnotcause-and-effectrelationships.d. Prospectiveisnotasurveydesignusedtodeterminetheroleofplaquebacteriainhuman

disease.

REF:Relationshipofplaquebacteriatodisease:implicationsforstudydesign,p.105

6. ANS:ca. Aggressiveenameldestructionisnotthedefinitionofthecariesprocess.b. Destructionofthecementumisnotthedefinitionofthecariesprocess.c. Correct.Thedentalcariesprocessisthelocaliseddestructionofthetissuesofthetooth

bybacterialfermentationofdietarycarbohydrates.d. Demineralisationoftherootsurfaceisnotthedefinitionofthecariesprocess.

REF:Dentalcaries,p.106



7. ANS:da. Pitandfissurecariesarenotamajorproblemrelatedtoageing.b. Interproximalcariesarenotamajorproblemrelatedtoageing.c. Buccal-surfacecariesarenotamajorproblemrelatedtoageing.d. Correct.Root-surfacecariesareanincreasingproblemduetogingivalrecessionwhich

often accompanies increasing age exposing the vulnerable cementum to microbialcolonisation.


8. ANS:aa. Correct.Cavitiesbeginassmalldemineralisedareasbelowthesurfaceoftheenamel.b. Demineralisationofthecementumisnotpartoftheinitialcarieslesion.c. Smalldemineralisedareas thatpenetrate through theenamelarenot thefirst stage in

thedevelopmentoftheinitialcarieslesion.d. Theinitialcariouslesionisnotnecessarilyseeninterproximally.


9. ANS:ba. Consumptionofhighlyacidgoodsisnotthecauseofbacterialacidproductionseenin

enameldemineralisation,butcancausedentalerosion.b. Correct.Demineralisationoftheenameliscausedbyacidsproducedfromthemicrobial

fermentationofdietarycarbohydrates.c. Limited use of dental floss is not the cause of acid production seen in enamel

demineralisation.d. Drymouthisnotthecauseofacidproductionseeninenameldemineralisation,butlow

salivaflowwillpredisposepatientstocaries.


10. ANS:ca. Cavitationisnotapartoftheinitialcariouslesion.b. Gingivalrecessionisnotapartofthecariesprocess.c. Correct.Theinitialstagesofcariesarereversibleandremineralisationcanoccur,particu-

larlyinthepresenceoffluoride.d. Furtherdemineralisationdoesnotnormallyoccurinthepresenceoffluoride.


11. ANS:ba. S. sanguinishasnotbeenstronglyassociatedwithcaries.b. Correct.S. sobrinusisamemberofthemutansstreptococcusgroupandhasbeenimpli-

catedindentalcaries.c. S. salivariusisnotlinkedtocaries.d. S. oralisisnotlinkedtodentalcaries.

REF:Microbiologyofenamelcaries,pp.107–110



12. ANS:ca. Approximalsurfacesarenotthemostcaries-pronesites.b. Buccalsurfacesarenotthemostcaries-pronesites.c. Correct.Fissuresonocclusalsurfacesarethemostcaries-pronesites.d. Lingualsurfacesarenotthemostcaries-pronesites.

REF:Microbiologyofenamelcaries,p.108

13. ANS:da. Secondarycaries,notrampantcaries,isthetermappliedtocariesthatrecurbeneathand

aroundpreviousrestorations.b. Secondarycaries,notperiodiccaries,isthetermappliedtocariesthatrecurbeneathand

aroundpreviousrestorations.c. Secondarycaries,notbottlecaries,isthetermappliedtocariesthatrecurbeneathand

aroundpreviousrestorations.d. Correct.Secondarycariesdescribethedentalcariesthatrecurbeneathandaroundprevi-

ousrestorations.


14. ANS:ba. Thefatherisnotthemainsourceofmutansstreptococci.b. Correct.Themotheristhemainsourceofthesebacteria.c. Exposuretosugarisnotasourceofmutansstreptococci,butitcanpromotecolonisation

bymutansstreptococci.d. Grandparentsarenotthemainsourceofmutansstreptococci.


15. ANS:ca. 60%ofindividualsaged60yearsorolderhaverootcariesorfillings.b. 60%ofindividualsaged60yearsorolderhaverootcariesorfillings.c. Correct.60%ofindividualsaged60yearsorolderhaverootcariesorfillings.d. 60%ofindividualsaged60yearsorolderhaverootcariesorfillings.

REF:Microbiologyofrootsurfacecaries,pp.110–111

16. ANS:ba. Candidaisnotstronglylinkedtoenameldentalcaries.b. Correct.Mutansstreptococciandlactobacilliarebothstronglylinkedtoenameldental

caries.c. Actinomycesisnotstronglylinkedwithenamelcaries.d. Actinomycesisnotstronglylinkedwithenamelcaries.

REF:Microbiologyofenamelcaries,pp.107–111



17. ANS:ca. Mutansstreptococci,lactobacilliandActinomyceshavebeenlinkedmostcommonlywith

rootsurfacelesions.b. Mutansstreptococci,lactobacilliandActinomyceshavebeenlinkedmostcommonlywith

rootsurfacelesions.c. Correct.Mutansstreptococci,lactobacilliandActinomyceshavebeenlinkedmostcom-

monlywithrootsurfacelesions.d. Mutansstreptococci,lactobacilliandActinomyceshavebeenlinkedmostcommonlywith

rootsurfacelesions.

REF:Microbiologyofrootsurfacecaries,pp.110–112

18. ANS:ba. Rapidsugartransportfacilitatesmorerapidproductionofacidfromdietarycarbohydrates.b. Correct.CariogenicbacteriahaveahightoleranceofexternallowpH,enablingthemto

surviveandgrowunderacidicenvironmentalconditions.c. EPScontributestothebiofilmmatrixandmaylocaliseacidicfermentationproducts.d. IPSallowsacidproductiontocontinueevenintheabsenceofdietarycarbohydrates.

REF:Pathogenicdeterminantsofcariogenicbacteria,Table6.4,pp.114–115

19. ANS:ca. Microfloradoesnotbecomepredominatelyaerobic,butismoreanaerobic.b. ThepHbecomesslightlyalkaline.c. Correct.Indisease,thecrevicebecomesapocket.d. Thetemperatureinthecrevice/pocketactuallyincreases.

REF:Ecologyoftheperiodontalpocket:implicationsforplaquesampling,p.118

20. ANS:aa. Correct.Inthesamplingprocess,carehastobetakentopreserveviabilityofobligately

anaerobicspecies.b. Specialcareinsamplingaerobicspeciesisnotnecessary.c. SpecialcareinsamplingGramnegativespeciesisnotnecessary,thoughmanyofthem

areobligatelyanaerobic.d. Specialcareinsamplingasaccharolyticbacteriaisnotnecessary.

REF: Ecology of the periodontal pocket: implications for plaque sampling, Table 5.7,pp.118–119

21. ANS:ca. Theenvironmentfavoursthegrowthofproteolyticandanaerobicspecies.b. A decrease in temperature does not happen subgingivally—rather, the temperature

increasesslightly.c. Correct.ChangesinsubgingivalregionsuchasincreasesinGCF,pHandtemperature

areallfactorsthatpromotethegrowthofbacteriaimplicatedinperiodontaldisease.d. DecreaseinflowofGCFdoesnothappeninperiodontaldisease—rather,thereisanincrease.

REF:Humanstudies,p.119



22. ANS:ca. Chronicperiodontitisisoneofthemaintypesofperiodontaldiseases.b. Gingivaldiseasesareoneofthemaintypesofperiodontaldiseasecategories.c. Correct.Acuteperiodontitisisnotoneofthe4namedtypesofperiodontaldisease.d. Themaintypesofperiodontaldiseaseare(a)gingivaldiseases,(b)chronicperiodontitis,

(c)necrotisingformsofperiodontaldiseases,and(d)aggressiveperiodontitis.

REF:Microbiologyofperiodontaldiseases,p.119

23. ANS:ca. Chronicandaggressiveperiodontitiscanbelocalisedorgeneralised,andtherecanbemodifiers

ofchronicperiodontitissuchasdiabetes,smoking,certainmedications,andHIVinfection.b. Chronic andaggressiveperiodontitis canbe localisedorgeneralised, and there canbe

modifiers of chronic periodontitis such as diabetes, smoking, certain medications, andHIVinfection.

c. Correct.Pneumoniaisnottypicallyakeymodifierofchronicandaggressiveperiodontaldisease.

d. Chronic andaggressiveperiodontitis canbe localisedorgeneralised, and there canbemodifiers of chronic periodontitis such as diabetes, smoking, certain medications, andHIVinfection.

REF:Microbiologyofperiodontaldisease,p.119

24. ANS:ca. Chronicmarginalgingivitisisanon-specifichostresponsetodentalplaqueinvolvingthe

gingivalmargins.b. Chronicmarginalgingivitisisareversibleinflammatoryresponsetodentalplaqueinvolv-

ingthegingivalmargins.c. Correct.Chronicgingivitisisreversible.d. Chronicmarginalgingivitisisaninflammatoryresponsetodentalplaqueinvolvingthe

gingivalmargins.

REF:Gingivitis,p.120

25. ANS:da. Itisestimatedthatthewholedentatepopulationisaffectedbygingivitisatsomestage.b. Itisestimatedthatthewholedentatepopulationisaffectedbygingivitisatsomestage.c. Itisestimatedthatthewholedentatepopulationisaffectedbygingivitisatsomestage.d. Correct. It is estimated that the whole dentate population is affected by gingivitis at

somestage.


26. ANS:da. Mal-occlusionisnotthegeneralreasonforgingivitistodevelop.b. Concomitantmedicationisnotthegeneralreasonforgingivitistodevelop.c. Co-existingsystemicdiseaseisnotthegeneralreasonforgingivitistodevelop.d. Correct.Generally,gingivitisisregardedasresultingfromanon-specificproliferationof

normalgingivalcrevicemicrofloraduetopoororalhygiene.




27. ANS:ca. Mal-occlusiondoesnotgenerallyplayaroleingingivitis.b. Sleep-apnoeadoesnotgenerallyplayaroleingingivitis.c. Correct.Theclinicalsignsareexaggeratedandthegingivaearemoreoedematousand

inflamedinindividualsexperiencinghormonaldisturbances.d. Rheumatoidarthritisdoesnotplayaroleingingivitis.


28. ANS:ca. 10–20foldincreaseinplaquemassisassociatedwiththedevelopmentofgingivitis.b. AshifttowardsplaquedominatedbyanaerobicGramnegativebacteriaisassociatedwith

thedevelopmentofgingivitis.c. Correct.Anincreaseinthecarbohydratebalanceinthedietisnotassociatedwiththe

developmentofgingivitis.d. Poororalhygieneisassociatedwiththedevelopmentofgingivitis.


29. ANS:ba. An increase in crevicular temperature does not have to precede the development of

periodontitis.b. Correct.Whileitisacceptedthatnotallgingivitisprogressestomoreseriousformsof

periodontitisitisagreeduponthatgingivitismustprecedeperiodontitis.c. Cariogenicshiftinbacteriadonothavetoprecedethedevelopmentofperiodontitis.d. Hormonaldisturbancesdonothavetoprecedethedevelopmentofperiodontitis.


30. ANS:aa. Correct.Chronicperiodontitisisthemostcommonformofadvancedperiodontaldisease

affectingthegeneralpopulationandamajorcauseoftoothlossaftertheageof25years.b. Chronic periodontitis, not gingivitis, is the form of periodontal disease affecting the

generalpopulationandamajorcauseoftoothlossafterageof25.c. Chronicperiodontitis,notnecrotisingperiodontitis, is the formofperiodontaldisease

affectingthegeneralpopulationandamajorcauseoftoothlossafterageof25.d. Chronic periodontitis, not aggressive periodontitis, is the form of periodontal disease

affectingthegeneralpopulationandamajorcauseoftoothlossafterageof25.

REF:Chronicperiodontitis,p.120

31. ANS:ba. IntheUSA,aboutonethirdofadultssufferfromthediseaseatsometimeduringtheirlife.b. Correct. In the USA, about one third of adults suffer from the disease at some time

duringtheirlife.c. IntheUSA,aboutonethirdofadultssufferfromthediseaseatsometimeduringtheir

life.d. IntheUSA,aboutonethirdofadultssufferfromthediseaseatsometimeduringtheir

life.




32. ANS:ca. Lossofattachmentfromgingivatorootsurfaceisinvolvedinchronicperiodontitis.b. Potentialinflammationoftheperiodontalligamentisinvolvedinchronicperiodontitis.c. Correct.Itisanincreaseinanaerobicbacteriainthegingivalpocketthatisimplicated

inchronicperiodontitis.d. Bonelossisinvolvedinchronicperiodontitis.


33. ANS:ba. Gingival hyperplasia does not necessarily predispose someone towards chronic

hyperplasia.b. Correct. Overhanging restorations is a factor that can enhance plaque retention and

predisposesomeonetowardschronicperiodontitis.c. Mal-occlusiondoesnotnecessarilypredisposesomeonetowardschronicperiodontitis.d. Toothbrushabrasionisnotafactorinchronicperiodontitis.

REF:Chronicperiodontitis,pp.120–121

34. ANS:ca. Grampositivefacultativelyanaerobicbacteriaareassociatedprimarilywithsubgingival

health.b. Gram negative facultatively anaerobic bacteria are not associated with initiation of

disease.c. Correct.Gramnegativeobligateanaerobesareassociatedwithgingivalinflammation.d. Spirochaetesareassociatedwithamoreseverediseasestateandappearlaterintheinflam-

matoryprocess.


35. ANS:ba. F. nucleatumisGramnegative.b. Correct.P. micraisGrampositive.c. P. intermediaisGramnegative.d. P. gingivalisisGramnegative.


36. ANS:ba. E. corrodensisgenerallyassociatedwithhealthysites.b. Correct.P. gingivalisisfoundindeepperiodontalpockets.c. S. intermediusisgenerallyassociatedwithhealthysites.d. C. gingivalisisgenerallynotassociatedwithdeepperiodontalpockets.




37. ANS:ca. Directly targeting the putative pathogens is still consistent with the ecological plaque

hypothesis.b. Stimulatingsalivaflowisconsistentwiththeecologicalplaquehypothesis.c. Correct.Active vaccination against S. mutans is not consistentwith the ecological plaque

hypothesis.Otherbacteriawithrelevanttraitswouldstillbecapableofcausingcaries.d. The use of snacks with non-fermentable sweeteners is consistent with the ecological

plaquehypothesis.

REF:Re-evaluationofthemicrobialaetiologyofdentalcaries,pp.115–116

38. ANS:ba. Grampositiveanaerobicorganismsdonotplayasignificantroleinchronicperiodontitis.b. Correct.AnincreaseinGCFflowcanprovideanovelsourceofnutrientswhichcould

enrichthegrowthofpreviouslyundetectedspecies.c. Amutation inendogenousspecieswouldnotexplaintheemergenceofpreviouslyun-

detectedspecies.d. There is very little evidence that acquisitionofpathogens fromanotherpersonwould

leadtodetectablelevelsofanexogenouspathogeninaperiodontalpocket.


39. ANS:aa. Correct.NUG(andnecrotizingulcerativeperiodontitis)canbemanifestationsofunder-

lyingsystemicproblemssuchasHIVinfection.b. ChronicperiodontitisisnotassociatedwithunderlyingsystemicproblemssuchasHIV

infection.c. JuvenileperiodontitisisnotassociatedwithunderlyingsystemicproblemssuchasHIV

infection.d. Cancrumoris(noma)isnotassociatedwithunderlyingsystemicproblemssuchasHIV

infectionandislinkedmoretomalnutritionandacompromisedimmunesystem.

REF:Necrotisingperiodontaldiseases,p.123

40. ANS:ca. PetechiaearenotacharacteristicofNUG.b. Bleedingonprobingisauniversalcharacteristicofperiodontaldiseases.c. Correct.NUGischaracterisedclinicallyby the formationofagreypseudomembrane

onthegingivaewhicheasilysloughsoffrevealingableedingareabeneathit.d. Excessivesalivationisnotacharacteristicofperiodontaldiseases.


41. ANS:da. P. gingivalisisnotparticularlyassociatedwithlocalisedaggressiveperiodontitis.b. T. forsythiaisnotassociatedwithlocalisedaggressiveperiodontitis.c. ‘Redcomplex’bacteriaarenotassociatedwithlocalisedaggressiveperiodontitis.d. Correct. A. actinomycetemcomitans is associated with localised forms of aggressive

periodontitis.

REF:Aggressiveperiodontitis,pp.124–126



42. ANS:aa. Correct.Afuso-spirochaetalcomplexofbacteriacanbeseeninsmearsofaffectedlesions.b. P. nigrescensandP. gingivalisarenotbothassociatedwithNUGlesions.c. Spirochaetesarenottheonlybacteriapresentintheselesions.d. Motilebacteriaarenottheonlybacteriapresentintheselesions.


43. ANS:ba. Chlorhexidinehasnotbeenreportedtobeeffectiveineliminatingthefuso-spirochaetal

complexfrominfectedsites.b. Correct.Metronidazole is effective ineliminating the fuso-spirochaetal complex from

infectedsitesandthusisassociatedwithrapidclinicalimprovement.c. PenicillinisnotusedinthetreatmentofNUG.d. TetracyclinetherapyhasnotproveneffectiveinthetreatmentofNUG.


44. ANS:aa. Correct.ProstaglandinsinGCFcorrelatewithperiodontalstatusandcouldactaspredic-

torsofattachmentloss.b. Gingipainsarebacterialvirulencefactors.c. Leukotoxinsarebacterialvirulencefactors.d. Antibodiestothe‘redcomplex’ofbacteriahavenotbeenshowntocorrelatewithattach-

mentloss.

REF:Pathogenicmechanismsinperiodontaldisease,pp.128–130

45. ANS:ca. Chronicperiodontitisdoesnotpresentwithlocalised,rapidonset.b. Necrotisingperiodontaldiseasepresentswithlesionsspreadingintothecheek,faceand

neckcausingextensivetissueloss.c. Correct.Aggressiveperiodontitisisarareconditionthatusuallyoccursinadolescents.

Thediseaseappearstostartaroundpuberty,ismorecommoningirls,withcasesoftenclusteredinfamilies,andwithrapidlossofattachment.Thediseaseshowssomeracialpredispositions,asitisslightlymorecommoninpeopleofWestAfricanandAsianorigin.

d. Acutestreptococcalgingivitisresultsinsevereillness,butnotperiodontalinvolvement.

REF:Aggressiveperiodontitis,p.125

46. ANS:ca. Chlorhexidine plus root planing and scaling is an inadequate therapy for aggressive

periodontitis.b. Metronidazole plus root planing and scaling is an inadequate therapy for aggressive

periodontitis.c. Correct.Thecombinationofmetronidazoleandamoxicillinhasbeenfoundtobepar-

ticularlyeffectivewhencombinedwithscalingandrootplaning.d. Tetracycline does not always lead to complete elimination of A. actinomycetemcomitans

fromthepocket.




47. ANS:da. The damaged neutrophils in the majority of patients with aggressive periodontitis

producedecreasedchemotaxis.b. The damaged neutrophils in the majority of patients with aggressive periodontitis

producedecreasedphagocytosis.c. The damaged neutrophils in the majority of patients with aggressive periodontitis

produceincreasedsuperoxideradicalproduction.d. Correct.Thedamagedneutrophilsinthemajorityofpatientswithaggressiveperiodon-

titis produce a variety of abnormalities including abnormal signal transductionpathways.


48. ANS:aa. Correct.StrainsofA. actinomycetemcomitansproducearangeofvirulencefactors,includ-

ingapowerfulleukotoxin.b. GingipainisavirulencefactorofP. gingivalis.c. LipoteichoicacidispresentinthecellwallofsomeGrampositivebacteria.d. A. actinomycetemcomitansdoesnotproducehydrogenperoxide.


49. ANS:ca. A. actinomycetemcomitansislinkedtoaggressiveperiodontitis.b. Treponemaspeciesareassociatedwithnecrotisingperiodontaldiseases.c. Correct.P. intermediaislinkedtopregnancygingivitis.d. A. odontolyticusisevidentinhealthysites.

REF:Otherperiodontaldiseases,p.127

50. ANS:ba. Acyclovir or penciclovir would be the antiviral drug effective against acute herpetic

gingivostomatitis.b. Correct. Acyclovir or penciclovir would be the antiviral drug effective against acute

herpeticgingivostomatitis.c. Acyclovir or penciclovir would be the antiviral drug effective against acute herpetic

gingivostomatitis.d. Acyclovir or penciclovir would be the antiviral drug effective against acute herpetic

gingivostomatitis.


51. ANS:ba. Thesearevirulencefactorsassociatedwithperiodontaldisease,andarenotaffectedby

fluoride.b. Correct.Glycolysis,IPSsynthesisandsugartransportareinhibitedbyfluoride.c. LPSproductionisnotinhibitedbyfluoride.d. Cellwallsynthesisisnotinhibitedbyfluoride.

REF:Fluoride,p.138



52. ANS:ba. Periodontaldiseasedoesnotcausepancreaticinflammationtooccur.b. Correct. Periodontal pathogens may raise pro-inflammatory mediators that result in

insulinresistanceandan increase inbloodglucose, therebypredisposing individuals todeveloptype2diabetes.

c. Periodontaldiseaseincreasesbloodglucose.d. Periodontaldiseaseincreasesinsulinresistance.


53. ANS:ba. There is no evidence to suggest that antibiotic therapy alone will improve glycaemic

controlinadiabetic.b. Correct. Mechanical treatment of periodontitis, when combined with antimicrobial

agents,canimproveglycaemiccontrol.c. Evidence does not suggest that hydrogen peroxide combined with root planing will

improveglycaemiccontrolinadiabetic.d. Thereisnoevidencetosuggestthatantiviraltherapywillimproveglycaemiccontrolin

adiabetic.


54. ANS:ba. Aspartameisanintenseartificialsweetener.b. Correct.Caseinisaproteinfoundinmilkandisnotanartificialsweetener.c. Xylitolisanintensenaturalsweetener.d. Saccharinisanintenseartificialsweetener.

REF:Sugarsubstitutes,pp.141–142

55. ANS:ba. Cancrumorisaffectsyoungchildren.b. Correct.Cancrumorisaffectsyoungchildren,althoughimmunocompromisedadultscan

alsobeaffected.c. Cancrumorisaffectsyoungchildren.d. Cancrumorisaffectsyoungchildren.


56. ANS:ca. NomaismostcommoninAfrica.b. NomaismostcommoninAfrica.c. Correct.NomaismostcommoninAfrica.d. NomaismostcommoninAfrica.




57. ANS:da. Approximately200000childrenunder6yearsofagecontractnomaeachyear.b. Approximately200000childrenunder6yearsofagecontractnomaeachyear.c. Approximately200000childrenunder6yearsofagecontractnomaeachyear.d. Correct.Approximately200000childrenunder6yearsofagecontractnomaeachyear;

consequently,nomahasbeendeclaredaprioritybyWHO.


58. ANS:ba. Capsuleisaboneresorbingfactorinvolvedintissuedamage.b. Correct.Periodontalpathogensattachtoandcoloniseonthesubgingivaltoothsurface

throughattachmentmechanismssuchasadhesinsandfimbriae.c. Theproductionofproteaseobtainsnutrientsformultiplicationandgrowth.d. Leukotoxinisamechanismintheevasionofhostdefences.

REF:Pathogenicmechanismsinperiodontaldisease,p.130

59. ANS:ca. LTAispresentonGrampositivebacteria.b. AmmoniacanbecytotoxicbutisnotproducedbyP. gingivalis.c. Correct.ThegingipainsofP. gingivaliscancontributetodegradationofkeyhostmol-

ecules,therebyderegulatingthehostresponseandpromotingvascularpermeability.d. LeukotoxinisproducedbyA. actinomycetemcomitans.


60. ANS:da. Antibodiesarepresent,butdonotformthemaindefencestrategybythehostagainst

periodontalpathogens.b. Phagocyticcellssuchasneutrophilsformthemaindefencestrategybythehostagainst

periodontalpathogens.c. Phagocyticcellssuchasneutrophilsformthemaindefencestrategybythehostagainst

periodontalpathogens.d. Correct.Phagocyticcellssuchasneutrophilsformthemaindefencestrategybythehost

againstperiodontalpathogens.




61. ANS:aa. Correct.Tissue-damagingenzymesproducedbysubgingivalbacteriathatmaydamage

tissue matrix molecules directly include hyaluronidase, chondroitin sulphatase andglycylprolyl.

b. Microbial invasion of host tissues occurs in NUG, where there is superficial invasionof the gingival connective tissues by spirochaetes; enzymes do not play a role inthatprocess.

c. Evasion and/or inactivation of host defences is a function of leukotoxin and the hostreleaseofpro-inflammatorycytokines.

d. Multiplicationofputagenicpathogensisaidedbyproteaseproduction,thedevelopmentoffoodchains,andaninhibitorproduction,suchasbacteriocins.


62. ANS:ba. Preventinganexogenousinvasionofmicrobesisafunctionofthehostdefences.b. Correct.Fortheestablishmentofdisease,organismsmustgainaccesstoandadhereat

asusceptiblesite,multiply,overcomeorevadethehostdefencesandproduceorinducetissuedamage.

c. Providing nutrients to the advancing front of the lesion is not part of diseaseestablishment.

d. InducingsuppresserTcellsisafunctionofhostdefenceevasion.

REF:Pathogenicsynergismandperiodontaldisease,p.132

63. ANS:aa. Correct.Salivarytestsformutansstreptococciandlactobacillarebeingconsideredasa

potentialindicatorforcariesandnotperiodontaldisease.b. Sensitiveandrapidmoleculartestsforputativepathogensareconsideredsensitivepredic-

torsoffuturediseaseactivity.c. Enzyme detection in subgingival plaque is considered a sensitive predictor of future

diseaseactivity.d. DetectionofinflammatorymediatorsintheGCFisconsideredasensitivepredictorof

futurediseaseactivity.

REF:Predictorsofdiseaseactivity,p.135

64. ANS:da. Evidencesuggeststhatanassociationexistsbetweenperiodontaldiseaseandcardiovas-

culardisease.b. Oralmicroorganisms,includingperiodontalpathogens,cancauseaspirationpneumonia

insusceptiblepatients.c. Pre-termlabourhasbeenassociatedwithperiodontaldisease.d. Correct.Hepaticdisordershavenotbeenassociatedwithperiodontalbacteria.

REF:Predictorsofdiseaseactivity,pp.136–137



65. ANS:ca. Sealantsareadentalcariestreatment.b. Antimicrobialoralrinseisaplaquecontrolmeasure.c. Correct.Debridementof the root surfaces is themost effective treatment for chronic

periodontitis.d. Flossingisasupragingivalplaquecontrolmeasure.

REF:Approachesforcontrollingplaque-mediateddiseases,p.137

66. ANS:aa. Correct.Theoptimumconcentrationformaximalprotectionagainstcariesisapproxi-

mately1partpermillion(1ppm).b. Theoptimumconcentrationformaximalprotectionagainstcariesisapproximately1part

permillion(1ppm).c. Theoptimumconcentrationformaximalprotectionagainstcariesisapproximately1part

permillion(1ppm).d. Theoptimumconcentrationformaximalprotectionagainstcariesisapproximately1part

permillion(1ppm).

REF:Fluoride,p.138

67. ANS:ca. Fluorideisfoundnaturallyinteaandinthebonesoffish(especiallysoft-bonedsardines

andsalmon).b. Fluorideisfoundnaturallyinteaandinthebonesoffish(especiallysoft-bonedsardines

andsalmon).c. Correct.Fluorideisfoundnaturallyinteaandinthebonesoffish(especiallysoft-boned

sardinesandsalmon).d. Fluorideisfoundnaturallyinteaandinthebonesoffish(especiallysoft-bonedsardines

andsalmon).

REF:Fluoride,p.138

68. ANS:da. Fluorapatiteisinvisibleanddoesnotcreateawhitetoothsurface.b. Fluorapatitedoesnotproduceasmoothertoothsurface.c. Fluorapatiteisnotstainresistant.d. Correct. Fluorapatite is thermodynamically more stable than apatite and resists acid

dissolutiontoagreaterextentthanhydroxyapatite.

REF:Fluoride,p.138

69. ANS:aa. Correct.Chlorhexidineisanantimicrobialthatisinthebisbiguanideclass.b. Thymolisintheclassofessentialoils.c. Triclosanisintheclassofphenols.d. Sodiumlaurylsulphateisintheclassofsurfactants.

REF:Antimicrobialagents,pp.140–141



70. ANS:ba. Chlorhexidineisabisbiguanide.b. Correct.Thymolisanexampleofanantimicrobialthatisintheessentialoilclass.c. Triclosanisaphenol.d. Sodiumlaurylsulphateisintheclassofsurfactants.


71. ANS:ca. Chlorhexidineisabisbiguanide.b. Thymolisanexampleofanantimicrobialthatisintheessentialoilclass.c. Correct.Triclosanisanexampleofanantimicrobialthatisinthephenolclass.d. Sodiumlaurylsulphateisintheclassofsurfactants.


72. ANS:aa. Correct.Chlorhexidineisthemosteffectiveantimicrobialagentfororalusetodateand

canbesuccessfullyformulatedintoamouthrinse.Thisbisbiguanidehasabroadspectrumofactivityagainstyeasts,fungi,andawiderangeofGrampositiveandGramnegativebacteria.

b. Essentialoils(menthol,thymol,eucalyptol,etc.)havebeensuccessfullyformulatedintoa mouthwash and shown to penetrate plaque biofilms, but are not as effective aschlorhexidine.

c. Triclosan is themost commonlyused antimicrobial agent in toothpastesbut isnot aseffectiveaschlorhexidine.

d. Triclosanisaphenol,themostcommonlyusedantimicrobialagentintoothpastes,butisnotaseffectiveaschlorhexidine.

REF:Antimicrobialagents,pp.140,141

73. ANS:da. Polyolshavebeenincorporatedintosugar-freechewinggums;theuseoftheseproducts

threeormoretimesadaycanreducetheincidenceofcaries,byreducingthefrequencyof acid attack on the enamel and by stimulating saliva flow, thereby encouragingremineralisation.

b. Polyolshavebeenincorporatedintosugar-freechewinggums;theuseoftheseproductsthreeormore timesadaycanreduce the incidenceofcaries,byreducingthe frequencyofacidattackontheenamelandbystimulatingsalivaflow,therebyencouragingremineralisation.

c. Polyolshavebeenincorporatedintosugar-freechewinggums;theuseoftheseproductsthreeormoretimesadaycanreducetheincidenceofcaries,byreducingthefrequencyof acid attack on the enamel and by stimulating saliva flow, thereby encouragingremineralisation.

d. Correct.Polyolshavebeenincorporatedintosugar-freechewinggums;theuseoftheseproductsthreeormoretimesadaycanreducetheincidenceofcaries,byreducingthefrequencyofacidattackontheenamelandbystimulatingsalivaflow,therebyencouragingremineralisation.

REF:Sugarsubstitutes,p.141


101

C H A P T E R 7

Orofacial Bacterial Infections

Multiple Choice1. Dentalplaqueisacausalfactorinwhichofthefollowing?

a. Periodontitis.b. Angularcheilitis.c. Ludwig’sangina.d. Drysocket.

2. Studies have revealed that the types of bacteria isolated from orofacial infections reflectwhichofthefollowing?a. Polymicrobialinfections,withawidespectrumoffacultativebacteriaandstrictlyanaero-

bicbacteria.b. Obligatelyanaerobicbacteriaonly.c. Grampositiveanaerobicbacteriaonly.d. Gramnegativeanaerobicbacteriaonly.

3. Whatistheprimarysourceofnutrientsformicroorganismsisolatedfromorofacialinfections?a. Serum-derivedproteins.b. Gingivalcrevicularfluid(GCF)-derivedproteins.c. Saliva-derivedproteins.d. Proteinsderivedfromthediet.

4. What is the most appropriate sampling technique for specimens with which to diagnoseorofacialinfections?a. Moistswabsplacedimmediatelyintophosphate-bufferedsaline(PBS).b. Moistswabdirectlyintoreducedtransportfluid.c. Aspirationofpusbysyringe.d. Wholesaliva.

5. Whatisaclinicalfeatureofdrysocket?a. Xerostomia.b. Bacterialsialadenitis.c. Halitosis.d. Pseudomembraneformationoversocket.

6. Whichisthebacteriummostcommonlyisolatedfromcasesofcervicofacialactinomycosis?a. Actinomyces naeslundii.b. Actinomyces actinomycetemcomitans.c. Actinomyces bovis.d. Actinomyces israelii.


102 7—OrOfacIal BacterIal InfectIOns

7. Whichofthefollowingisalocalisedcollectionofbacteria,inflammatorycells,tissuebreak-downproducts,serum-derivedproteinsandotherorganicmaterial?a. Periodontitis.b. Abscess.c. Gingivitis.d. Cellulitis.

8. Inflammationintosurroundingsofttissuesfromadentoalveolarabscessisdefinedbywhichofthefollowingterms?a. Periodontitis.b. Abscess.c. Lateralperiodontalabscess.d. Cellulitis.

9. Whatistheantibioticofchoicefortreatingcervicofacialactinomycosis?a. Erythromycin.b. Metronidazole.c. Amoxicillin.d. Clindamycin.

10. Whichof the followingmake it difficult todetermine the causativemicroorganisms in aspecificorofacialinfection?a. Localanatomicalstructures.b. Samplecontamination.c. Septicaemia.d. Pyrexia.

11. It is importantthatpussamplesfromorofacial infectionsbeobtainedviaaspirationtech-niquesforwhichofthefollowingreasons?a. Toincludesalivaforafullmicrobialsampling.b. GCFcandiluteandmasksomemicroorganisms.c. Toprotectoxygensensitiveanaerobesfromoxygen.d. Tospeedupthecultureprocess.

12. Whichofthefollowingisthereasonthatidentificationofbacteriawithinorofacialinfectionscantakeanumberofdays?a. Timetakeninplatingthebacteriaontoselectiveandnon-selectiveagarplates.b. Slow-growingnatureofobligateanaerobes.c. Lackofknowledgeofoptimalcultureconditions.d. Samplecontaminationwithsaliva.

13. Thereducedin vitroantimicrobialsusceptibilitytopenicillinsandotherantibioticsofbac-teriarecoveredfromorofacialinfectionsisduetowhichofthefollowing?a. Contaminationofcultures.b. Emergenceofantibioticresistance.c. Availabilityofnutrientsandcomplementaryenzymes.d. Reducedactivityofpenicillinsandotherantibiotics.


7—OrOfacIal BacterIal InfectIOns 103

14. Whichofthefollowingisamajorreasonfortheemergenceofpenicillinresistanceinoralbacterialspeciesencounteredinthemouth?a. Hypersensitivitytopenicillin.b. Catalaseproductionbydiversemicrobialcommunities.c. Theemergenceofbeta-lactamase-producingbacteria.d. Synergismtotheincidenceofclindamycinresistance.

15. Whichofthefollowingisagoodalternativeantibioticagentforpatientshypersensitivetopenicillins?a. Cephalosporin.b. Amoxicillin.c. Erythromycin.d. Ornidazole.

16. Whichofthefollowingrepresentsanendotoxinfoundwithininfectedrootcanalsinsymp-tomaticteeth?a. Lipoteichoicacid.b. Macrophages.c. Lipopolysaccharides.d. Granulomatousmaterial.

17. Whichof the following terms isused todescribe thepyogenic condition that affects theteethandsupportingstructures?a. Dentoalveolarinfection.b. Stomatitis.c. Chronicasymptomaticlesion.d. Necrosis.

18. Alateralperiodontalabscesscanbedifferentiatedfromadentoalveolarabscessbywhichofthefollowing?a. Necroticpulpisevidentattheapexoftheroot.b. Thetoothhasavitalpulp.c. Thetoothrequiresurgentantibiotictherapy.d. Thetoothdoesnothaveavitalpulp.

19. Whichofthefollowingisoftenthecauseofaperiodontalabscess?a. Traumatothetooth.b. Coronalcaries.c. Foreignmaterialinaperiodontalpocket.d. Rootcaries.

20. Recent research indicates that the complex polymicrobial community within endodonticinfectionsissimilartowhichofthefollowing?a. Acutedentoalveolarabscess.b. Angularcheilitis.c. Rootcaries.d. Drysocket.



21. Whichofthefollowingisthemostcommoncauseofpulpdeaththataccompaniesanacutedentoalveolarabscess?a. Lossofsupportingbone.b. Advanceddentalcaries.c. Trauma.d. Periapicalgranuloma.

22. Thepulpofatoothmaybecomenecroticduetolossofitsbloodsupplyasaresultofwhichofthefollowing?a. Periodofchronicinfection.b. Lossofsupportingbone.c. Trauma.d. Periodontitis.

23. Whatisthedrugofchoicetotreatstaphylococcallymphadenitis?a. Metronidazole.b. Flucloxacillin.c. Amoxycillin.d. Tetracycline.

24. Theonsetofacuteinflammationinvolvedwithacutedentoalveolarabscessesproduceswhichfollowingcharacteristicsignorsymptom?a. Toothmobility.b. Severepain.c. Periapicalgranuloma.d. Gingivalinflammation.

25. Themajorityofcasesofdentoalveolarabscessescanbemanagedsuccessfullybywhichofthefollowing?a. Intravenousantibiotics.b. Prescribingoralantibiotictherapy.c. Establishingasurgicaldrain.d. Usingantimicrobialrinses.

26. Animalstudieshaveimplicatedwhichofthefollowingasthecausalorganismofdisseminat-inginfectionfromaninfectedrootcanaltodistantorgans?a. Porphyromonas gingivalis.b. Olsenella profusa.c. Treponema denticola.d. Enterococcus faecalis.

27. Osteomyelitis in the jaw is rare, but is sometimes a consequence of which of thefollowing?a. Radiotherapy.b. Trauma.c. Peri-implantitis.d. Xerostomia.



28. Whichofthefollowingisthemostfrequentlyoccurringorofacialbacterialinfection?a. Peri-implantitis.b. Pericronitis.c. Acutedentoalveolarabscess.d. Drysocket.

29. Theonsetof raisedbody temperatureandmalaiseassociatedwithanacutedentoalveolarabscessarearesponsetowhichofthefollowing?a. MethicillinresistantStaphylococcus aureus(MRSA).b. Grampositiveanaerobes.c. Circulatinginflammatorycytokines.d. Macrophages.

30. Which of the following is an emerging form of periodontitis associated with toothreplacement?a. Bacterialsialadenitis.b. Denturestomatitis.c. Peri-implantitis.d. Sjögren’ssyndrome.

31. Inflammationofthesofttissuescoveringorimmediatelyadjacenttothecrownofapartiallyeruptedtoothisreferredtoaswhichofthefollowing?a. Peri-implantitis.b. Alveolarosteitis.c. Osteomyelitis.d. Pericoronitis.

32. Faciallacerationsinvolvingtheface,neckandscalparemostcommonlyinfectedwithwhichofthefollowing?a. ‘Redcomplex’anaerobes.b. Oralstreptococci.c. Staphylococcus epidermidisandPropionibacterium acnes.d. OralGrampositiveanaerobes.

33. Irrigationwithwhichofthefollowinghasbeenfoundtobebeneficialinthetreatmentofperi-implantitis?a. Anon-antimicrobialrinse/irrigationsolutionsuchassaliva.b. Chlorhexidine.c. Fluoriderinse.d. Apredominatelyalcohol-basedsolution.

34. Aggregatesfoundinpusfromsinusesgeneratedincervicofacialactinomycosisarereferredtoaswhichofthefollowing?a. Sulphurgranules.b. Granulomas.c. Macrophage–microbeaggregates.d. Fibrinolysis.



35. Pericoronitisoccursduetowhichofthefollowing?a. Herpeticlesions.b. Trauma.c. Eruptinglowerthirdmolarteethinyoungadults.d. Inflammationfoundinperiodontalpockets.

36. Pericoronitisismostoftencausedbywhichofthefollowing?a. Over-instrumentationduringanoralprophylaxis.b. Infectioninthespacebetweenthetoothandoverlyingsofttissue.c. Overgrowthbyanaerobicbacteria.d. MRSA.

37. Arecentsimpletesttodeterminetheminimuminhibitoryconcentration(MIC)forapar-ticularantibioticonanagarplateiswhichofthefollowing?a. A-test.b. E-test.c. R-test.d. MIC-test.

38. Whichofthefollowingisthetermforinflammationofthesalivaryglands?a. Stomatitis.b. Xerostomia.c. Pericoronitis.d. Sialadenitis.

39. Sialadenitiswithintheparotidglandisusuallyduetothepresenceofwhichofthefollowing?a. Cheekbitetrauma.b. Underlyingxerostomia.c. Gingivalinflammation.d. Softtissueabscess.

40. Sialadenitiswithintheparotidglandisusuallyduetothepresenceofunderlyingxerostomiaoftenassociatedwithwhichofthefollowing?a. Pericoronitis.b. Sjögren’ssyndrome.c. Gingivalinflammation.d. Alveolarosteitis.

41. Sialadenitisinthesubmandibularglandismostfrequentlysecondarytowhichofthefollowing?a. Alveolarosteitis.b. Pericoronitis.c. Salivarystoneblockage.d. Stomatitis.

42. Pusfromsuppurativeparotitisfromshouldbecollectedbyaspirationoftheductorificeinordertominimisewhichofthefollowing?a. Antimicrobialresistance.b. Recurrentparotitis.c. Riskofsamplecontaminationfromthemicroflorainsaliva.d. Angularcheilitis.



43. Whichofthefollowingdescribestheconditionthatrepresentsanareaofinflammationthatislocalisedtotheanglesofthemouth?a. Angularcheilitis.b. Stomatitis.c. Herpeticlesion.d. Alveolarosteitis.

44. TheinflammatorychangesobservedinangularcheilitisareassociatedwiththepresenceofStaphylococcus aureusorwhichofthefollowing?a. Aggregatibacter actinomycetemcomitans.b. Porphyromonas gingivalis.c. Candidaspp.d. Treponemaspp.

45. Which isanexampleofanopportunistic infectioncausedbymembersof theActinomycesgenus?a. Denturestomatitis.b. Angularcheilitis.c. Cervicofacialactinomycosis.d. Ludwig’sangina.

46. Whichofthefollowingisaspecificconditioninwhichapatient,usuallyachild,developsalocalisedpainfulswellingofthefaciallymphnode?a. Pericoronitis.b. Lymphadenitis.c. Cervicofacialactinomycosis.d. Angularcheilitis.

Feedback1. ANS:a

a. Correct.Dentalplaqueisacausalfactorinperiodontitis.b. Dentalplaqueisnotacausalfactorofangularcheilitis.c. DentalplaqueisnotacausalfactorofLudwig’sangina.d. Dentalplaqueisnotacausalfactorofdrysocket.

REF:Introduction,p.149

2. ANS:aa. Correct.Contemporarymicrobiologicalstudieshaverevealedthatthetypesofbacteria

recovered from orofacial dental infections reflect the wide spectrum of facultative andstrictlyanaerobicbacteriaandcanberegardedasapolymicrobialinfection.

b. Themicroflorafoundinorofacialdental infections ismorediversethan justanaerobicbacteria.

c. Gram positive bacilli are not only the predominant species involved in orofacialinfection.

d. Gram negative bacteria are not the only type of organism found in orofacialinfections.




3. ANS:aa. Correct.Themicroflorauseserum-derivedproteinsastheirmainsourceofnutrients.b. GCF-derivedproteinsarethemajorsourceofproteinsforbacteriaintheinflamedperi-

odontalpocket,butnotfororofacialinfections.c. Saliva-derivedproteinsmayinfluencesupragingivalplaque,butnotorofaciallesions.d. Proteinsfromthediethavelittleimpactontheoralmicroflora.

REF:Orofacialbacterialinfections,p.147

4. ANS:ca. Swabsarenotanefficientmethodofsampling,andsensitiveanaerobicbacteriawould

loseviabilityinPBS.b. Swabs are not the most efficient method of sampling, though reduced transport fluid

wouldhelppreservetheviabilityofobligatelyanaerobicbacteria.c. Correct.Aspirationofpusbysyringewillminimisetheriskofcontaminationandpre-

servetheviabilityofobligatelyanaerobicspecies.d. Salivawillnotberepresentativeofthebacteriapresentinanorofaciallesion.

REF:Laboratorydiagnosis,Figure7.3,p.148

5. ANS:ca. Xerostomiaisnotafeaturelinkedtodrysocket.b. Bacterialsialadenitisisnotafeaturelinkedtodrysocket.c. Correct.Drysocketoftenhaspronouncedhalitosis.d. Theformationofapseudomembraneisnotlinkedtodrysocket.

REF:Drysocket,pp.154–155

6. ANS:da. A. naeslundiiisisolatedonlyoccasionallyfromlesions.b. A. actinomycetemcomitansbelongstothegenusAggregatibacterandisnotassociatedwith

actinomycosis.c. A. bovisisisolatedonlyoccasionallyfromlesions.d. Correct.A. israeliiisassociatedwith90%ofcasesofactinomycosis.

REF:Cervicofacialactinomycosis,p.157

7. ANS:ba. Periodontitisisnotalocalisedcollectionofbacteria,inflammatorycells,tissuebreakdown

products,serum-derivedproteins,andotherorganicmaterial.b. Correct.Anabscessisalocalisedcollectionofbacteria,inflammatorycells,tissuebreak-

downproducts,serum-derivedproteinsandotherorganicmaterial.c. Gingivitisisnotalocalisedcollectionofbacteria,inflammatorycells,tissuebreakdown

products,serum-derivedproteinsandotherorganicmaterial.d. Cellulitis is the subsequent inflammation in the soft tissue which can lead to limited

localisedmusclemovement.




8. ANS:da. Periodontitisisnottheresultoftheperforationofthesurroundingbone.b. Anabscessisnottheinflammationinsurroundingsofttissuesfollowingtheperforation

ofthedentoalveolarprocess.c. A lateralperiodontalabscessdoesnotperforatethebonespreading infection intosur-

roundingsofttissues.d. Correct. Cellulitis occurs when a dentoalveolar abscess perforates the bone, which

permitsspreadofinfectionandsubsequentinflammationintosurroundingsofttissues.


9. ANS:ca. Erythromycincanbeusedforpatientswhoarehypersensitivetopenicillins.b. Metronidazoleisnotanantibioticofchoiceforthiscondition.c. Correct.Amoxicillinistheantibioticofchoice.d. Clindamycincanbeusedforpatientswhoarehypersensitivetopenicillins.

REF:Cervicofacialactinomycosis,pp.157–158

10. ANS:ba. Local anatomical structures are not a problem associated with recovery of causative

microorganismsfoundfromspecificorofacialinfections.b. Correct.Themicroorganismspresentinsalivacanoftenposeamajorproblemwiththe

recoveryofthecausativemicroorganismsfoundinspecificorofacialinfections.c. Septicaemiaisalife-threateningconditionwherebacteriaenterthebloodstream.d. Pyrexiaisanelevatedtemperatureanddoesnotinterferewithmicroorganismisolation

andidentification.

REF:Laboratorydiagnosis,p.148

11. ANS:ca. Contaminationistobeavoided,hencetheaspirationtechniqueprotocol.b. GCFdoesnotplayaroleinobtainingsamplesofapurulentorofacialinfection.c. Correct.Samplesofpusshouldbeobtainedbyaspirationtominimisetheriskofcon-

taminationandprotectoxygensensitiveanaerobesfromatmosphericoxygen.d. Identificationofbacteriawithinorofacial infectionscan takeanumberofdaysdue to

theslow-growingnatureofmanystrictanaerobes.Thisfactorlimitstheclinicalbenefitofsamplingsuchinfectionsviaaspirationoranyothermeans.




12. ANS:ba. The time taken inplating thebacteria isnot the reason that identificationofbacteria

withinorofacialinfectionstakesanumberofdays.Theslow-growingnatureofanaerobescanmaketheidentificationofbacteriawithinorofacialinfectionstakeanumberofdays.

b. Correct.Theslow-growingnatureofanaerobescanmaketheidentificationofbacteriawithinorofacialinfectionstakeanumberofdays.

c. Lackofknowledgeofoptimalculturemethodsisnotthemainreasonthatidentificationofbacteriawithinorofacialinfectionstakesanumberofdays.Theslow-growingnatureof anaerobes can make the identification of bacteria within orofacial infections take anumberofdays.

d. Samplecontaminationisnotthemainreasonthatidentificationofbacteriawithinoro-facialinfectionstakesanumberofdays.Theslow-growingnatureofanaerobescanmaketheidentificationofbacteriawithinorofacialinfectionstakeanumberofdays.Samplecontaminationcanhamperaccuratediagnosis.


13. ANS:ba. Theemergenceofantibioticresistance,notculturecontamination,playsaroleincausing

bacteria recovered fromorofacial infections tohavereduced in vitroantimicrobial sus-ceptibilitytopenicillinsandotherantibiotics.

b. Correct.Theemergenceofantibioticresistanceiscausingbacteriarecoveredfromoro-facial infections tohave reduced in vitro antimicrobial susceptibility topenicillins andotherantibiotics.

c. Theavailabilityofnutrientsandcomplementaryenzymesdonotplayaroleincausingbacteria recovered fromorofacial infections tohavereduced in vitroantimicrobial sus-ceptibilitytopenicillinsandotherantibiotics.

d. Reducedactivityofpenicillinsandotherantibioticsdoesnotplayaroleincausingbac-teria recovered from orofacial infections to have reduced in vitro antimicrobialsusceptibility.

REF:Antimicrobialsusceptibility,p.149

14. ANS:ca. Patients sensitive to penicillin are not a major reason for the emergence of penicillin

resistance.b. Catalasecanbreakdownhydrogenperoxide,notpenicillin.c. Correct.Thewidespreaduseofpenicillinhascontributedtotheemergenceofpenicillin

resistanceinoralbacterialspeciesbecauseithasbeenshownthattheadministrationofpenicillinleadstotheemergenceofbeta-lactamase-producingbacteria,especiallyGramnegativebacilli,insitessuchastheoropharynx.

d. The incidenceof resistance toclindamycin is extremely low,even incountries suchasGermany and Japan, where this agent is frequently used to treat acute dentalinfections.

REF:Principlesofmanagement,p.150



15. ANS:ca. Erythromycin is the alternative drug of choice for patients with hypersensitivity to

penicillins.b. Erythromycin is the alternative drug of choice for patients with hypersensitivity to

penicillins.c. Correct.Erythromycinisagoodalternativeagentforpatientswithhypersensitivityto

penicillins.d. Erythromycin is a good alternative agent for patients with hypersensitivity to

penicillins.

REF:Principlesofmanagement,p.150

16. ANS:ca. LipoteichoicacidisfoundinGrampositivebacteria,andisnotanendotoxin.b. Macrophagesarephagocyticcellsandnotendotoxins.c. Correct.Inadditiontotheidentificationofbacteria,studieshavequantifiedthepresence

ofendotoxinswithinrootcanals;higherlevelsoflipopolysaccharidewerefoundinteethwithclinicalsymptomscomparedwithasymptomaticteeth.

d. Granulomatousmaterialisfoundattheapexofchronicrootinfections.

REF:Endodonticinfection,p.151

17. ANS:aa. Correct.Thetermdentoalveolarinfectioncanbeusedtodescribepyogenicconditions

thataffecttheteethandsupportingstructures.b. Stomatitisisageneraltermusedtodescribeaninflamedandsoremouthwhichmayor

maynotbeassociatedwithpus.c. Chronicasymptomaticlesionsindicateanasymptomatic,long-term(chronic)infection.d. Necrosisisatermusedtodescribedeathofbodytissue.

REF:Dentoalveolarinfection,p.151

18. ANS:ba. Necroticpulpisnotevidentattheapexoftherootinatoothwithalateralperiodontal

abscess.b. Correct. The lateral periodontal abscess can be differentiated from a dentoalveolar

abscessbythefactthatithasavitalpulp.c. Antibiotictherapyisrarelyrequired.d. Atoothwithalateralperiodontalabscesshasavitalpulp.

REF:Lateralperiodontalabscess,p.151

19. ANS:ca. Aperiodontalabscessisnotcausedbytraumatothetooth.b. Coronalcariesdonotcauseaperiodontalabscess.c. Correct.Theperiodontalabscessdevelopsasaresultofthepresenceofforeignmaterial

inanestablishedperiodontalpocket.d. Rootcariesdonotcauseaperiodontalabscess.

REF:Lateralperiodontalabscess,p.151



20. ANS:aa. Correct. Recent research indicates that the complex polymicrobial community within

endodonticinfectionsissimilartothatfoundindentoalveolarabscesses.b. Themicroflorafoundinendodonticinfectionsisnotsimilartoangularcheilitis.c. Themicrofloraofrootcariesisnotsimilartoendodonticinfections.d. Theaetiologyofdrysocketisnotfullyunderstood.


21. ANS:ba. Loss of supporting bone is not the cause of pulp death in an acute dentoalveolar

abscess.b. Correct.Advanceddentalcariesarethemostcommoncauseofpulpdeathinanacute

dentoalveolarabscess.c. Onoccasion,thepulpofatoothmaydieduetolossofbloodsupplyfromtrauma,but

itisnotthemostcommoncauseofpulpdeathinanacutedentoalveolarabscess.d. Periapical granuloma is not the cause of pulp death in an acute dentoalveolar

abscess.

REF:Acutedentoalveolarabscess,p.151

22. ANS:ca. A period of chronic infection is not a cause of pulp death that accompanies an acute

dentoalveolarabscess.b. Lossofsupportingboneisnotacauseofpulpdeaththataccompaniesanacutedento-

alveolarabscess.c. Correct.Occasionally,thepulpofatoothmaybecomenecroticduetolossofitsblood

supplyasaresultoftrauma,suchasablowtothetooth.d. Periodontitisisnotacauseofpulpdeaththataccompaniesanacutedentoalveolarabscess.


23. ANS:ba. Flucloxacillinisthedrugofchoiceforstaphylococcallymphadenitis.b. Correct.Flucloxacillinisthedrugofchoiceforstaphylococcallymphadenitis.c. Flucloxacillinisthedrugofchoiceforstaphylococcallymphadenitis.d. Flucloxacillinisthedrugofchoiceforstaphylococcallymphadenitis.

REF:Staphylococcallymphadenitis,p.158

24. ANS:ba. Toothmobility is not an immediate signof theonset of acute inflammation involved

withacutedentoalveolarabscesses.b. Correct.Theonsetofacute inflammation involvedwithacutedentoalveolarabscesses

producesthecharacteristicsymptomofseverepain.c. Periapicalgranuloma,oftenasymptomatic,isnotanimmediatesignorsymptomofthe

onsetofacuteinflammationinvolvedwithacutedentoalveolarabscesses.d. Gingival inflammation is not an immediate sign of the onset of acute inflammation

involvedwithacutedentoalveolarabscesses.




25. ANS:ca. Intravenousantibioticswouldnotnormallybeusedtomanagethemajorityofcasesof

dentoalveolarabscesses.b. Oralantibioticsmaybeusedadjunctivelyinthemanagementofdentoalveolarabscesses.c. Correct.Themajorityofcasesofdentoalveolarabscessescanbemanagedsuccessfully

byestablishingasurgicaldrainalone.d. Antimicrobialrinsesalonewouldnotbesufficienttreatmentfordentoalveolarabscesses.


26. ANS:ca. AnimalstudieshavenotimplicatedP. gingivalisasthecauseofdisseminatinginfection

fromtherootcanaltodistantorgans.b. AnimalstudieshavenotimplicatedO. profusaasbeingthecauseofdisseminatinginfec-

tionfromtherootcanaltodistantorgans.c. Correct.AnimalstudieshaveimplicatedT. denticolaasbeingthecauseofdisseminating

infectionfromtherootcanaltodistantorgans.d. AnimalstudieshavenotimplicatedE. faecalisasbeingthecauseofdisseminatinginfec-

tionfromtherootcanaltodistantorgans.


27. ANS:aa. Correct.Radiotherapy,resultinginreducedvascularity,isassociatedwithosteomyelitis.b. Radiotherapyisassociatedwithosteomyelitis.c. Radiotherapyisassociatedwithosteomyelitis.d. Radiotherapyisassociatedwithosteomyelitis.

REF:Osteomyelitis,p.153

28. ANS:ca. Acutedentoalveolarabscessisthemostfrequentlyoccurringorofacialbacterialinfection.b. Acutedentoalveolarabscessisthemostfrequentlyoccurringorofacialbacterialinfection.c. Correct.Acutedentoalveolarabscessisthemostfrequentlyoccurringorofacialbacterial

infection.d. Acutedentoalveolarabscessisthemostfrequentlyoccurringorofacialbacterialinfection.


29. ANS:ca. MRSAisnotassociatedwiththeonsetofraisedbodytemperatureandmalaiseassociated

withanacutedentoalveolarabscess.b. Grampositiveanaerobesarenotassociatedwith theonsetof raisedbody temperature

andmalaiseassociatedwithanacutedentoalveolarabscess.c. Correct.The onset of raised body temperature and malaise associated with an acute

dentoalveolar abscess are a consequence of circulating inflammatory cytokines, inter-leukins,andtumournecrosisfactorinresponsetobacterialendotoxin.

d. Macrophagesarenotassociatedwiththeonsetofraisedbodytemperatureandmalaiseassociatedwithanacutedentoalveolarabscess.




30. ANS:ca. Bacterialsialadenitisisnotanemergingformofperiodontitisthatisadirectconsequence

oftheincreasinguseofdentalimplants.b. Denturestomatitisisnotanemergingformofperiodontitisthatisadirectconsequence

oftheincreasinguseofdentalimplants.c. Correct. Peri-implantitis is an emerging form of periodontitis that is a direct conse-

quenceoftheincreasinguseofdentalimplants.d. Sjögren’ssyndromeisnotanemergingformofperiodontitisthatisadirectconsequence

oftheincreasinguseofdentalimplants.

REF:Peri-implantitis,p.155

31. ANS:da. Peri-implantitisisnotinflammationofthesofttissuescoveringorimmediatelyadjacent

tothecrownofapartiallyeruptedtooth,butinflammationsurroundinganimplant.b. Alveolarosteitisisnotinflammationofthesofttissuescoveringorimmediatelyadjacent

tothecrownofapartiallyeruptedtooth,butaninflammationofthealveolarbonetypi-callyoccurringasapostoperativecomplicationoftoothextraction.

c. Osteomyelitis isnot inflammationof thesoft tissuescoveringor immediatelyadjacenttothecrownofapartiallyeruptedtooth,butaninfectionandinflammationoftheboneorbonemarrow.

d. Correct.Inflammationofthesofttissuescoveringorimmediatelyadjacenttothecrownofapartiallyeruptedtoothisreferredtoaspericoronitis.

REF:Pericoronitis,p.155

32. ANS:ca. ‘Redcomplex’anaerobesareassociatedwithperiodontitisratherthanfaciallacerations.b. Oralstreptococciarenotassociatedwithfaciallacerations.c. Correct.Facial lacerationsareassociatedwithmembersofthecommensalskinmicro-

flora,suchasStaphylococcus epidermidisandPropionibacterium acnes.d. OralGrampositiveanaerobesarenotassociatedwithfaciallacerations.

REF:Faciallacerations,p.158

33. ANS:ba. Anon-antimicrobialrinse/irrigationsolutionwouldnotbeeffectiveinthetreatmentof

peri-implantitis.Treatmentrequiresantimicrobialactivity.b. Correct.Irrigationwithanantiseptic,suchaschlorhexidine,hasbeenfoundtobeben-

eficialinthetreatmentofperi-implantitis.c. A fluoride rinse is not an effective approach for the treatment of peri-implantitis.

Treatmentrequiresantimicrobialactivity.d. Apredominatelyalcohol-basedsolutionisnotanacceptedtreatmentofperi-implantitis.

Treatmentrequiresantimicrobialactivity.

REF:Peri-implantitis,p.155



34. ANS:aa. Correct.Theaggregatesarereferredtoas‘sulphurgranules’.b. Theaggregatesarereferredtoas‘sulphurgranules’.c. Theaggregatesarereferredtoas‘sulphurgranules’.d. Theaggregatesarereferredtoas‘sulphurgranules’.

REF:Cervicofacialactinomycosis,pp.157–158

35. ANS:ca. Herpeticlesionsarenotthecauseofpericoronitis.b. Pericoronitisdoesnotoccurasaresultoftrauma;however,iftheoperculumisswollen,

itmaypreventteethfromfullyoccludingandleadtopainandtissuetrauma.c. Correct.Pericoronitisoccursfrequentlyinrelationtoeruptinglowerthirdmolarteeth

inyoungadults.d. Pericoronitisisnottheinflammationfoundinperiodontalpockets.


36. ANS:ba. Anoralprophylaxisisnotacauseofpericoronitis.b. Correct.Pericoronitisoccursfairlyfrequentlyandisduetoinfectioninthespacebetween

thetoothandoverlyingsofttissue.c. Anaerobicbacteriaarenotnecessarilythecauseofpericoronitis.d. MRSAisnotthecauseofpericoronitis.


37. ANS:ba. TheE-testallowsdirectreadingofanantimicrobialMICfromanagarplate.b. Correct.TheE-testallowsdirectreadingofanantimicrobialMICfromanagarplate.c. TheE-testallowsdirectreadingofanantimicrobialMICfromanagarplate.d. TheE-testallowsdirectreadingofanantimicrobialMICfromanagarplate.

REF:Antimicrobialsusceptibility,Figure7.5,pp.149–150

38. ANS:da. Stomatitis refers to any inflammatoryprocess affecting themucousmembranesof the

mouthandlips.b. Xerostomia is a dry mouth as a result of a change in salivary flow or salivary

composition.c. Pericoronitis is inflammation of the soft tissues surrounding the crown of a partially

eruptedtooth.d. Correct.Sialadenitisisthetermforinflammationofthesalivaryglands.

REF:Bacterialsialadenitis,p.155



39. ANS:ba. Sialadenitiswithintheparotidglandisnottheresultoftrauma.b. Correct.Sialadenitiswithintheparotidglandisoftenduetothepresenceofunderlying

xerostomia.c. Sialadenitiswithintheparotidglandmayco-existwithgingival inflammationbut it is

notthecause.d. Sialadenitiswithintheparotidglandisnotduetothepresenceofasoft-tissueabscess.


40. ANS:ba. Pericoronitisisnotassociatedwithxerostomiaandisnotthecauseofsialadenitis.b. Correct.Sialadenitiswithintheparotidglandisusuallyduetothepresenceofunderlying

xerostomiaasaresultofSjögren’ssyndrome.c. Gingival inflammation is not associated with xerostomia and is not the cause of

sialadenitis.d. Alveolarosteitisisnotassociatedwithxerostomiaandisnotthecauseofsialadenitis.


41. ANS:ca. Sialadenitisinthesubmandibularglandissecondarytoblockagebyasalivarystone,not

alveolarosteitis.b. Sialadenitisinthesubmandibularglandissecondarytoblockagebyasalivarystone,not

pericoronitis.c. Correct.Sialadenitisinthesubmandibularglandismostfrequentlysecondarytoblock-

agebyasalivarystone.d. Stomatitis refers to any inflammatoryprocess affecting themucousmembranesof the

mouthandlips.


42. ANS:ca. Pusfromsuppurativesialadenitisshouldbecollectedbyaspirationoftheductorificeto

avoidcontaminationfromoralmicroflora.b. Recurrent parotitis of childhood is relatively rare, but does occur. However, pus from

suppurative sialadenitis should be collected by aspiration of the duct orifice to avoidcontaminationfromoralmicroflora.

c. Correct.Pusfromsuppurativesialadenitisshouldbecollectedbyaspirationoftheductorificeinordertominimisetheriskofsamplecontaminationfromthemicroflorafoundinsaliva.

d. Angularcheilitis,aninflammationlocalisedtotheanglesofthemouth,isnotassociatedwithsuppurativeparotitis.Pusfromsuppurativesialadenitisshouldbecollectedbyaspira-tionoftheductorificetoavoidcontaminationfromoralmicroflora.




43. ANS:aa. Correct.Angularcheilitisdescribestheconditionthatrepresentsanareaofinflammation

thatislocalisedtotheanglesofthemouth.b. Stomatitis refers to any inflammatoryprocess affecting themucousmembranesof the

mouthandlips.c. Aherpeticlesionisaviralinfectionandcouldoccuratasitesimilartothatofangular

cheilitis. However, angular cheilitis describes the condition that represents an area ofinflammationthatislocalisedtotheanglesofthemouth.

d. Alveolarosteitisisinflammationofthealveolarbone,notsofttissue.

REF:Angularcheilitis,p.156

44. ANS:ca. The inflammatory changes are not associated with the presence of A.

actinomycetemcomitans.b. TheinflammatorychangesarenotassociatedwiththepresenceofP. gingivalis.c. Correct.Theinflammatorychangesareassociatedwiththepresenceofstaphylococcior

Candida,eitheraloneorincombination.d. The inflammatorychangesseenwithangularcheilitisareassociatedwiththepresence

ofTreponemaspp.


45. ANS:ca. DenturestomatitisiscausedbyCandidaspp.b. TheinflammatorychangesassociatedwithangularcheilitisarecausedbyStaphylococcus

aureus,MRSA,andCandidaspp.c. Correct.Cervicofacialactinomycosisisanexampleofanopportunisticinfectioncaused

bymembersoftheActinomycesgenus.d. Ludwig’sanginaismainlyassociatedwithobligatelyanaerobicbacteria.


46. ANS:ba. Pericoronitisinvolvessoft-tissueswellingcoveringthecrownofapartiallyeruptedtooth.b. Correct.Lymphadenitisisaspecificconditioninwhichapatient,usuallyachild,devel-

opsalocalisedpainfulswellingofthefaciallymphnode.c. Cervicofacialactinomycosispresentsasasubmandibularswellingandisassociatedwith

A. israelii.d. Angularcheilitisisanareaofinflammationlocalisedtotheanglesofthemouth.

REF:Staphylococcallymphadenitis,p.158


118

C H A P T E R 8

Antimicrobial Prophylaxis

Multiple Choice1. Theempiricaloveruseofantibioticshasbeenaccompaniedbyanenormousincreaseinthe

emergenceofmicrobial resistance;whichof the followingdescribeswhat impact thathashadontheuseofantimicrobials?a. Antisepticsareusedasanalternativetoantibiotics.b. Antibioticsareusedforshortertreatmentcourses.c. Antibioticsareineffectiveformanycommondiseases.d. Antibioticsshouldneverbeusedastheyexacerbatebacterialresistance.

2. Whichisthemostcommonbacteriumisolatedfromcasesofinfectiveendocarditis?a. Streptococci.b. Staphylococci.c. Candidaspp.d. Enterococci.

3. Whichof thefollowingisnotoneof thefouroccasionswhenprophylacticantimicrobialsareindicated?a. Theriskofpost-operativeinfectionishigh.b. Whenwoundsarecontaminatedwithsoilordirt(e.g.,afterroadtrafficaccidents)and

thereisariskofinfection(e.g.,Clostridium tetani).c. Tomeetpatientdemand.d. Whenaperson’sdefencesagainstinfectionarecompromised.

4. Whendothemajorityofpost-operativeinfectionsoccur?a. Withinthefirst12hours.b. Withinthefirst48hours.c. Atthetimeofsurgery.d. Withinthefirst24hours.

5. Endogenous,post-operativeinfectionoccursmostoftenwhenthesurgeryisdoneinwhichofthefollowingconditions?a. Infectioncontrolproceduresarecompromised.b. Patientpresentswithdiabetesmellitus.c. Thereispre-existingperiodontaldisease.d. Thesurgicalsiteisalreadyinfectedwithpatient’sownpathogenicbacteria.


8—AntimicrobiAl ProPhylAxis 119

6. Exogenouswoundinfectionsintheoralcavityarisefrommicroorganismsbeingintroducedduetowhichofthefollowing?a. Lackofthoroughhandwashing.b. Lackofsterilefield.c. Lackofuseofantisepticsinpreparationofoperationsite.d. Non-sterileinstruments.

7. Infectionscanoccurweeksormonthsaftersurgeryandareduetowhichofthefollowing?a. Patientsintroducingbacteriaintothesurgicalsite.b. Latenteffectfollowinguseofnon-sterileinstruments.c. Microorganismsremainingquiescentandthenreactivating.d. Thepatientbecomesimmunocompromised.

8. Anumberofmechanismscouldexplainhowprophylacticantimicrobialsworkandincludewhichofthefollowing?a. Theyformcomplexesthatincreasephagocytosis.b. Theymakeconditionsunfavourabletomicrobialgrowth.c. Theyeliminateopportunisticmicroorganisms.d. Theyarepartiallyeffectiveagainstenvironmentalmicroorganisms.

9. Thenecessityofprophylacticantimicrobialusewithoralsurgicaloperationshasbeenques-tionedduetowhichofthefollowing?a. Endogenousinfectionsarenotaffectedbyantimicrobials.b. Lowincidenceofpost-operativeinfections.c. Highantimicrobialeffectofsaliva.d. Increasedvasculatureintheoralcavityenhancessurgicalwoundhealing.

10. Oneimportantfactortoconsiderwhenselectingtheantimicrobialagentisthatitshouldbeabletodowhichofthefollowing?a. Eliminateallmicroorganismsassociatedwithpost-surgicalinfection.b. Havealonghalf-life.c. Penetratethetissuesconcerned.d. Haveashorthalf-lifetoenhanceclearance.

11. Theabilityofapre-orpost-operativeantimicrobialtopenetratewhichofthefollowingisimportantintheselectionprocess?a. Mucosalsurfaces.b. Bone.c. Softtissue.d. Dentin.

12. Whichofthefollowingagentsdonotadequatelypenetratebone?a. Clindamycin.b. Metronidazole.c. Amoxicillin.d. Cephalosporins.


120 8—AntimicrobiAl ProPhylAxis

13. Maximumconcentrationsofanappropriateantimicrobialagentintheoralskeletalstructuresshouldoccurwithinwhichofthefollowingtimeframes?a. 1hour.b. 6hours.c. 12hours.d. 24hours.

14. Thecurrentconsensusofopinionconcerningtherateofpost-operativeinfectiouscomplica-tionssupportswhichofthefollowingprotocols?a. Prophylacticantimicrobialagentsshouldbeusedwithprudence.b. Routineprophylacticantimicrobialuseisajustifiablepractice.c. Itisbetternottobeconservativewiththeuseofantimicrobials.d. Antimicrobialprophylaxiscannotbejustified.

15. Double-blind randomized trials supportwhichof the following approaches to theuse ofantibioticsduringthirdmolarsurgery?a. Antimicrobialagentsareeffectiveforpatientswithpoororalhygieneundergoingthird

molarsurgery.b. Antimicrobial agents are effective given before and after third molar extractions for

patientswhohaveaveryheavybiofilmpresentthroughoutthemouth.c. Antimicrobial agents have shown no statistically significant effect on post-operative

problemsmostoftenassociatedwiththirdmolarextraction.d. Antimicrobialagentsareeffectivegivenpre-andpost-operativelyforthirdmolarextrac-

tionsinpatientswhopresentwithpericoronitis.

16. Whichistheprincipaloralstreptococcalspeciesisolatedfromcasesofinfectiveendocarditis?a. S. sobrinus.b. S. salivarius.c. S. anginosus.d. S. sanguinis.

17. Therhamnose-richadhesinfoundonstreptococcithatbindsthemtoplateletsandinducesaggregationisknownaswhat?a. LTA.b. PRP.c. PAAP.d. GTF.

18. Ariskassessmentandreviewoftheliteraturerevealswhichofthefollowingwithregardtothelinkbetweendentaltreatmentandtheprovencasesofinfectedjointreplacements?a. Thereisasignificantrelationshipbetweendentaltreatmentandprovencasesofinfected

jointreplacements.b. Apaucityofprovenevidenceshows there isno relationshipbetweendental treatment

andinfectedjointreplacements.c. Thereisaninconclusivelinkbetweendentaltreatmentandprovencasesofinfectedjoint

replacements.d. Ongoingresearch isneededtodeterminetherole thatdental treatmentplays inpost-

operativeinfectedjointreplacements.



19. Aninfectedhipprosthesisrequiringanothersurgicalreplacementoperationhaswhatper-centagechanceofbeingsuccessful?a. 25%.b. 40%.c. 75%.d. 90%.

20. Amoxicillinisapoorchoiceinjointreplacementasaprophylacticantimicrobialforwhichofthefollowingreasons?a. Ithasarelativelyshorthalf-life.b. Ithasnotbeenproventobeeffectiveinpenetratingbonetissue.c. Itmayrarelycauseasevereintestinalcondition.d. Itmayresultinthedevelopmentoforalthrushifusedforprolongedperiodsoftime.

21. Whichofthefollowingexpressestheconclusionsofdouble-blind,placebo-controlled,ran-domized trials on the use of a prophylactic antimicrobial prior to and following implantplacement?a. Ofsignificantclinicalbenefit.b. Equivocalbutprobablynotofuse.c. Strongnegativerelationshiptoimplantsuccess.d. Necessaryforinsurancepurposes.

22. Apotentiallylife-threateningpost-operativeinfectionfollowingdentalproceduresiswhichofthefollowing?a. Cardiacarrhythmia.b. Anginapectoris.c. Cardiacdysrhythmia.d. Infectiveendocarditis.

23. Whichofthefollowingbestdescribesthelikelihoodofalinkbetweeninfectiveendocarditisanddentistry?a. Controversial.b. Confirmed.c. Beingstudied.d. Dependsuponthepatientspresentingcondition.

24. Evenwhenprolongedintravenousantibioticsaregivenpromptlytokilltheinfectingagent,endocarditisstillhasahighmortalityrateofwhichofthefollowing?.a. 5–10%.b. 10–20%.c. 25–40%.d. 50–60%.

25. Whichof the following is the termused todescribebacteria in theblood streamduringdentaltreatment?a. Angina.b. Septicaemia.c. Bloodpoisoning.d. Bacteraemia.



26. Ifapatientexperiencesbacteraemiaduringadentaltreatmentandthebacteriaattachtotheendotheliumoftheheart,whichofthefollowingislikelytooccur?a. Aheartattack.b. Inflammation.c. Athrombolyticevent.d. Sepsis.

27. Theriseinthenumberofpeopledevelopinginfectiveendocarditisduetostaphylococciislikelyduetowhichofthefollowing?a. Useofunsterileneedlesbyintravenousdrugaddicts.b. Increaseinperiodontaldisease.c. Increaseinthenumberofpeoplewhoareundergoingsubgingivalscaling.d. Poororalhygiene.

28. Whichofthefollowingconditionsdoesnotmakepatientsassusceptibletoinfectiveendo-carditisastheothers?a. Acquiredvalvulardamage.b. Valvularinsufficiency.c. Structuralcongenitalheartdisease.d. Cardiomyopathy.

Feedback1. ANS:c

a. Antisepticsarenotagoodalternativetoantibioticsastheyarecommonlynoteffectiveagainstresistantformsofbacteria.

b. Shortertreatmenttimesmaybeineffectual.c. Correct.The empirical overuse of antibiotics has been accompanied by an enormous

increase in the emergence of microbial resistance; this has made some antimicrobialsineffectiveforthetreatmentofsomecommondiseases.

d. Theyshouldbeusedjudiciouslyastheymayexacerbatebacterialresistance.

REF:Antimicrobialagents,p.160

2. ANS:ba. Staphylococci are the most commonly isolated bacterium from cases of infective

endocarditis.b. Correct.Staphylococciarethemostcommonlyisolatedbacteriumfromcasesofinfective

endocarditis.c. Staphylococci are the most commonly isolated bacterium from cases of infective

endocarditis.d. Staphylococci are the most commonly isolated bacterium from cases of infective

endocarditis.

REF:Infectiveendocarditis,Table8.1,pp.163–164



3. ANS:ca. The use of prophylactic antimicrobials is appropriate when the risk of post-operative

infectionishigh.b. The use of prophylactic antimicrobials is appropriate when wounds are contaminated

withsoilordirt (e.g.,after road trafficaccidents)andthere isa riskof infection(e.g.,Clostridium tetani).

c. Correct.Tomeetpatientdemandisnotanappropriatemedicalrationaletorecommendorprescribeamedication.

d. Theuseofprophylacticantimicrobials is appropriatewhenaperson’sdefencesagainstinfectionarecompromised.

REF:Antimicrobialagents,p.160

4. ANS:ca. Themajorityofpost-operativeinfectionsoccuratthetimeofsurgery.b. Themajorityofpost-operativeinfectionsoccuratthetimeofsurgery.c. Correct.Themajorityofpost-operativeinfectionsoccuratthetimeofsurgery.d. Themajorityofpost-operativeinfectionsoccuratthetimeofsurgery.

REF:Whendoespost-operativeinfectionoccur?,pp.160–161

5. ANS:da. Themostcommoncauseofendogenouspost-operativeinfectionisnotnecessarilycom-

promisedinfectioncontrolprocedures.b. Themostcommoncauseofendogenouspost-operativeinfectionisnotnecessarilywhen

asurgicalprocedureisdoneonapatientwithdiabetesmellitus.c. Themostcommoncauseofendogenouspost-operativeinfectionisnotnecessarilywhen

thereispre-existingperiodontaldisease.d. Correct.Themostcommontimewhenendogenouspost-operative infectionoccurs is

when the surgery is done on a site already infectedwith theperson’s ownpathogenicmicroflora.

REF:Whendoespost-operativeinfectionoccur?,p.161

6. ANS:da. Lackofthoroughhandwashingisnotnecessarilyasourceofexogenouscontamination.b. Lackofsterilefieldisnotnecessarilyasourceofexogenouscontamination.c. Lackofuseofantisepticsinpreparationofoperationsiteisnotnecessarilyasourceof

exogenouscontamination.d. Correct.Exogenouswoundinfectionsarisefrommicroorganismsbeingintroducedinto

themouthfromasourceoutsidetheoralcavityandareusuallycausedbypooraseptictechniqueorbynon-sterileinstruments.




7. ANS:ca. Patientsintroducingbacteriaintothesurgicalsiteisnotnecessarilyhowlateinfections

occur.b. Theuseofnon-sterileinstrumentswouldnotbethecauseoflateinfections.c. Correct.Lateinfectionscanoccurweeksormonthsaftertheoperationandaredueto

thereactivationofmicroorganismsthathaveremainedquiescentwithinthesite.d. Apatientbecoming immunocompromised isnot thecauseof theoccurrenceof a late

infection.


8. ANS:aa. Correct.Antimicrobialscanattachtothesurfaceofthemicroorganismsandformcom-

plexes that increasephagocytosis, and couldbe an explanation as tohowprophylacticantimicrobialswork.

b. Makingconditionsunfavourabletomicrobialgrowthwouldnotnecessarilyexplainhowprophylacticantimicrobialswork.

c. Eliminatingopportunisticmicroorganismswouldnotnecessarilyexplainhowprophylac-ticantimicrobialswork.

d. Thisstatementisnotamechanismtoexplainhowprophylacticantibioticswork.

REF:Howdoespre-surgicalantimicrobialprophylaxiswork?,p.161

9. ANS:ba. Endogenousinfections,determinedbythelevelofpre-surgicalmicroflora,mayormay

notsupporttheuseofprophylacticantimicrobials.b. Correct.Withoralsurgicaloperationswheretheincidenceofpost-operativeinfection

isverylowthereisthequestionastowhetherantimicrobialprophylaxisisnecessaryatall.

c. Salivadoesnothaveahighanti-microbialeffect.d. Increased vasculature in the oral cavity enhances surgical wound healing but may not

effectivelydealwithmicrobialattack.

REF:Antimicrobialprophylaxisfororalsurgery,p.162

10. ANS:ca. Itisnotpossibleforanyanti-microbialtototallyeliminateallmicro-organismsassociated

withpost-surgicalinfection.b. Anantimicrobial’sspecifichalf-lifemayhavenoimpactontheselectionoftheantimi-

crobialagenttobeused.c. Correct.Oneimportantfactortoconsiderwhenselectingtheantimicrobialagentisits

abilitytopenetratethetissuesconcerned.d. Ashorthalf-lifewouldreducetheeffectivenessofanantibiotic.




11. ANS:ba. Bone is the most important tissue when it comes to the selection of an appropriate

antimicrobialagent,notmucosalsurfaces.b. Correct.Oneimportantfactortoconsiderwhenselectingtheantimicrobialagentisthat

itshouldbeabletopenetratethetissuesconcernedandinparticularbone.c. Bone is the most important tissue when it comes to the selection of an appropriate

antimicrobial,notsofttissue.d. Bone is the most important tissue when it comes to the selection of an appropriate

antimicrobial,notdentin.


12. ANS:ca. Clindamycinpenetratesbonewell.b. Metronidazolepenetratesbonewell.c. Correct.Amoxicillindoesnotpenetratebonewell.d. Cephalosporinspenetratebonewell.


13. ANS:aa. Correct.Mostantimicrobialagentsthatpenetratebonedosorapidlyintheoralskeletal

structuresusuallyattainingmaximalconcentrationswithinonehour.b. Mostantimicrobialagentsthatpenetratebonedosorapidlyintheoralskeletalstructures

usuallyattainingmaximalconcentrationswithinonehour.c. Mostantimicrobialagentsthatpenetratebonedosorapidlyintheoralskeletalstructures

usuallyattainingmaximalconcentrationswithinonehour.d. Mostantimicrobialagentsthatpenetratebonedosorapidlyintheoralskeletalstructures

usuallyattainingmaximalconcentrationswithinonehour.


14. ANS:da. Thecurrentconsensusofopinionisthattherateofpost-operativeinfectiouscomplica-

tionsissolowthatantimicrobialprophylaxiscannotbejustifiedandwouldnotaffecttheoutcome.

b. Thecurrentconsensusofopinionisthattherateofpost-operativeinfectiouscomplica-tionsissolowthatantimicrobialprophylaxiscannotbejustifiedandwouldnotaffecttheoutcome.

c. Thecurrentconsensusofopinionisthattherateofpost-operativeinfectiouscomplica-tionsissolowthatantimicrobialprophylaxiscannotbejustifiedandwouldnotaffecttheoutcome.

d. Correct.Thecurrentconsensusofopinionisthattherateofpost-operativeinfectiouscomplicationsissolowthatantimicrobialprophylaxiscannotbejustifiedandwouldnotaffecttheoutcome.

REF:Antimicrobialprophylaxisfororalsurgery,p.162



15. ANS:ca. Therehasbeennostatisticallysignificantevidencethatantimicrobialagentsgivenbefore

andafterthirdmolarextractionareofclinicalbenefit.b. Therehasbeennostatisticallysignificantevidencethatantimicrobialagentsgivenbefore

andafterthirdmolarextractionareofclinicalbenefit.c. Correct.Therehavebeenninedouble-blindrandomizedtrialsofavarietyofprophylactic

antimicrobialagentsgivenbeforeandafterthirdmolarsurgery.Allofthesetrialshavecome to the sameconclusion that antimicrobial agentshaveno statistically significanteffectonswelling,pain,trismusorpost-operativeinfection.

d. Therehasbeennostatisticallysignificantevidencethatantimicrobialagentsgivenbeforeandafterthirdmolarextractionareofclinicalbenefit.

REF:Thirdmolarsurgery,p.162

16. ANS:da. Strep. sanguinisisthemostcommonlyisolatedstreptococcalspeciesisolatedfromcases

ofinfectiveendocarditis.b. Strep. sanguinisisthemostcommonlyisolatedstreptococcalspeciesisolatedfromcases

ofinfectiveendocarditis.c. Strep. sanguinisisthemostcommonlyisolatedstreptococcalspeciesisolatedfromcases

ofinfectiveendocarditis.d. Correct. Strep. sanguinis is the most commonly isolated streptococcal species isolated

fromcasesofinfectiveendocarditis.

REF:Infectiveendocarditis,Table8.1,p.164

17. ANS:aa. LTA is lipoteichoic acid, and is found on the bacterial surface, but is not involved in

plateletaggregation.b. PRPisaproline-richrichpeptidefoundinsaliva.c. Correct.PAAPisplateletaggregatingprotein.d. GTFisaglucosyltransferasewhichmakesglucanaspartoftheplaquematrix.

REF:Infectiveendocarditis,p.164

18. ANS:ba. A risk assessment and reviewof the literature reveals apaucityofproven caseswhere

infectedjointreplacementprostheseshavebeenlinkedwithdentaltreatment.b. Correct.Ariskassessmentandreviewoftheliteraturerevealsapaucityofprovencases

whereinfectedjointreplacementprostheseshavebeenlinkedwithdentaltreatment.c. A risk assessment and reviewof the literature reveals apaucityofproven caseswhere

infectedjointreplacementprostheseshavebeenlinkedwithdentaltreatment.d. A risk assessment and reviewof the literature reveals apaucityofproven caseswhere

infectedjointreplacementprostheseshavebeenlinkedwithdentaltreatment.

REF:Jointreplacement,p.162



19. ANS:aa. Correct.Aninfectedhipprosthesiswouldrequireanothersurgicalreplacementoperation

andhasanapproximately25%chanceofbeingsuccessful,thusapersonhasonlya25%chanceofbeingabletosatisfactorilywalkagain.

b. No;apersonwithaninfectedhiphasa25%chanceofbeingabletowalksatisfactorilyagain.

c. No;apersonwithaninfectedhiphasa25%chanceofbeingabletowalksatisfactorilyagain.

d. No;apersonwithaninfectedhiphasa25%chanceofbeingabletowalksatisfactorilyagain.


20. ANS:ba. Amoxicillinisnotanappropriatechoiceasaprophylacticantimicrobialinjointreplace-

mentbecauseitnotbeenproventobeeffectiveinpenetratingbone.b. Correct.Amoxicillinisapoorchoiceinthisparticularcircumstanceasithasnotbeen

proventobeeffectiveinpenetratingbone.c. Amoxicillinisapoorchoiceinthisparticularcircumstanceasithasnotbeenprovento

beeffectiveinpenetratingbone.d. Amoxicillinisapoorchoiceinthisparticularcircumstanceasithasnotbeenprovento

beeffectiveinpenetratingbone.


21. ANS:ba. Atleastninesubstantialdouble-blindplacebocontrolledrandomizedtrialsontheuseof

prophylacticantimicrobialsandimplantplacementhavefound,atbest,equivocalresults.b. Correct.Therehavenowbeenatleastninesubstantialdouble-blindplacebocontrolled

randomizedtrialsontheuseofprophylacticantimicrobialsandimplantplacementthatfindtheiruseatbestequivocal,but‘probablynotofuse’.

c. Atleastninesubstantialdouble-blindplacebocontrolledrandomizedtrialsontheuseofprophylacticantimicrobialsandimplantplacementhavefound,atbest,equivocalresults.

d. Insurancedoesnotdictatetheuseofprophylacticantimicrobialsforimplantplacementprocedures.

REF:Dentalimplants,pp.162–163

22. ANS:da. Cardiacarrhythmiaisnotapost-operativeinfection.b. Anginapectorisisnotapost-operativeinfection.c. Cardiacdysrhythmiaisnotapost-operativeinfection.d. Correct.Onepotentialpost-operativeinfectionfollowingdentalproceduresthatcould

beseriousandlife-threateningisinfectiveendocarditis.

REF: Oral surgery where the consequences of post-operative infection are potentiallyserious,p.163



23. ANS:aa. Correct.Thelinkbetweenthisinfectionanddentistryishighlycontroversial,asisthe

useofantimicrobialprophylaxistopreventthiscondition.b. The link between this infection and dentistry is highly controversial, as is the use of

antimicrobialprophylaxistopreventthiscondition.c. The link between this infection and dentistry is highly controversial, as is the use of

antimicrobialprophylaxistopreventthiscondition.d. The link between this infection and dentistry is highly controversial, as is the use of

antimicrobialprophylaxistopreventthiscondition.

REF:Antimicrobialprophylaxisagainstinfectiveendocarditis,p.165

24. ANS:ca. Even when prolonged intravenous antibiotics are given promptly to kill the infecting

agent,endocarditisstillhasahighmortalityrateof25–40%.b. Even when prolonged intravenous antibiotics are given promptly to kill the infecting

agent,endocarditisstillhasahighmortalityrateof25–40%.c. Correct. Even when prolonged intravenous antibiotics are given promptly to kill the

infectingagent,endocarditisstillhasahighmortalityrateof25–40%.d. Even when prolonged intravenous antibiotics are given promptly to kill the infecting

agent,endocarditisstillhasahighmortalityrateof25–40%.


25. ANS:da. Anginaischestpainduetoischaemiaoftheheartmuscle.b. Septicaemiaisapotentiallyfatalwhole-bodyinflammationcausedbysevereinfection.c. Bloodpoisoning,sepsis,isapotentiallyfatalwhole-bodyinflammationcausedbysevere

infection.d. Correct.Bacteraemiaisthetermusedwhenbacteriaenterthebloodstream.


26. ANS:ba. Bacteraemiasdonotincreasetheriskofheartattacks.b. Correct. If bacteria enter the blood stream they can cause inflammation of the heart

endotheliumfromwhichinfectiveendocarditiscanensue.c. Bacteraemiasdonotincreasetheriskofthrombolyticevents.d. Sepsisisnotlikelytooccursubsequenttobacteraemiafromdentaltreatment.




27. ANS:aa. Correct. The rise in the number of people developing infective endocarditis due to

staphylococciisprobablyduetouseofunsterileneedlesbyintravenousdrugaddicts.b. Theriseinthenumberofpeopledevelopinginfectiveendocarditisduetostaphylococci

isunrelatedtoanincreaseinperiodontaldisease.c. Theriseinthenumberofpeopledevelopinginfectiveendocarditisduetostaphylococci

isunrelatedtosubgingivalscalingprocedures.d. Theriseinthenumberofpeopledevelopinginfectiveendocarditisduetostaphylococci

isunrelatedtopoororalhygiene.


28. ANS:ba. Therearefourgroupsofpatientswhoareparticularlysusceptibletoinfectiveendocarditis;

thesearethosewithacquiredvalvulardamage,structuralcongenitalheartdisease,valvereplacementsandcardiomyopathy.

b. Correct.Patientswithvalvularinsufficiencyarenotamongthesusceptiblegroups.c. Therearefourgroupsofpatientswhoareparticularlysusceptibletoinfectiveendocarditis;

thesearethosewithacquiredvalvulardamage,structuralcongenitalheartdisease,valvereplacementsandcardiomyopathy.

d. Therearefourgroupsofpatientswhoareparticularlysusceptibletoinfectiveendocarditis;thesearethosewithacquiredvalvulardamage,structuralcongenitalheartdisease,valvereplacementsandcardiomyopathy.

REF:Antimicrobialprophylaxisagainstinfectiveendocarditis,p.165


130

C H A P T E R 9

Oral Fungal Infections

Multiple Choice1. Whichoneofthefollowingfungalgeneraisconsideredtobeanormalresidentintheoral

cavityofhealthyindividuals?a. Saccharomyces.b. Candida.c. Geotrichum.d. Cryptococcus.

2. WhenconditionsinthemouthfavourtheproliferationofCandida,whichoneofthefol-lowingwillmostlikelyoccur?a. Salivaryflowreduces.b. Dentalcariesareinitiated.c. Oralcandidosismaydevelop.d. Dentalplaquelevelsincrease.

3. ThetermCandidaoriginatesfromtheLatinwordcandidus,meaningwhichofthefollowing?a. Disease.b. Inflammation.c. White.d. Fungi.

4. WhichofthefollowingisgenerallythemostprevalentCandidaspeciesrecoveredfromthehumanmouthinbothcommensalstateandcasesoforalcandidosis?a. Candida glabrata.b. Candida tropicalis.c. Candida albicans.d. Candida guilliermondii.

5. Whichoneofthefollowingisafactormostlikelytobeassociatedwithpromotingcolonisa-tionofCandidaintheoralcavity?a. Antibioticresistance.b. Sloughingofepithelialcellsfromtheoralmucosa.c. Non-specificadherenceprocess.d. Abilitytoreleasecytokines.

6. Which one of the following host factors is not associated with the development of oralcandidosis?a. Reducedsalivaryflow.b. Thewearingofadenture.c. Thereceiptofabroad-spectrumantibiotic.d. Increasedsalivaryflow.


9—Oral Fungal InFectIOns 131

7. WhichoneofthefollowingisakeyvirulencefactorofC. albicans?a. Beta-lactamaseproduction.b. Abilitytosecretehydrolyticenzymes.c. Productionofendotoxins.d. GrowthofC. albicansinayeastformonly.

8. C. albicanshas theability togrow in severalmorphological states includingwhichoneofthefollowing?a. Spirochaetes.b. Periplasmicflagella.c. Cystatins.d. Hyphae.

9. DestructionofhosttissuesbyCandidamaybefacilitatedbywhichoneofthefollowing?a. Presenceofiron-freelactoferrin.b. Salivaryperoxidaseenzymes.c. Presenceofdefensins.d. Releaseofhydrolyticenzymes.

10. One pathological effect of secreted aspartyl proteinases (SAPs) is due to which of thefollowing?a. Enhanceddegradationofdietarysugars.b. Anabilitytodegradehostextracellularmatrixproteins.c. Anabilitytokillcompetingbacteriaintheoralcavity.d. Anabilitytodegradephospholipidsinhostcellmembranes.

11. Phospholipasesareenzymesthathydrolysephospholipidsintowhichofthefollowing?a. Formate.b. Fattyacids.c. Lacticacids.d. Aminoacids.

12. A high incidence of oral candidosis is found primarily in which of the following patientpopulations?a. Patientswithhighcariesrates.b. Casesofcervicofacialactinomycosis.c. Patients who are human immunodeficiency virus (HIV) positive and suffering from

acquiredimmunodeficiencysyndrome.d. Patientswhosufferfromherpessimplexvirusinfection.

13. Four distinct primary oral candidoses are frequently described based on which of thefollowing?a. Pyrexia.b. Clinicalpresentation.c. Xerostomia.d. Halitosis.


132 9—Oral Fungal InFectIOns

14. Acuteerythematouscandidosisischaracterisedbythepresenceofwhichofthefollowing?a. Lichenplanus.b. Pseudomembranes.c. Submandibularswelling.d. Painfulreddenedpatches.

15. Acuteerythematouscandidosis ismost frequentlyassociatedwith theadministrationofabroad-spectrum antibiotic, and particularly if the patient also uses which one of thefollowing?a. Antimicrobialrinse.b. Warmsaltwaterrinse.c. Vinegarrinse.d. Steroidinhaler.

16. Broadspectrumantibioticsdecreasethebacterialcommunitywithintheoralcavity,poten-tiallyresultinginwhichofthefollowing?a. Formationofgranulationtissue.b. Suppurativeparotitis.c. AnincreaseinthenumberofCandida.d. Inflammationofthesalivaryglands.

17. A patient with chronic hyperplastic candidosis is most likely to be which one of thefollowing?a. Onantibiotictherapy.b. Asmoker.c. Usinganantimicrobialrinse.d. Sufferingfromperiodontaldisease.

18. Whenleftuntreated,chronichyperplasticcandidosiscanprogresstodysplasiaand,subse-quently,whichofthefollowing?a. Oralcancer.b. Lichenplanus.c. Periodontaldisease.d. Herpessimplexvirusinfection.

19. Chronichyperplasticcandidosiscanoccuratanysiteontheoralmucosa,butismostfre-quentlyencounteredasbilateralwhitepatchesinwhichofthefollowingareas?a. Vestibularmucosa.b. Vermillionborder.c. Dorsumofthetongue.d. Buccalcommissureregions.

20. Chronichyperplasticcandidosispresentsastwolesionaltypes:homogeneouslesionsthataresmoothandwhite,whichcontrastwithheterogeneouslesions,whichappearaswhichofthefollowing?a. Smoothandglossy.b. Nodularorspeckled.c. Inflamed.d. Areasofpseudomembranedevelopment.



21. Whichofthefollowingtypesofchronichyperplasticcandidosisaremorepronetomalignanttransformation?a. Heterogeneous.b. Symmetrical.c. Homogeneous.d. Erythematous.

22. In addition to the primary forms of oral candidosis, which one of the following may besecondaryCandida-associatedlesions?a. Herpessimplextype1(HSV-1)infection.b. Periodontalinfection.c. Angularcheilitis.d. Lichenplanus.

23. Angularcheilitischaracteristicallypresentsaserythematouslesionslocatedatwhichoftheselocationsintheoralcavity?a. Vestibularmucosa.b. Dorsumofthetongue.c. Cornersofthemouth.d. Vermillionborder.

24. Median rhomboid glossitis is seen as a symmetrical shaped area located in which of thefollowingareasintheoralcavity?a. Vestibularmucosa.b. Vermillionborder.c. Cornersofthemouth.d. Dorsumofthetongue.

25. Thekeypredisposingfactortoanumberofrelativelyrarecongenitalconditionsassociatedwithchronicmucocutaneouscandidosiscentreonwhichofthefollowing?a. HSV-1infection.b. Historyofsmoking.c. Impairedcellularimmunity.d. Diabetes.

26. ThereareawidevarietyofphenotypicmethodsroutinelyusedtoidentifyisolatedCandidaincludingwhichoneofthefollowing?a. Pulsedfieldgelelectrophoresis.b. RandomamplifiedpolymorphicDNA.c. Biochemicalprofiling.d. Inter-repeatsequenceamplification.

27. Oralcandidosesareopportunisticinfectionsandassucharisewhenwhichoneofthefol-lowingoccurs?a. Hostdebilitation.b. DevelopmentofantifungalresistancebycolonisingCandida.c. Bacterialnumbersincreaseintheoralcavity.d. Infectionwithherpessimplexvirus.



28. Undiagnosedorpoorlycontrolleddiabetesisarecognisedpredisposingfactortooralcan-didosisandthereforeassessmentofwhichofthefollowingmayberequired?a. Bilirubin.b. Bloodglucose.c. Albumin.d. Serumactivityofalanineaminotransferase(ALT).

29. Whichoneofthefollowingisareasonthatincomparisontoantibiotics,thedevelopmentofnewantifungalagentshasbeenrelativelylimited?a. Difficultiesofantifungalsusceptibilitytesting.b. Difficultyinidentifyingsuitablefungaltargetsthatareabsentfromhostcells.c. Relativecostsassociatedwithantifungalproduction.d. Broadspectrumantibioticseffectiveagainstbacteriaalsotendtoinhibitfungi.

30. Whichofthefollowinghasbeenusedasasystemicantifungaltherapyfortreatingprimaryformsoforalcandidosis?a. Nystatin.b. Clotrimazole.c. 5-Flucytosine.d. Miconazole.

31. Enhancedoccurrenceofwhichoneofthefollowingisareasonthathascontributedtogreaterincidenceofcandidoses?a. HSV-1infection.b. Oralcancer.c. Immunosuppressivetherapies.d. Useofdentalimplants.

32. An example of a host predisposing factor leading to oral candidosis is which one of thefollowing?a. Useofsteroidinhalers.b. Useofantiviraltherapy.c. Useofantimicrobialmouthrinses.d. Herpessimplexvirusinfection.

33. In denture wearers who have chronic erythematous candidosis which of the following isparamounttothemanagementofthiscondition?a. Improvementofdenturehygiene.b. Reducingcarbohydrateintake.c. Antibiotictherapy.d. Reducingalcoholconsumption.

34. Whichoneofthefollowingisanantimicrobialpeptidethatislargelyspecifictothemouthandhasanti-candidalactivity?a. Defensins.b. Mucins.c. Histatins.d. Transferrins.



Feedback1. ANS:b

a. Saccharomyces are fungi that are not frequently encountered in the mouth of healthyindividuals.

b. Correct.Candidaarefungifrequentlyencounteredinthemouthsofhealthyindividuals,andassuchareconsideredtobenormalresidentsintheoralcavity.

c. Geotrichum are fungi that are not frequently encountered in the mouths of healthyindividuals.

d. Cryptococcus are fungi that are not frequently encountered in the mouths of healthyindividuals.

REF:PathogenicCandidaspecies,p.166

2. ANS:ca. AreducedsalivaryflowmaypromoteCandidaproliferationbutdoesnotfollowincreased

Candidaproliferation.b. DentalcariesdonotoccurasaresultofincreasedCandidanumbers.c. Correct.WhileCandidaspeciesarenormallyharmless,whenconditionsinthemouth

altertofavourproliferationofCandida,oralcandidosiscanoccur.d. Dentalplaqueismainlycomprisedofbacteriaandassuchitslevelsarenotnecessarily

affectedbyconditionspromotingCandidagrowth.

REF:Candidavirulencefactors,p.167

3. ANS:ca. The term Candida originates from the Latin word candidus, which means white, not

disease.b. The term Candida originates from the Latin word candidus, which means white, not

inflammation.c. Correct.ThetermCandidaoriginatesfromtheLatinwordcandidus,meaningwhite.d. The term Candida originates from the Latin word candidus, which means white, not

fungi.


4. ANS:ca. C. albicans not C. glabrata is the most prevalent Candida species recovered from the

humanmouth.b. C. albicans not C. tropicalis is the most prevalent Candida species recovered from the

humanmouth,inbothcommensalstateandcasesoforalcandidosis.c. Correct.Generally,themostprevalentCandidaspeciesrecoveredfromthehumanmouth

inbothcommensalstateandcasesoforalcandidosisisC. albicans.d. C. albicansnotC. guilliermondiiisthemostprevalentCandidaspeciesrecoveredfromthe

humanmouthinbothcommensalstateandcasesoforalcandidosis.




5. ANS:ca. AntibioticresistanceisnotafactorthatgenerallypromotesCandidacolonisationofthe

oralcavity.b. Sloughingofepithelialcellsfromtheoralmucosaactuallyisahostdefencemechanism

thatpromotesremovalofCandidafromtheoralcavity.c. Correct.Thenon-specificadherenceprocessisafactorthatallowsCandidatoinitially

adheretosurfacesintheoralcavity.d. TheabilitytoreleasecytokinesisnotafactorthatpromotesCandidacolonisationofthe

oralcavity.


6. ANS:da. Reducedsalivaryflowisahostfactorcontributingtooralcandidosis.b. ThewearingofadentureisassociatedwithpromotingCandidacolonisationoftheoral

cavityandmaypromoteoralcandidosis.c. Receiptofabroad-spectrumantibiotic lowersbacterialnumbersandcancontributeto

thedevelopmentoforalcandidosis.d. Correct.IncreasedsalivaryflowcanlowerCandidanumbersbypromotingtheirphysical

removalfromoralsurfaces.


7. ANS:ba. Beta-lactamaseproductionisnotavirulencefactorofC. albicans.b. Correct.OneofthekeyvirulencefactorsofC. albicansisitsabilitytosecretehydrolytic

enzymesthatdamagehostcells.c. ProductionofendotoxinsisnotakeyvirulencefactorofC. albicans.d. GrowthofCandidainayeastformisnotavirulencefactorofC. albicans.


8. ANS:da. Spirochaetesarea classofbacteriapartlydefinedby their characteristic coiledcellular

morphology;itisnotaCandidamorphology.b. Periplasmicflagellaareappendagesformedonthesurfacesofcertainbacteria.c. CystatinsareafamilyofcysteineproteaseinhibitorsandnotaCandidamorphology.d. Correct.C. albicanshastheabilitytogrowashyphae.

REF:Morphology,p.168

9. ANS:da. DestructionofhosttissuesbyCandidamaybefacilitatedbyreleaseofhydrolyticenzymes

intothelocalenvironment,notbythepresenceofiron-freelactoferrin.b. Thepresenceofsalivaryperoxidaseenzymesisnotafactorofhosttissuedestructionby

Candida.c. DestructionofhosttissuesbyCandidaisnotfacilitatedbythepresenceofdefensins.d. Correct.DestructionofhosttissuesbyCandidamaybefacilitatedbyreleaseofhydrolytic

enzymesbyCandidaintothelocalenvironment.

REF:Hydrolyticenzymes,p.168



10. ANS:ba. Proteinasesdonothydrolysesugarsandthisisthereforenotafactorinvirulence.b. Correct. The exact role of secreted aspartyl proteinases (SAPs) in virulence remains

unclear;however,theirabilitytodegradehostextracellularmatrixproteinsisthoughttobeapathogenicfactor.

c. The role of secreted aspartyl proteinases (SAPs) in virulence appears related to theirabilitytodegradehostextracellularmatrixproteins.TheseSAPsdonothavetheabilitytokillcompetingbacteriaintheoralcavity.

d. DegradationofphospholipidsinhostcellmembranesismediatedbyphospholipasesandnotSAPs.

REF:Secretedaspartylproteinases(SAPs),p.168

11. ANS:ba. Phospholipasesareenzymesthathydrolysephospholipidsnotintoformate,butintofatty

acids.b. Correct.Phospholipasesareenzymesthathydrolysephospholipidsintofattyacids.c. Phospholipasesareenzymesthathydrolysephospholipidsnotintolacticacids,butinto

fattyacids.d. Phospholipasesareenzymesthathydrolysephospholipidsnotintoaminoacids,butinto

fattyacids.

REF:Phospholipases,p.168

12. ANS:ca. Dentalcariesarenotassociatedwithincidencesoforalcandidosis.b. Oralcandidosisincidenceisnotassociatedwithcervicofacialactinomycosis.c. Correct. High incidence of oral candidosis is found in HIV-positive individuals and

thosesufferingfromacquiredimmunodeficiencysyndrome.d. Patientswhosufferfromherpessimplexvirusinfectionarenotatincreasedriskoforal

candidosis.

REF:Oralcandidosis,p.169

13. ANS:ba. Fourdistinct,primaryoralcandidosesarefrequentlydescribed,basednotuponthepres-

enceofpyrexia,butonclinicalpresentation.b. Correct.Oralcandidosisisnotasingleentityandfourdistinctprimaryoralcandidoses

arefrequentlydescribedbasedonclinicalpresentation.c. Fourdistinctprimaryoralcandidosesarefrequentlydescribed,baseduponclinicalpres-

entation,notonthepresenceofxerostomia.d. Fourdistinctprimaryoralcandidosesarefrequentlydescribed,baseduponclinicalpres-

entation,notonthepresenceofhalitosis.




14. ANS:da. Lichenplanusappearsontheoralmucosamostlyaswhitelesions;itisaconditionthat

isnotthoughttobecausedbyCandida.b. Pseudomembranouscandidosisisaformoforalcandidosisthatpresentsaswhiteplaque-

likepseudomembranes.c. Acuteerythematouscandidosisisnotcharacterisedbysubmandibularswelling.d. Correct.Acuteerythematouscandidosisischaracterisedbythepresenceofpainfulred-

denedpatchesontheoralmucosa,typicallyonthedorsumofthetongue.

REF:Acuteerythematouscandidosis,pp.169–170

15. ANS:da. Acuteerythematouscandidosisisnotexacerbatedbytheuseofanantimicrobialrinse.b. Awarmsaltwaterrinsedoesnotexacerbateacuteerythematouscandidosis.c. Acuteerythematouscandidosisismostfrequentlyassociatedwiththeadministrationof

abroadspectrumantibiotic,butnotwithanadjunctivevinegarrinse.d. Correct.Acuteerythematouscandidosisismostfrequentlyassociatedwiththeadmin-

istration of a broad spectrum antibiotic, particularly if the patient also uses a steroidinhaler.

REF:Acuteerythematouscandidosis,Table9.3,pp.169–171

16. ANS:ca. Itisbelievedthattheantibioticdecreasesthebacterialcommunitywithintheoralmicro-

flora,whichmay result inan increase inCandida,not in the formationofgranulationtissue.

b. Itisbelievedthattheantibioticdecreasesthebacterialcommunitywithintheoralmicro-flora,whichmayresultinanincreaseinCandida,butnotinsuppurativeparotitis.

c. Correct.Itisbelievedthattheantibioticdecreasesthebacterialcommunitywithintheoralmicroflora,allowingCandidanumberstoincreaseduetoreducedcompetition.

d. Itisbelievedthattheantibioticdecreasesthebacterialcommunitywithintheoralmicro-flora,whichdoesnotresultininflammationofthesalivaryglands.

REF:Acuteerythematouscandidosis,p.171

17. ANS:ba. Apatientwithchronichyperplasticcandidosisisnotnecessarilyonantibiotictherapy.b. Correct.Arepresentativepatientwithchronichyperplasticcandidosisisoftenamiddle-

agedsmoker.c. Arepresentativepatientwithchronichyperplasticcandidosisisnotnecessarilyusingan

antimicrobialrinse.d. Apatientwithchronichyperplasticcandidosisisnotnecessarilyalsosufferingfromperi-

odontaldisease.

REF:Chronichyperplasticcandidosis,p.171



18. ANS:aa. Correct.Ifleftuntreated,somecasesofchronichyperplasticcandidosis(5–10%)progress

toexhibitdysplasiawithsubsequentdevelopmentoforalcancer.b. Chronichyperplasticcandidosiswillnotdevelopintolichenplanus.c. Chronic hyperplastic candidosis if left untreated can subsequently develop into oral

cancerandnotperiodontaldisease.d. Chronichyperplasticcandidosisisgenerallyasymptomaticandifleftuntreateddoesnot

developintoherpessimplexvirusinfection.


19. ANS:da. Chronic hyperplastic candidosis can occur at any site on the oral mucosa but is most

frequentlyencounteredasbilateralwhitepatchesinthebuccalcommissureregions,notthevestibularborder.

b. Chronic hyperplastic candidosis can occur at any site on the oral mucosa but is mostfrequentlyencounteredasbilateralwhitepatchesinthebuccalcommissureregions,notthevermillionborder.

c. Chronichyperplasticcandidosiscanoccuratanysiteontheoralmucosaandmostcom-monlyinthebuccalcommissureregions.

d. Correct.Chronichyperplasticcandidosiscanoccuratanysiteontheoralmucosabutismostfrequentlyencounteredasbilateralwhitepatchesinthebuccalcommissureregions.


20. ANS:ba. Heterogeneouslesionsappearasareasoferythema,givinganodularorspeckledappear-

ance,notsmoothandglossy.b. Correct.Heterogeneouslesionsappearasareasoferythema,givinganodularorspeckled

appearance.c. Heterogeneouslesionsappearasareasoferythema,givinganodularorspeckledappear-

ance,butnotnecessarilyinflamed.d. Heterogeneouslesionsappearasareasoferythema,givinganodularorspeckledappear-

ance,butnotasareasofpseudomembranedevelopment.


21. ANS:aa. Correct.Heterogeneouslesionsaremorepronetomalignanttransformation.b. Theshapeofthechronichyperplasticcandidosislesionisnotindicativeofamalignant

formation.c. Ofthelesiontypesofchronichyperplasticcandidosis,thehomogeneouslesionsareless

pronetomalignanttransformationcomparedwithheterogeneouslesions.d. Ofthelesiontypesoforalcandidosis,erythematouslesionsarenotmorepronetomalig-

nanttransformation.




22. ANS:ca. Candida-associatedlesionsdonotincludethosecausedbyHSV-1.b. PseudomembranouscandidosisisaprimaryformofCandidainfection.c. Correct.Inadditiontotheprimaryformsoforalcandidosisdescribed,otherCandida-

associatedlesionsarerecognisedandincludeconditionssuchasangularcheilitis.d. Candida-associatedlesionsdonotincludelichenplanus.

REF:Othersecondaryformsoforalcandidosis,p.171

23. ANS:ca. Angularcheilitisdoesnotcharacteristicallypresentaserythematouslesionsintheves-

tibularmucosalarea.b. Angular cheilitis does not characteristically present as erythematous lesions on the

dorsumofthetongue.c. Correct. Angular cheilitis characteristically presents as erythematous lesions at the

cornersofthemouth.d. Angular cheilitis characteristically presents as erythematous lesions at the vermillion

border.


24. ANS:da. Median rhomboidglossitis is seenasa symmetrical shapedarea in themidlineof the

dorsumofthetongueandnotatthevestibularmucosa.b. Medianrhomboidglossitis isseenasasymmetricalshapedareaonthemidlineofthe

dorsumofthetongueandnotatthevermillionborder.c. Medianrhomboidglossitis isseenasasymmetricalshapedareaonthemidlineofthe

dorsumofthetongueandnotatthecornersofthemouth.d. Correct.Medianrhomboidglossitisisseenasasymmetricalshapedarealocatedinthe

midlineofthedorsumofthetongue.

REF:Medianrhomboidglossitis,p.171

25. ANS:ca. Anumberofrelativelyrarecongenitalconditionsareassociatedwithchronicmucocuta-

neouscandidosisandthekeypredisposingfactorwouldappearnottocentreonahistoryofHSV-1butonimpairedcellularimmunity.

b. Anumberofrelativelyrarecongenitalconditionsareassociatedwithchronicmucocuta-neouscandidosisandthekeypredisposingfactorwouldnotappeartocentreonsmokinghistory,butonimpairedcellularimmunity.

c. Correct.Anumberofrelativelyrarecongenitalconditionsareassociatedwithchronicmucocutaneous candidosis and the key predisposing factor would appear to centre onimpairedcellularimmunity.

d. Anumberofrelativelyrarecongenitalconditionsareassociatedwithchronicmucocuta-neouscandidosisandthekeypredisposingfactorwouldappearnottocentreonahistoryofdiabetesbutonimpairedcellularimmunity.

REF:Chronicmucocutaneouscandidosis,pp.171–172



26. ANS:ca. Pulsedfieldgelelectrophoresisisagenotypicmethodlargelyreservedforepidemiological

investigationsinresearchoforalcandidosis.b. RandomamplifiedpolymorphicDNAisagenotypicmethodlargelyreservedforepide-

miologicalinvestigationsinresearchoforalcandidosis.c. Correct.BiochemicalprofilingisaphenotypicapproachoftenusedtoidentifyCandida

isolates.d. Inter-repeatsequenceamplificationisagenotypicmethodthatcanbeusedforepidemio-

logicalinvestigations.

REF:Summary,p.176

27. ANS:aa. Correct.Opportunistic infectionsgenerallyarisewhenthehostbecomesweakenedor

debilitatedthusimpedingnormalhostdefences.b. Acquisitionofresistancetoantifungalagentsdoesnotleadtoinitiationofopportunistic

infection.c. Oralcandidosisisafungalinfectionandthereforedoesnotoccurwhenbacterialnumbers

increase.d. HerpessimplexvirusinfectionisnotimplicatedinopportunisticinfectionbyCandida.

REF:Managementoforalcandidosis,p.176

28. ANS:ba. Bilirubinisnotadiagnostictestusedtoassessdiabetes.b. Correct.Undiagnosedorpoorlycontrolleddiabetesisarecognisedpredisposingfactor

tooralcandidosisandthereforeassessmentofbloodglucosemayberequired.c. Albuminisnotadiagnostictestusedtoassessdiabetes.d. SerumactivityofALTisnotadiagnostictestusedtoassessdiabetes.


29. ANS:ba. Difficultyoftestingtechniqueisnotareasonthatthedevelopmentofantifungalagents

hasbeenrelativelylimited.b. Correct.Sincefungiareeukaryoticcellstheysharemanycharacteristicswithmammalian

cells;assuch,problemsdoariseinidentifyingsuitablefungaltargetsthatareabsentfromhostcells.

c. Relative cost of antifungaldevelopment comparedwith thoseof antibiotics isnot thereasonforcomparativelylimitedantifungaldevelopment.

d. Antibioticstargetingbacteriadonottendtobeactiveagainstfungi.

REF:Antifungalintervention,p.176



30. ANS:ca. Nystatinisatopicalantifungalagent.b. Clotrimazoleisatopicalantifungalagent.c. Correct.5-Flucytosineisasystemicantifungalagent.d. Miconazoleisatopicalantifungalagent.

REF:Polyeneantifungals,Table9.5,p.177

31. ANS:ca. It is not an increase in HSV-1 that has driven the significant advances in developing

methodstoidentifyCandida.b. Itisnotanincreaseinoralcancerthathasdriventhesignificantadvancesindeveloping

methodstoidentifyCandida.c. Correct.Increasinguseof immunosuppressivetherapyhasenhancedtheprevalenceof

candidoses.d. The increased use of dental implants is not associated with higher incidence of

candidosis.

REF:Chaptersummary,p.179

32. ANS:aa. Correct.Useofsteroidinhalersisapredisposingfactorfororalcandidosis.b. Receiptofantiviraltherapyisnotapredisposingfactorfororalcandidosis.c. Theuseofantimicrobialmouthrinsesisnotapredisposingfactorfororalcandidosis.d. Herpessimplexvirusinfectionisnotapredisposingfactorfororalcandidosis.


33. ANS:aa. Correct. Indenturewearerswhohavechronicerythematouscandidosis, improvement

ofdenturehygieneisparamounttomanagementofthiscondition.b. Reducing carbohydrate intake is not necessarily paramount to management of this

condition.c. Antibiotictherapyindenturewearerswhohavechronicerythematouscandidosisisnot

necessarilyparamounttomanagementofthiscondition.d. Reducing alcohol consumption is not necessarily paramount to management of this

condition.


34. ANS:ca. Defensinshaveanti-candidalactivitybutarenotnecessarilyspecifictothemouth.b. Mucinshaveanti-candidalactivitybutarenotnecessarilyspecifictothemouth.c. Correct. Histatins are antimicrobial peptides largely specific to the mouth and have

anti-candidalactivity.d. Transferrinshaveanti-candidalactivitybutarenotnecessarilyspecifictothemouth.

REF:Hostresponsetooralcandidosis,p.172

143

C H A P T E R 10

Orofacial Viral Infections

Multiple Choice1. Whichofthefollowingistheestimatedpercentageofadultswhoharbourvirusesthathave

beenacquiredasaresultofpriorinfection?a. 60%.b. 10%.c. 45%.d. 90%.

2. Whichofthefollowingistheprincipalbasisforthedevelopmentoftheantiviraldrugsthatarecurrentlyavailable?a. Virusassembly.b. Viralreplication.c. Proteinsynthesis.d. Adsorption.

3. Whichofthefollowinghascontributedtothedifficultyindesigningeffectiveantiviraldrugtherapies?a. Viralreplication.b. Intracellularnatureofinfection.c. Proteinsynthesis.d. Cellmembranestructure.

4. Whatistheapproximatesizeofviruses?a. 5–50nm.b. 100–300nm.c. 400–600nm.d. 650–850nm.

5. Whichofthefollowingisaweaknessofelectronmicroscopyforuseasadiagnostictechnique?a. Highspecificity.b. Lowsensitivity.c. Lowspecificity.d. Highsensitivity.

6. Thedevelopmentofwhichofthefollowingwasamilestoneinantiviraltherapy,representingthefirsttruespecificantiviralagent?a. Atazanavir.b. Lopinavar.c. Aciclovir.d. Nexavir.

144 10—OrOfacIal VIral InfectIOns

7. Aciclovir is a nucleoside analogue drug that has activity against which of the followingmembersoftheherpesgroupofviruses?a. Epstein–Barrvirus.b. Cytomegalovirus.c. Kaposi’ssarcomaherpesvirus.d. Herpessimplextype-1(HSV-1).

8. Whichofthefollowingistheprimarymechanismofactionforaciclovir?a. Virusassembly.b. InhibitionofviralDNAsynthesis.c. Blockingviralreplication.d. Destructionoftheviralcellmembrane.

9. WhichofthefollowingistheGreekmeaningofthenameherpes?a. Slow.b. Tocreep.c. Prolong.d. Rapid.

10. Which of the following represents the prevalence/incidence of a primary infection withHSV-1inthepopulationintheWesternworld?a. Never.b. Universally.c. Infrequently.d. Often.

11. WhichofthefollowingistheacronymforKaposi’ssarcomaherpesvirus?a. HSV-1.b. HCMV.c. EBV.d. HHV-8.

12. WhichistheappropriateagentofchoiceforapatientwhopresentswithherpeticgingivitisdiagnosticforHSV-1?a. Amoxicillin.b. Aciclovir.c. Chlorhexidine.d. Polymixin.

13. Regardlessoftheuseofanantiviralagent,HSV-1isnoteliminatedfromthebodyfollowingresolutionoftheacutesymptomsandthevirusremainswithinthetissuesinwhichofthefollowingstates?a. Prodromal.b. Resistant.c. Latent.d. Active.

10—OrOfacIal VIral InfectIOns 145

14. WhatistheapproximateincidenceofrecurrentepisodesofHSV-1?a. 25%.b. 100%.c. 40%.d. 75%.

15. ReactivationofHSV-1characteristicallyproducesherpes labialis,knownmorecommonlyaswhichofthefollowing?a. Lipsore.b. Coldsore.c. Mucosallesion.d. Oralblister.

16. Traditionally,ithasbeenthoughtthatreactivatedHSV-1migratedtotheperipheraltissuesofthelipsorfacefromwhichofthefollowing?a. Hypoglossalnerve.b. Trigeminalganglion.c. Zygomaticnerve.d. Buccalnerve.

17. The prodromal symptom of herpes labialis (a tingle or burning sensation) originates onwhichofthefollowing?a. Buccalmucosa.b. Gingivalmargin.c. Attachedgingiva.d. Vermillionborderoflips.

18. Approximatelywhatpercentageofherpeslabialisepisodeshavenoprodromalstageandthelesioninitiatesasvesicles?a. 10%.b. 25%.c. 50%.d. 90%.

19. Whichofthefollowingissocharacteristicofherpeslabialisthatdiagnosisisbasedonthissymptomalone?a. Gingivostomatitis.b. Vesiculobullouslesions.c. Vesiclesthatruptureandcrustover.d. Pyrexia.

20. Which of the following predisposes susceptible individuals to an episode of herpeslabialis?a. Poornutrition.b. Toothbrushabrasion.c. Pre-existinggingivitis.d. Sunlight.


21. Individualswithsevereorfrequentrecurrencesofherpeslabialiscanbenefitfromthepro-phylacticuseofwhichofthefollowing?a. Antimicrobialrinse.b. Stannousfluoriderinse.c. Ganciclovir.d. Systemicaciclovir.

22. ItisalsorecognisedthatlatentHSV-1isasymptomaticandisshedatleastonceamonthinthesalivainwhatpercentageofthepopulation?a. 25%.b. 10%.c. 70%.d. 50%.

23. Varicellazostervirus(VZV)primaryinfectionoccursmostfrequentlyinchildhoodcausingwhichofthefollowing?a. Whoopingcough.b. Chickenpox.c. Respiratoryinfection.d. Pinkeye.

24. ReactivationoflatentVZVinsensorynervegangliaproducestheclinicalconditionofherpeszoster,whichismorecommonlydescribedaswhichofthefollowing?a. Shingles.b. Coldsores.c. Hand,footandmouthdisease.d. Glandularfever.

25. Epstein–Barrvirus(EBV)hasbeenassociatedwithanumberofinfectionsthataffecttheorofacialregionincludingwhichofthefollowing?a. Oropharyngealcandidiasis.b. Infectiousmononucleosis.c. Parotitis.d. Sialadenitis.

26. Theonsetof apainful throat and submandibular lymphadenopathy, accompaniedbyfinepetechial haemorrhages in the hard and soft palate, is evident in which of the followingconditions?a. Acuteupperrespiratoryinfection.b. Meningitis.c. Infectiousmononucleosis.d. Cytomegalovirusinfection.

27. Characteristically,whichofthefollowingpresentsasacorrugatedwhitelesiononthelateralborderofthetongue?a. Aphthousulcer.b. Hairyleukoplakia.c. Medianrhomboidglossitis.d. Lichenplanus.


28. AnaggressivetumourofthejawassociatedwiththeEpstein-Barrvirus(EBV)oncogenicvirusiswhichofthefollowing?a. Hodgkinslymphoma.b. Burkitt’slymphoma.c. Basalcellcarcinoma.d. Non-Hodgkinslymphoma.

29. Human herpes virus 8 (HHV-8) is believed to be the aetiological agent of which of thefollowing?a. Humanpapillomavirus.b. Kaposi’ssarcoma.c. Humanimmunodeficiencyvirus.d. Severeacuterespiratorysyndromevirus(SARS).

30. Thediagnosisofhand,footandmouthdiseaseisusuallymadeonthebasisofwhichofthefollowing?a. Cultures.b. Characteristicclinicalsigns.c. Electronmicroscopy.d. Serologicaltesting.

31. Herpanginaiscausedbywhichofthefollowing?a. Humanherpesvirus8(HHV-8).b. Humanherpesvirus7(HHV-7).c. EBV.d. Coxsackievirussubspecies.

32. Treatmentofherpanginaconsistsofbedrestandtheuseofwhichofthefollowing?a. Antifungalagents.b. Antimicrobialrinses.c. Antibiotics.d. Antiviralagents.

33. Howmanyserologicaltypesofhumanpapillomavirushavebeendescribed?a. 10.b. 80.c. 50.d. 200.

Feedback1. ANS:d

a. Ithasbeenestimated that90%ofadultsharbourviruses thathavebeenacquiredasaresultofinfectionduringearlierlife.

b. Ithasbeenestimated that90%ofadultsharbourviruses thathavebeenacquiredasaresultofinfectionduringearlierlife.

c. Ithasbeenestimated that90%ofadultsharbourviruses thathavebeenacquiredasaresultofinfectionduringearlierlife.

d. Correct.Ithasbeenestimatedthat90%ofadultsharbourvirusesthathavebeenacquiredasaresultofinfectionduringearlierlife.



2. ANS:ba. Virusassemblyisnottheprincipalbasisforthedevelopmentoftheantiviraldrugsthat

arepresentlyavailable.b. Correct.Knowledgeofthedifferentstepsinviralreplicationhasbeentheprincipalbasis

forthedevelopmentoftheantiviraldrugsthatarepresentlyavailable.c. Proteinsynthesisisnottheprincipalbasisforthedevelopmentoftheantiviraldrugsthat

arepresentlyavailable.d. Adsorptionisnottheprincipalbasisforthedevelopmentoftheantiviraldrugsthatare

presentlyavailable.

REF:Antiviralagents,p.180

3. ANS:ba. Viral replicationhasnotnecessarilycontributed to thedifficulty indesigningeffective

antiviraldrugs.b. Correct.Theintracellularnatureofinfectionandtheabilityofvirusestoestablishlatent

formshavecontributedtothedifficultyindesigningeffectiveantiviraldrugs.c. Proteinsynthesishasnotnecessarilycontributedtothedifficultyindesigningeffective

antiviraldrugs.d. The viral cellmembranehasnotnecessarily contributed to thedifficulty indesigning

effectiveantiviraldrugs.


4. ANS:ba. Theapproximatesizeofvirusesis100–300nm.b. Correct.Theapproximatesizeofvirusesis100–300nm.c. Theapproximatesizeofvirusesis100–300nm.d. Theapproximatesizeofvirusesis100–300nm.


5. ANS:ca. Theelectronmicroscopymethodhaslowspecificity.b. Theelectronmicroscopymethodhaslowspecificity.c. Correct.Electronmicroscopycanbeusedtoprovideaprovisionalidentificationbased

onthemorphologicalappearanceofviralparticlesbutthisapproachhaslowspecificityandrequiresadditionaltests.

d. Theelectronmicroscopymethodhaslowspecificity.


6. ANS:ca. Atazanavirwasnotthefirsttruespecificantiviralagentdeveloped.b. Lopinavarwasnotthefirsttruespecificantiviralagentdeveloped.c. Correct.Thedevelopmentofaciclovirwasamilestoneinantiviraltherapy,representing

thedevelopmentofthefirsttrue,specificantiviralagent.d. Nexavirwasnotthefirsttruespecificantiviralagentdeveloped.



7. ANS:da. AciclovirisnotmostaffectiveagainstEpstein–Barrvirus.b. Aciclovirisnotmostaffectiveagainstcytomegalovirus.c. AciclovirisnotmostaffectiveagainstKaposi’ssarcomaherpesvirus.d. Correct.Aciclovirisanucleosideanaloguedrugthathasactivityagainstmembersofthe

herpesgroupofviruses,inparticularHSV-1.

REF:Antiviralagents,pp.180–181

8. ANS:ca. Virusassemblyisnottheprimarymechanismofactionforaciclovir.b. Inhibition of viral DNA synthesis is not the primary mechanism of action for

aciclovir.c. Correct.Acicloviractsbyblockingviralreplication.d. Destruction of the viral cell membrane is not the primary mechanism of action for

aciclovir.


9. ANS:ba. ThenameherpescomesfromtheGreekword‘herpein’whichdoesnotmean‘slow’.b. Correct.ThenameherpescomesfromtheGreekword‘herpein’whichmeanstocreep

(chronic,recurrent).c. The name herpes comes from the Greek word ‘herpein’ which does not mean

‘prolong’.d. ThenameherpescomesfromtheGreekword‘herpein’whichdoesnotmean‘rapid’.

REF:Herpesviruses,p.182

10. ANS:ba. PrimaryinfectionwithHSV-1occursalmostuniversallyinthepopulationintheWestern

world.b. Correct.PrimaryinfectionwithHSV-1usuallyoccursduringthefirstfewyearsoflife

andserummarkersofinfectionwiththevirusarefoundalmostuniversallyinthepopula-tionintheWesternworldby15yearsofage.

c. PrimaryinfectionwithHSV-1occursalmostuniversallyinthepopulationintheWesternworld.

d. PrimaryinfectionwithHSV-1occursalmostuniversallyinthepopulationintheWesternworld.

REF:Herpesviruses,p.182

11. ANS:da. HSV-1istheacronymforHerpessimplexvirus1.b. HCMVistheacronymforcytomegalovirus.c. EBVistheacronymforEpstein–Barrvirus.d. Correct. The acronym for Kaposi’s sarcoma herpes virus is HHV-8 (human herpes

virus8).

REF:Herpessimplextype1(HSV-1)–primaryinfection,Table10.2,pp.182–183


12. ANS:ba. Theagentofchoiceisaciclovir,notamoxicillin,forpatientswhopresentwithsignsand

symptomsofprimaryherpeticgingivitis.b. Correct.Theagentofchoiceisaciclovirforpatientswhopresentwithsignsandsymp-

tomsofprimaryherpeticgingivitis.c. Chlorhexidineisnottheagentofchoiceforpatientswhopresentwithsignsandsymp-

tomsofprimaryherpeticgingivitis.d. Theagentofchoiceisaciclovir,notpolymixin,forpatientswhopresentwithsignsand

symptomsofprimaryherpeticgingivitis.

REF:Herpessimplextype1(HSV-1)–primaryinfection,pp.182–183

13. ANS:ca. Prodromalissymptomaticoftheonsetorearlystageofadiseaseandisnottheformin

whichtheHSV-1remainsinthetissues.b. TheHSV-1thatremainsinthetissuesisnotinaresistantstate.c. Correct.Regardlessoftheuseofanantiviralagent,HSV-1isnoteliminatedfromthe

bodyfollowingresolutionoftheacutesymptomsandthevirusremainswithinthetissuesinalatentformandcanreactivate.

d. TheHSV-1thatremainsinthetissuesisnotinanactivestate.

REF:Herpessimplextype1(HSV-1)–primaryinfection,pp.182–183

14. ANS:ca. Up to40%ofHSV-1positive individuals suffer from recurrent episodesof secondary

infection.b. Up to40%ofHSV-1positive individuals suffer from recurrent episodesof secondary

infection.c. Correct. Up to 40% of HSV-1 positive individuals suffer from recurrent episodes of

secondaryinfection.d. Up to40%ofHSV-1positive individuals suffer from recurrent episodesof secondary

infection.

REF:Herpessimplextype1(HSV-1)–secondaryinfection,pp.183–184

15. ANS:ba. Lipsoreisnotthemorecommonlyknowntermforherpeslabialis.b. Correct.ReactivationofHSV-1characteristicallyproducesherpeslabialis,knownmore

commonlyasacoldsoreorfeverblister.c. Mucosallesionisnotthemorecommonlyknowntermforherpeslabialis.d. Oralblisterisnotthemorecommonlyknowntermforherpeslabialis.

REF:Herpessimplextype1(HSV-1)–secondaryinfection,pp.183–184


16. ANS:ba. Hypoglossalnerveinnervatesthemusclesofthetongue.b. Correct.Traditionally, it has been thought that reactivatedHSV-1migrates from the

trigeminalgangliontotheperipheraltissuesofthelipsorface.c. Thezygomaticnerve supplies the skinof thecheekand temporal region,not theoral

cavity.d. Buccalnerveprovidessensoryinnervationtotheskinandmucosaofthecheek.

REF:Herpessimplextype1(HSV-1)–secondaryinfection,p.184

17. ANS:da. Herpeslabialisdoesnotcharacteristicallybeginonthebuccalmucosa.b. Herpeslabialisdoesnotcharacteristicallybeginatthegingivalmargin.c. Herpeslabialisdoesnotcharacteristicallybeginattheattachedgingiva.d. Correct.Herpeslabialischaracteristicallybeginsatthevermillionborderofthelips.


18. ANS:ba. Approximately 25% of episodes have no prodromal stage and the lesion initiates as

vesicles.b. Correct.Approximately25%ofepisodeshavenoprodromalstageandthelesioninitiates

asvesicles.c. Approximately25%ofepisodeshavenoprodromalstageandthelesioninitiatesasvesicles.d. Approximately25%ofepisodeshavenoprodromalstageandthelesioninitiatesasvesicles.


19. ANS:ca. Vesicles that rupture and crust over, not gingivostomatitis, is characteristic of herpes

labialis.b. Vesiculobullouslesionsarenotcharacteristicofherpeslabialis.c. Correct.Within48hoursthevesiclesrupturetoleaveanerosion,whichsubsequently

crustsoverandeventuallyheals,within7–10days.d. Pyrexiaisnotcharacteristicofherpeslabialis.


20. ANS:da. Poornutritiondoesnotnecessarilypredisposeanindividualtothedevelopmentofherpes

labialis.b. Toothbrush abrasion does not predispose an individual to the development of herpes

labialis.c. Pre-existinggingivitisdoesnotnecessarilypredisposeanindividualtothedevelopment

ofherpeslabialis.d. Correct.Factorsthatpredisposeasusceptible individualtothedevelopmentofherpes

labialisincludesunlight,trauma,stress,fever,menstruation,andimmunosuppression.



21. ANS:da. Anantimicrobialrinsewouldnotbeeffectivetouseprophylacticallytopreventindividu-

alswithsevereorfrequentrecurrencesfromexperiencingadditionaloutbreaks.b. Astannousfluoriderinsewouldnotbeeffectivetouseprophylacticallytopreventindi-

vidualswithsevereorfrequentrecurrencesfromexperiencingadditionaloutbreaks.c. Ganciclovirandfoscarnetaretwootherantiviralagentsthatareusedinspecialistunits

fortreatmentofinfectionsduetocytomegalovirus.d. Correct.Individualswithsevereorfrequentrecurrencescanbenefitfromtheprophylactic

useofsystemicaciclovir.


22. ANS:ca. LatentHSV-1isasymptomaticandshedsperiodicallyinthesalivaofupto70%ofthe

populationatleastonceamonth.b. LatentHSV-1isasymptomaticandshedsperiodicallyinthesalivaofupto70%ofthe

populationatleastonceamonth.c. Correct.LatentHSV-1 is asymptomatic and shedsperiodically in the salivaofup to

70%ofthepopulationatleastonceamonth.d. LatentHSV-1isasymptomaticandshedsperiodicallyinthesalivaofupto70%ofthe

populationatleastonceamonth.


23. ANS:ba. Whoopingcoughisnotcausedbythevaricellazostervirus(VZV).b. Correct. VZV primary infection occurs most frequently in childhood, causing

chickenpox.c. RespiratoryinfectionisnotcausedbytheVZV.d. PinkeyeisnotcausedbytheVZV.

REF:Varicellazostervirus(VZV)–primaryinfection,p.185

24. ANS:aa. Correct.ReactivationoflatentVZVinsensorynervegangliaproducestheclinicalcondi-

tionofherpeszoster,whichismorecommonlydescribedasshingles.b. ColdsoresarecausedbyHSV-1,notVZV.c. Hand,footandmouthdiseaseiscausedbyCoxsackieviruses.d. GlandularfeveriscausedbyEBV.

REF:Varicellazostervirus(VZV)–secondaryinfection,p.185

25. ANS:ba. OropharyngealcandidiasisisnotassociatedwiththeEBV.b. Correct.EBVhasbeenassociatedwithanumberofinfectionsthataffecttheorofacial

regionincludinginfectiousmononucleosis.c. ParotitisisnotassociatedwiththeEBV.d. SialadenitisisnotassociatedwiththeEBV.

REF:Epstein–Barrvirus,p.186


26. ANS:ca. Acuteupperrespiratoryinfectiondoesnotpresentwithfine,petechialhaemorrhagesin

thehardandsoftpalate.b. Meningitisdoesnotpresentwithfine,petechialhaemorrhagesinthehardandsoftpalate.c. Correct.Theonsetofapainfulthroatandsubmandibularlymphadenopathyaccompa-

niedbyfinepetechialhaemorrhages in thehardand softpalate is associatedwith theonsetofinfectiousmononucleosis.

d. Cytomegalovirusinfectiondoesnotpresentwithfinepetechialhaemorrhagesinthehardandsoftpalate.

REF:Infectiousmononucleosis,p.186

27. ANS:ba. Aphthousulcersdonotpresentascorrugatedwhitelesionsonthelateralborderofthe

tongue,butasdiscreteroundlesionswithayellowcentretypicallyonoralmucosa.b. Correct.Characteristically,hairyleukoplakiapresentsasacorrugatedwhitelesiononthe

lateralborderof thetongue,althoughithasalsobeendescribedonthedorsumofthetongueandthebuccalmucosa.

c. Median rhomboidglossitis is seenasa symmetrical shapedarea in themidlineof thedorsumofthetongue.

d. Lichenplanusdoesnotpresentasacorrugatedwhitelesiononthelateralborderofthetongue,althoughithasalsobeendescribedonthedorsumofthetongueandthebuccalmucosa.

REF:Hairyleukoplakia,p.186

28. ANS:ba. Hodgkinslymphomaisnotatumourofthejaw.b. Correct. Burkitt’s lymphoma is an aggressive tumour of the jaws seen in areas where

malariaisprevalent,especiallyinChinaandSoutheastAsia.c. Basalcellcarcinomaisnotatumourofthejaw.d. Non-Hodgkinslymphomaisnotatumourofthejaw.

REF:Burkitt’slymphomaandnasopharyngealcarcinoma,p.187

29. ANS:ba. HHV-8isnottheaetiologicalagentofhumanpapillomavirus.b. Correct.HHV-8hasbeenencounteredinallformsofKaposi’ssarcomaandisbelieved

tobetheaetiologicalagentofthiscondition.c. HHV-8isnottheaetiologicalagentofhumanimmunodeficiencyvirus.d. HHV-8isnottheaetiologicalagentofSARS.

REF:Humanherpesvirus8(HHV-8),p.187


30. ANS:ba. Thediagnosisofhand,footandmouthdiseaseisnotmadebyculture.b. Correct.Thediagnosisofhand,footandmouthdiseaseisusuallymadeonthebasisof

thecharacteristicclinicalsigns.Lesionsinvolvemacularandvesiculareruptionsonthehands,feetandmucosaofthepharynx,softpalate,buccalsulcusortongue.

c. Hand,footandmouthdiseaseisnotdiagnosedthroughelectronmicroscopy.d. Hand,footandmouthdiseaseisnotdiagnosedthroughserologicaltesting.

REF:Hand,footandmouthdisease,p.187

31. ANS:da. HHV-8isnotthecauseofherpangina.b. HHV-7isnotthecauseofherpangina.c. EBVisnotthecauseofherpangina.d. Correct.Herpanginaisaconditionthatoccurspredominantlyinchildren,andpresents

assuddenonsetoffeverandsorethroatwithsubsequentdevelopmentofpapular,vesicularlesionsontheoralmucosaandpharyngealmucosaand iscausedbyaCoxsackievirussubspecies.

REF:Herpangina,p.187

32. ANS:ba. Antifungalagentsarenotthetreatmentofchoiceforherpangina.b. Correct.Treatment consists of bed rest and the use of an antimicrobial rinse such as

chlorhexidine.c. Antibioticsarenotthetreatmentofchoiceforherpangina.d. Anantiviralagentisnotthetreatmentofchoiceforherpangina.

REF:Herpangina,p.187

33. ANS:ba. Morethan80serologicaltypesofhumanpapillomavirushavebeendescribed.b. Correct.Morethan80serologicaltypesofhumanpapillomavirushavebeendescribed.c. Morethan80serologicaltypesofhumanpapillomavirushavebeendescribed.d. Morethan80serologicaltypesofhumanpapillomavirushavebeendescribed.

REF:Humanpapillomavirus,p.188

155

C H A P T E R 11

Oral Implications of Infection in Compromised Patients

Multiple Choice1. Moleculartechniqueshaveidentifiedwhichofthefollowingmicroorganismsfromcasesof

osteoradionecrosis?a. Staphylococci,includingmethicillinresistantStaphylococcus aureus(MRSA).b. OralGramnegativeanaerobes,includingPorphyromonasandPrevotellaspp.c. Streptococci,includingS. intermedius.d. Actinomyces,includingA. israelii.

2. Thenumberofimmunocompromisedindividualsisincreasingrapidly,mostlybecauseoftheacquiredimmunodeficiencysyndrome(AIDS)pandemic,butalsobecauseofwhichofthefollowing?a. Prematurebirths.b. Alcoholsyndrome.c. Ageingpopulation.d. Interventiontherapy(drugswhichdeliberatelymodifytheimmunesystem).

3. Whichofthefollowingmicroorganismsareassociatedwithpost-irradiationmucositis?a. Candida albicans.b. Non-oralGramnegativefacultativebacteria.c. OralGramnegativeanaerobes.d. Staphylococci.

4. InpatientssufferingfromlossoforalmusculatureduetoParkinson’sdiseaseorfollowingastroke,whatofthefollowingchangeshasbeenobservedintheoralmicroflora?a. Anincreaseintheprevalenceofyeasts.b. AnincreaseintheprevalenceofenterobacteriaandAcinetobacter.c. Anincreaseintheprevalenceofstaphylococci,includingMRSA.d. Anincreaseintheprevalenceofmycoplasmas.

5. Whichofthefollowingtestsassessestheextentofsusceptibilitytoinfectionofanimmu-nocompromisedpatient?a. Proportionofwhitebloodcells.b. High-densitylipoprotein(HDL).c. Liverbiopsy.d. Alanineaminotransferase(ALT).

156 11—Oral ImPlICatIOns Of InfeCtIOn In COmPrOmIsed PatIents

6. Whichofthefollowingcancauseanorofacialinfectioninamedicallycompromisedpatient?a. AIDS.b. Endocrinedisorder.c. Cardiacdisorder.d. Arthriticdisorder.

7. Of the following, which orofacial infection might a patient with a neurological disorderexperience?a. Mucositisfollowingradiotherapy.b. Angularcheilitis.c. Gingivalhyperplasia.d. Oralfungalinfection.

8. Anopportunisticorofacialinfectionmaybeindicativeofwhichofthefollowing?a. Anunderlyingbacterialovergrowth.b. Asmokinghabit.c. Initialfeatureofsystemicdisease.d. Ahormonaldisorder.

9. Radiationaffectsboneinwhichofthefollowingways?a. Hypercellularity.b. Increasesriskforfracture(osteoporodic).c. Hypervascularity.d. Tissuehypoxia.

10. Cancerintheoralregionistreatedusuallybywhichofthefollowing?a. Surgery.b. Radiotherapy.c. Chemotherapy.d. Acombinationofallthree.

11. Necrotisingfasciitisofthecervicalregionoftheneckisassociatedwithwhichofthefol-lowingmicroorganisms?a. Flesh-eatingstreptococci(e.g.,Streptococcus pyogenes).b. Spirochaetesandfusobacteria(fuso-spirochaetalcomplex).c. Anginosusgroupofstreptococciandobligateanaerobes.d. Non-oralGramnegativebacilli,e.g.,AcinetobacterandKlebsiellaspp.

12. Asimpleoperationonirradiatedtissues,suchasatoothextraction,canresultinwhichofthefollowing?a. Scartissueformation.b. Spontaneousdeathofthesurroundingbone(necrosis).c. Verysensitivetissue.d. Contactdermatitis.

13. Deathofthebonefollowingirradiationcanbeprogressiveandiscalledwhichofthefollowing?a. Avascularnecrosis.b. Osteonecrosis.c. Osteoradionecrosis.d. Osteoporosis.

11—Oral ImPlICatIOns Of InfeCtIOn In COmPrOmIsed PatIents 157

14. Osteoradionecrosishasbeenassociatedwithoralulcerationcausedbyallof the followingexceptwhichofthefollowing?a. Ill-fittingdentures.b. Scalingoftheteeth.c. Restorationofocclusaltoothsurfaces.d. Facialbonefractures.

15. Xerostomiaisassociatedwithwhichofthefollowingchangestotheoralmicroflora?a. Anincreaseinstaphylococci.b. Anincreaseinenterobacteria.c. Andincreaseinmutansstreptococciandlactobacilli.d. Adecreaseinyeasts.

16. Withcarefulcollimation,shieldingofsurroundingtissues,andfractionation,theincidenceofosteoradionecrosishasbeenreducedtowhichofthefollowing?a. 2–5%.b. 10–15%.c. 15–20%.d. 25–30%.

17. Osteoradionecrosisislikelytoariseduetowhichofthefollowing?a. Surgery.b. Radiation,traumaandinfection.c. Antimicrobialside-effects.d. Inadequateoralhygienepost-radiationtherapy.

18. Although osteoradionecrosis is difficult to treat, which of the following is used as atreatment?a. Salinerinses.b. Sodiumfluoridetrays.c. Hormonetherapy.d. Antibacterialagents.

19. Thenon-specificinflammationoftheoralmucosaresultingfromirradiationiscalledwhichofthefollowing?a. Aphthousstomatitis.b. Mucositis.c. Gingivostomatitis.d. Candidiasis.

20. Irradiation mucositis can be largely alleviated by selective decontamination of the oralcavity prior to and during irradiation therapy by the topical application of which of thefollowing?a. Metronidazole.b. Chlorhexidineandantifungalagents.c. Acombinationofpolymixinandtobramycin,plusantifungalagents.d. Amoxicillin.


21. Whichofthefollowingistherationalefortheuseofbisphosphonatesinthetreatmentofosteoporosis?a. Boneisdestroyedduetocancer.b. Bonebecomesbrittleduetoradiologicaltreatment.c. Calciumisgraduallylostfrombone.d. Boneiscompromisedduetolong-termantibiotictherapy.

22. Whichofthefollowingconditionscanbeexacerbatedbybisphosphonateuse?a. Incidenceofmucositis.b. Fungalovergrowth.c. Failureofbonetohealafterextractions/osteonecrosis.d. Incidenceofhumanpapillomavirus(HPV).

23. The main viral coat protein used by human immunodeficiency virus (HIV) to attach toCD4+lymphocytesiswhichofthefollowing?a. gp80.b. gp100.c. gp120.d. gp180.

24. Staphylococcusspp.arenotalwaysconsideredanormalmemberoftheresidentoralmicroflora,buttheycanbeisolatedfromthemouthinwhichofthefollowingpatientpopulations?a. Paediatric.b. Debilitated.c. Juvenile.d. Healthy.

25. Theanti-HIVdrugtreatmentisknownbywhichofthefollowingacronyms?a. AR-HIV.b. T-AIDS.c. HEART.d. HAART.

26. Bisphosphonatesarepyrophosphateanalogues thatcanpreventosteoporosisby inhibitingwhichofthefollowing?a. Leukocytes.b. Osteoclastactivity.c. Insulinproduction.d. Pancreaticenzymes.

27. Pyostomatitisvegetansisassociatedwiththepresenceofwhichofthefollowing?a. Hypertension.b. Encephalopathy.c. Crohn’sdisease.d. Diabetes.

28. Cancrumoris(noma,gangrenousstomatitis)iswhichofthefollowing?a. Severeformofgingivostomatitis.b. Severeformoflichenplanus.c. Severeformofmucositis.d. Severeformofnecrotisingperiodontaldisease.


29. Cancrumorisischaracteristicallyseeninwhichofthefollowingpatientpopulation?a. Overage50withahistoryofinfectiveendocarditisandperiodontitis.b. Lessthan10yearsold,malnourishedandhistoryofrecentviralinfection.c. Middleaged,historyofdiabetesandhypertension.d. Overage75withahistoryofimmunedysfunctionanddiabetes.

30. Whichofthefollowingcanoccurfollowingastroke(andisalsoseeninconditionssuchasParkinson’sdisease)?a. Severeformofgingivostomatitis.b. Lossofcontroloforalmusculature.c. Necrotisingfasciitis.d. Xerostomia.

31. Aserious,life-threatening,rapidlyprogressiveinfectionsubsequenttoanacutedentoalveolarabscessseeninthecervicalregionoftheneckofimmunocompromisedindividualsiswhichofthefollowing?a. Severegingivostomatitis.b. Necrotisingfasciitis.c. Severeoralthrush.d. Severeorallichenplanus.

32. Whichofthefollowingliterallymeans‘drymouth’?a. Alveolarosteitis.b. Xerostomia.c. Lichenplanus.d. Aphthousstomatitis.

33. Xerostomiapredisposesthedevelopmentofwhichofthefollowing?a. Herpessimplextype1(HSV-1).b. Mucositis.c. Lichenplanus.d. Necrotisingfasciitis.

34. Xerostomiahasseveralcausesincludingwhichofthefollowing?a. Coxsackievirusinfection.b. Antimicrobialrinses.c. Pharmaceuticalandover-the-counter(OTC)drugs.d. ExcessofvitaminD.

35. Theuseofanantirejectionagentcancausewhichofthefollowingfibrousgingivalenlarge-mentstooccur?a. Stomatitis.b. Aphthousstomatitis.c. Gingivalhyperplasia.d. Periodontitis.


36. Theconnectionbetweenapost-strokepatient’sinabilitytoswallowproperlyandpneumoniaiswhichofthefollowing?a. Mucositis.b. Aspiratedoralmicroorganisms.c. Aphthousulcers.d. Oralthrush.

37. Whichofthefollowingenzymesisusedtoconvertdouble-strandedRNAtocomplementaryDNAinHIV?a. DNAgyrase.b. Ribonuclease.c. Reversetranscriptase.d. Deoxyribonuclease.

38. Transmissible spongiformencephalopathies (TSEs) are causedbywhichof the followinginfectiousagents?a. Virion.b. Prion.c. Unculturablebacteria.d. HBsAg.

39. ThehumanimmunodeficiencyvirusinfectspredominantlyCD4+lymphocytesbutcanalsoinfectwhichofthefollowing?a. Macrophages.b. Neutrophils.c. Monocytes.d. Mastcells.

40. The agents responsible forTSEs are difficult to treat. Which of the following is not anattributeassociatedwiththeseagents?a. Bindfirmlytostainlesssteel.b. Possessantibioticresistancetomultipledrugs.c. Resistanttoautoclaving.d. Resistanttostrongdisinfectants.

41. WhatistheapproximaterateoftransmissionofHIVifinfectedbloodistransmittedtoanuninfectedperson?a. <5%.b. 10%.c. 25%.d. 50%.

42. AIDS results from a depletion of CD4+ lymphocytes also known as which of thefollowing?a. B-cells.b. T-helpercells.c. Macrophages.d. KillerT-cells.


43. AgentsthatcauseTSEsarecomposedonwhichofthefollowing?a. dsDNA.b. dsRNA.c. ssRNA.d. Protein.

44. WhichofthefollowinglesionsisstronglyassociatedwithHIV?a. Necrotisingstomatitis.b. Thrombocytopenicpurpura.c. Candidosis.d. Hand,footandmouthdisease.

45. WhichofthefollowinglesionsisonlymoderatelyassociatedwithHIV?a. Hairyleukoplakia.b. Varicellazostervirus.c. Non-Hodgkinslymphoma.d. Kaposi’ssarcoma.

46. HIVcaneasilypenetratetheblood–brainbarrierresultinginmentaldeteriorationthatcanbemisdiagnosedaswhichofthefollowing?a. Meningitis.b. Depression.c. Generalizedanxiety.d. Dementia.

47. Intheearlystagesofinfection,HIVreleasesaprotein,p24,whichcanbedetectedsometimesasearlyaswithinwhichofthefollowing?a. Oneweektoonemonth.b. Onetotwomonths.c. Threemonths.d. Sixmonths.

48. HepatitisBcanbefoundinthebloodofinfectedpatients.ThedetectionofwhichofthefollowingcanbeusedtodiagnosehepatitisB?a. HBsAg.b. PRP.c. GenomicviralDNA.d. GenomicviralRNA.

49. OneofthemostsignificantadvancesinthetreatmentofHIVistheuseofwhichofthefollowing?a. Activeantiretroviraltherapy.b. Azothymidine(AZT).c. Antiviraltherapy.d. Antibacterialagents.

50. Thecurrentvaccinefortuberculosis(TB)isknownaswhichofthefollowing?a. MDR-TB.b. MMR.c. BCG.d. XDR-TB.


51. Syphiliscanpresentwithorallesions.Whichofthefollowingisthecausativebacterium?a. Treponema denticola.b. Treponema socranskii.c. Treponema pallidum.d. Treponema putidum.

Feedback1. ANS:b

a. Staphylococcihavenotbeendetected.b. Correct.Oralanaerobeshavebeendetected.c. Streptococcihavenotbeendetected.d. Actinomycesspp.havenotbeendetected.

REF:Osteoradionecrosis,p.191

2. ANS:da. The number of immunocompromised individuals is increasing rapidly because of the

AIDSpandemicandinterventiontherapy,notprematurebirths.b. The number of immunocompromised individuals is increasing rapidly because of the

AIDSpandemicandinterventiontherapy,notalcoholsyndrome.c. The number of immunocompromised individuals is increasing rapidly because of the

AIDSpandemicandinterventiontherapy,notanageingpopulation.d. Correct.Thenumberofimmunocompromisedindividualsisincreasingrapidly,mostly

becauseoftheAIDSpandemic,butalsobecauseofinterventiontherapy(drugswhichdeliberatelymodifytheimmunesystem).


3. ANS:ba. Yeastsarenotassociatedwiththisformofmucositis.b. Correct. Gram negative facultatively anaerobic bacteria such as pseudomonads and

Klebsiellaspeciesareassociatedwithpost-irradiationmucositis.c. OralGramnegativeanaerobesarenotassociatedwithmucositis.d. Staphylococci are associated with ‘staphylococcal mucositis’ but not post-irradiation

mucosistis.

REF:Post-irradiationmucositis,pp.191–192

4. ANS:ba. ThemicroflorainthesepatientgroupsbecomespredominantlyGramnegative.b. Correct.ThemicroflorainthesepatientgroupsbecomespredominantlyGramnegative

withEnterobacterspp.andAcinetobacterspp.predominating.c. ThemicroflorainthesepatientgroupsbecomespredominantlyGramnegative.d. ThemicroflorainthesepatientgroupsbecomespredominantlyGramnegative.

REF:StrokeandParkinson’sdisease,p.193


5. ANS:aa. Correct.Measuringtheproportionofwhitebloodcellsandtheirfunctionordegreeof

abnormality.b. A HDL measurement would not be relevant to assessing the function of a patient’s

immunesystem.c. A liver biopsy would not be relevant to assessing the function of a patient’s immune

system.d. The ALT measurement would not be relevant to assessing the function of a patient’s

immunesystem.


6. ANS:ba. AIDSwouldrepresentanimmune-compromisedratherthanamedicallycompromised

patient.b. Correct.Endocrinedisordersareonetypeofdisorderthatmayleadamedicallycom-

promisedpatienttohaveanorofacialinfection.c. Cardiacdisorderswouldpredisposeamedicallycompromisedpatienttohaveanorofacial

infection.d. Arthriticdisorderswouldpredisposeamedicallycompromisedpatienttohaveanoro-

facialinfection.

REF:Introduction,Table11.1,p.191

7. ANS:ca. Patientswithneoplasticdiseasewhoundergoradiotherapyoftendeveloporalmucositis.b. Angularcheilitisisoftenassociatedwithhaematinicdeficienciessuchasanaemia.c. Correct. Gingival hyperplasia is often associated with the neurological disorder of

epilepsy.d. Anoralfungalinfectionisassociatedwithrespiratorydisorderssuchasasthma.

REF:Introduction,Table11.1,p.191

8. ANS:ca. An orofacial infection is not likely to be the initial feature of an underlying bacterial

overgrowth.b. Therecanbemanyoralmanifestationsofchronicsmokingbuttheyarenotnecessarily

theinitialpresentingfeatureofsystemicdisease.c. Correct.The status of the teeth and oral soft tissues is often a reflection of systemic

health.Thus, opportunistic orofacial infection may be the presenting initial feature ofsystemicdisease.

d. Anorofacialinfectionisnotlikelytobetheinitialsignofahormonaldisorder.

REF:Introduction,pp.190–191


9. ANS:da. Radiationcauseshypocellularity.b. Increasedriskforfracturebecauseofosteoporodictissueisnotoneofthethreewaysthat

radiotherapydestroyssurroundingtissue.c. Radiationcauseshypovascularity.d. Correct. Radiotherapy destroys the rapidly dividing cancer cells, but it also destroys

surroundingbone.Thisboneishighlysusceptibletosecondaryradiationasitabsorbsagreatdealofenergy.Radiationcauseshypocellularity,hypocellularityandtissuehypoxia.


10. ANS:da. Cancerintheoralregionistreatedusuallybysurgery,radiotherapy,chemotherapyora

combinationofallthree.b. Cancerintheoralregionistreatedusuallybysurgery,radiotherapy,chemotherapyora

combinationofallthree.c. Cancerintheoralregionistreatedusuallybysurgery,radiotherapy,chemotherapyora

combinationofallthree.d. Correct.Cancer in theoral region is treatedusuallyby surgery, radiotherapy, chemo-

therapyoracombinationofallthree.


11. ANS:ca. S. pyogenesisassociatedwithnecotisingfasciitisofsitesotherthancervicalregionsofthe

neck;thisisduetobacteriaofdentalorigin.b. Necrotisingfasciitisofthecervicalregionsoftheneckisduetobacteriaofdentalorigin.c. Correct.Necotisingfasciitisofthecervicalregionsoftheneckisduetobacteriaofdental

originincludingmembersoftheanginosusgroupofstreptococciofteninassociationwithobligateoralanaerobessuchasPrevotellaspp.

d. Necrotisingfasciitisofthecervicalregionsoftheneckisduetobacteriaofdentalorigin.

REF:Necrotisingfasciitis,p.193

12. ANS:ba. Scartissuecanbetheresultofasurgicalprocedurebutnotjustpost-irradiationtherapy.b. Correct. A simple operation on tissues which have been irradiated, such as a tooth

extraction,canresultinspontaneousdeathofthesurroundingbone(necrosis).c. Verysensitivetissuemayoccurpost-surgicallybutnotjustpost-irradiationtherapy.d. Contactdermatitisisnotacommontissuereactionpost-surgicallyonirradiatedareas.



13. ANS:ca. Avascularnecrosisisthedeathofbonetissueduetoalackofbloodsupply.b. Osteonecrosismeansdeathofbonewhichcanoccurfromlossofbloodsupply.c. Correct. Death of the bone after irradiation can be progressive and is called

osteoradionecrosis.d. Osteoporosisisamedicalconditioninwhichthebonesbecomebrittleandfragilefrom

lossoftissue,butnotduetoirradiationtherapy.


14. ANS:ca. Deathof theboneafter irradiationcanbeprogressiveand is calledosteoradionecrosis

andhasbeenassociatedwithoralulcerationcausedbyill-fittingdentures,scalingoftheteeth,facialbonefracturesandrootcanaltherapy.

b. Deathof theboneafter irradiationcanbeprogressiveand is calledosteoradionecrosisandhasbeenassociatedwithoralulcerationcausedbyill-fittingdentures,scalingoftheteeth,facialbonefracturesandrootcanaltherapy.

c. Correct.Therestorationofocclusaltoothsurfacesisnotrelatedinanywaytodeathofboneafterradiationtherapy.

d. Deathof theboneafter irradiationcanbeprogressiveand is calledosteoradionecrosisandhasbeenassociatedwithoralulcerationcausedbyill-fittingdentures,scalingoftheteeth,facialbonefracturesandrootcanaltherapy.


15. ANS:ca. Xerostomiaisassociatedwithanincreaseinproportionsofcariogenicbacteria.b. Xerostomiaisassociatedwithanincreaseinproportionsofcariogenicbacteria.c. Correct. Xerostomia is associated with an increase in proportions of cariogenic

bacteria.d. Xerostomiacanbeassociatedwithanincreaseinyeastsinthemouth.

REF:Xerostomia,p.194

16. ANS:aa. Correct.With careful collimation, shieldingof surrounding tissues, and fractionation,

theincidenceofosteoradionecrosishasbeenreducedto2–5%.b. With careful collimation, shieldingof surrounding tissues, and fractionation, the inci-

denceofosteoradionecrosishasbeenreducedto2–5%.c. With careful collimation, shieldingof surrounding tissues, and fractionation, the inci-

denceofosteoradionecrosishasbeenreducedto2–5%.d. With careful collimation, shieldingof surrounding tissues, and fractionation, the inci-

denceofosteoradionecrosishasbeenreducedto2–5%.



17. ANS:ba. Osteoradionecrosisdoesnotresultfromsurgery.b. Correct.Osteoradionecrosisislikelytoariseduetoradiation,traumaandinfection.c. Osteoradionecrosisisnotduetoside-effectsofantimicrobials.d. Osteoradionecrosisisnotduetoinadequateoralhygienepostradiationtherapy.


18. ANS:da. Salinerinsesarenotthetreatmentofchoiceforthiscondition.b. Sodiumfluoridetraysarenotthetreatmentofchoiceforthiscondition.c. Hormonetherapyisnotnecessarilythetreatmentofchoiceforthiscondition.d. Correct.Osteoradionecrosis isadifficultconditiontotreatdespitetheprovisionofan

antibacterialagentsuchasmetronidazoleorclindamycin,combinedwithsurgery.


19. ANS:ba. Aphthousstomatitisisnotaconsequenceofirradiationoftheoralregion.b. Correct.Anotherof the consequencesof irradiationof theoral region isnon-specific

inflammationoftheoralmucosa,oftencalledpost-irradiationmucositis.c. Gingivostomatitisisnotatermusedtodescribeanon-specificinflammationoftheoral

mucosaresultingfromirradiationoftheoralregion.d. Candidiasisisnotatermusedtodescribeanon-specificinflammationoftheoralmucosa

resultingfromirradiationoftheoralregion.

REF:Post-irradiationmucositis,p.191

20. ANS:ca. Metronidazoleisnotusedtoalleviateirradiationmucositis.b. Chlorhexidineisnotusedtoalleviateirradiationmucositis.c. Correct.Irradiationmucositiscanbelargelyalleviatedbyselectivedecontaminationof

the oral cavity before and during irradiation therapy by the topical application of thecombinationofpolymixinandtobramycin,plusanantifungaltopreventovergrowthbyyeasts.

d. Amoxicillinisnotusedtoalleviateirradiationmucositis.

REF:Post-irradiationmucositis,pp.191–192

21. ANS:ca. Osteoporosisisaconditioninwhichcalciumisgraduallylostfrombone.b. Osteoporosisisnotbrittleboneduetoradiation.c. Correct.Bisphosphonatesaredrugsusedinthetreatmentofosteoporosis,acondition

inwhichcalciumisgraduallylostfrombone.d. Osteoporosisisaside-effectcausedbyantibiotictherapy.

REF:Bisphosphonate-associatedosteonecrosis,p.192


22. ANS:ca. Theincidenceofmucositisisnotexacerbatedbybisphosphonateuse.b. Fungalovergrowthcanbeexacerbatedbybisphosphonateuse.c. Correct.Somepatientswhotakebisphosphonatescansufferfromafailureofboneto

healespeciallyafterextractions(bisphosphonate-associatedosteonecrosis).d. TheincidenceofHVP-1isnotexacerbatedbybisphosphonateuse.


23. ANS:ca. Themainviralcoatglycoproteinisgp120.b. Themainviralcoatglycoproteinisgp120.c. Correct.Themainviralcoatglycoproteinisgp120.d. Themainviralcoatglycoproteinisgp120.

REF:Humanimmunodeficiencyvirus(HIV)andAIDS,Figure11.5,pp.195–196

24. ANS:ba. Staphylococcusspp.arenotfrequentlyisolatedfrompaediatricpatients.b. Correct.Recentsurveysofdatafromoralsamplesprocessedinmicrobiologylaboratories

haveshownthatStaphylococcus spp.arefrequently isolatedfromthemouthparticularlyfromdebilitatedorterminallyillpatients.

c. Staphylococcusspp.arenotfrequentlyisolatedfromjuvenilepatients.d. Staphylococcusspp.arenotfrequentlyisolatedfromhealthypatients.

REF:Staphylococcalmucositis,p.192

25. ANS:da. Theanti-HIVdrugtreatmentishighlyactiveantiretroviraltherapy(HAART).b. Theanti-HIVdrugtreatmentishighlyactiveantiretroviraltherapy(HAART).c. Theanti-HIVdrugtreatmentishighlyactiveantiretroviraltherapy(HAART).d. Correct.Theanti-HIVdrugtreatmentishighlyactiveantiretroviraltherapy(HAART).

REF:Humanimmunodeficiencyvirus(HIV)andAIDS,pp.194–197

26. ANS:ba. Bisphosphonateusedoesnotinhibitleucocyteactivity.b. Correct.Thebisphosphonatesarepyrophosphateanaloguesthatcanpreventosteoporo-

sisbyinhibitingosteoclastactivity.c. Bisphosphonateusedoesnotreducetheproductionofinsulin.d. Bisphosphonateusedoesnotaffectpancreaticenzymes.



27. ANS:ca. Hypertensionisnotassociatedwithpyostomatitisvegetans.b. Encephalopathyisnotassociatedwithpyostomatitisvegetans.c. Correct.Pyostomatitisvegetansisassociatedwiththepresenceofactiveinflammatory

boweldisease,inparticular,ulcerativecolitisorCrohn’sdisease.d. Diabetesisnotassociatedwithpyostomatitisvegetans.

REF:Pyostomatitisvegetans,p.193

28. ANS:da. Cancrumoris(noma,gangrenousstomatitis)isnotaformofseveregingivostomatitis.b. Cancrumoris(noma,gangrenousstomatitis)isnotaformofseverelichenplanus.c. Cancrumoris(noma,gangrenousstomatitis)isnotaformofseveremucositis.d. Correct. Cancrum oris (noma, gangrenous stomatitis) is a severe form of necrotising

periodontaldisease.

REF:Cancrumoris(noma,gangrenousstomatitis),p.193

29. ANS:ba. Cancrumoris (noma, gangrenous stomatitis) is characteristically seen in apatient less

than10yearsofage,malnourishedandwitharecenthistoryofviralinfection.b. Correct.Cancrumoris(noma,gangrenousstomatitis)ischaracteristicallyseeninapatient

lessthan10yearsofage,malnourishedandwitharecenthistoryofviralinfection.c. Cancrumoris (noma, gangrenous stomatitis) is characteristically seen in apatient less

than10yearsofage,malnourishedandwitharecenthistoryofviralinfection.d. Cancrumoris (noma, gangrenous stomatitis) is characteristically seen in apatient less

than10yearsofage,malnourishedandwitharecenthistoryofviralinfection.

REF:Cancrumoris(noma,gangrenousstomatitis),p.193

30. ANS:ba. The occurrence of severe gingivostomatitis is not linked to stroke nor to Parkinson’s

disease.b. Correct.Lossofcontroloforalmusculaturecanoccurfollowingastrokeandisseenin

conditionssuchasParkinson’sdisease.c. Necrotisingfasciitisisnotaconditionthatoccurssubsequenttoastrokeorinconditions

suchasParkinson’sdisease.d. Xerostomiaisnotaconditionthatoccurssubsequenttoastrokeorinconditionssuch

asParkinson’sdisease.


31. ANS:ba. Severegingivostomatitisisnotaconditionthatleadstodeath.b. Correct.Necrotisingfasciitisisaserious,rapidlyprogressiveinfectionthatcanresultin

death,particularlyinimmunocompromisedindividuals.c. Severeoralthrushisnotaconditionthatleadstodeath.d. Severeorallichenplanusisnotaconditionthatleadstodeath.

REF:Necrotisingfasciitis,p.193


32. ANS:ba. Alveolarosteitisisinflammationofthealveolarbone.b. Correct.Xerostomialiterallymeansdrymouthandcanbecausedbyavarietyofcondi-

tionsortreatments.c. Lichenplanusisadiseaseoftheskinand/ormucousmembranes.d. Aphthousstomatitisisanoralulceration.


33. ANS:ba. XerostomiadoesnotpredisposetothedevelopmentofHSV-1.b. Correct. Xerostomia predisposes to the development of mucositis and opportunistic

Candidainfectionsoftheoralmucosa.c. Xerostomiadoesnotpredisposetothedevelopmentoflichenplanus.d. Xerostomiadoesnotpredisposetothedevelopmentofnecrotisingfasciitis.


34. ANS:ca. Xerostomiaisnotcommonlycausedbyvirusinfection.b. Xerostomiaisnotcommonlycausedbyantimicrobialrinses.c. Correct.Xerostomiaisaconditionthatisquitecommonlycausedbymanypharmaceuti-

calandOTCdrugs.d. XerostomiaisnotcommonlycausedbyanexcessofvitaminD.


35. ANS:ca. Stomatitisisnotthetermforgingivalovergrowthoffibroustissue.b. Aphthousstomatitisisnotthetermforgingivalovergrowthoffibroustissue.c. Correct. Following organ transplantation, it is necessary to take immunosuppressive

agents.Theconsequencesofanantirejectionagentisgingivalenlargementduetoover-growthoffibroustissue(gingivalhyperplasia).

d. Periodontitisisnotthetermforgingivalovergrowthoffibroustissue.

REF:Gingivalhyperplasiaandimmunosuppressiveagents,p.194

36. ANS:ba. Mucositisdoesnotleadtopneumonia.b. Correct.Lossofcontroloforalmusculaturecanoccurfollowingastrokefollowedbya

change in theoralmicroflora;often thepatientcannot swallowproperlyandaspiratesthemicroflora,causingpneumonia.

c. Aphthousulcersdonotleadtopneumonia.d. Oralthrushdoesnotleadtopneumonia.



37. ANS:ca. DNAgyraseisinvolvedinsuper-coilingofdouble-strandedclosed-circularDNA.b. RibonucleasedegradesRNA.c. Correct.Reversetranscriptaseisthenameoftheenzymethatconvertsdouble-stranded

RNAtoDNAinHIV.d. DeoxyribonucleasedegradesDNA.

REF:Humanimmunodeficiencyvirus(HIV)andAIDS,p.194

38. ANS:ba. Virionsrelatetoviruses,whicharenotinvolvedinTSEs.b. Correct.PrionsaretheagentsresponsibleforTSEs.c. UnculturablebacteriadonotcauseTSEs.d. HBsAgisthehepatitisBsurfaceantigen.

REF:Transmissiblespongiformencephalopathies,pp.198–200

39. ANS:aa. Correct. The virus infects predominantly CD4+ lymphocytes but can also infect

macrophages.b. Thevirusdoesnotinfectneutrophils.c. Thevirusdoesnotinfectmonocytes.d. Thevirusdoesnotinfectmastcells.


40. ANS:ba. Prions are difficult to treat because they bind firmly to surgical instruments and are

resistanttoheatanddisinfectants.b. Correct.Prionsaredifficulttotreatbecausetheybindfirmlytosurgicalinstrumentsand

areresistanttoheatanddisinfectants.Theyarenotaffectedbyantibiotics,nordotheyhaveconventionalantibioticresistantgenes.

c. Prions are difficult to treat because they bind firmly to surgical instruments and areresistanttoheatanddisinfectants.

d. Prions are difficult to treat because they bind firmly to surgical instruments and areresistanttoheatanddisinfectants.

REF:Transmissiblespongiformencephalopathies,p.198–200

41. ANS:aa. Correct.Thetransmissionrateofthevirusisaround4%ifinfectedbloodistransmitted

toanuninfectedperson.b. The transmission rateof thevirus is around4% if infectedblood is transmitted toan

uninfectedperson.c. The transmission rateof thevirus is around4% if infectedblood is transmitted toan

uninfectedperson.d. The transmission rateof thevirus is around4% if infectedblood is transmitted toan

uninfectedperson.



42. ANS:ba. CD4+lymphocytesarealsoknownasT-helpercells.b. Correct.CD4+lymphocytesarealsoknownasT-helpercells.c. CD4+lymphocytesarealsoknownasT-helpercells.d. KillerT-cellsbelongtotheCD8+subsetoflymphocytes.


43. ANS:da. PrionscauseTSEsandarecomposedofprotein.b. PrionscauseTSEsandarecomposedofprotein.c. PrionscauseTSEsandarecomposedofprotein.d. Correct.PrionscauseTSEsandarecomposedofprotein.

REF:Transmissiblespongiformencephalopathies,p.198–200

44. ANS:ca. NecrotisingstomatitisisnotstronglyassociatedwithHIV.b. ThrombocytopenicpurpuraisnotstronglyassociatedwithHIV.c. Correct.CandidosisisstronglyassociatedwithHIV.d. Hand,footandmouthdiseaseisnotstronglyassociatedwithHIV.

REF:Humanimmunodeficiencyvirus(HIV)andAIDS;Table11.3,p.196

45. ANS:ba. HairyleukoplakiaisstronglyassociatedwithHIV.b. Correct.VaricellazostervirusismoderatelyassociatedwithHIV.c. Non-HodgkinslymphomaisstronglyassociatedwithHIV.d. Kaposi’ssarcomaisstronglyassociatedwithHIV.

REF:Humanimmunodeficiencyvirus(HIV)andAIDS;Table11.3,p.196

46. ANS:da. MeningitisisnotrelatedtoHIV’sabilitytopenetratetheblood-brainbarrier.b. DepressionisnotrelatedtoHIV’sabilitytopenetratetheblood-brainbarrier.c. GeneralizedanxietyisnotrelatedtoHIV’sabilitytopenetratetheblood-brainbarrier.d. Correct.HIVcaneasilypenetratetheblood–brainbarrierresultinginmentaldeteriora-

tionthatcanbemisdiagnosedasdementia.



47. ANS:aa. Correct.Intheearlystagesofinfection,HIVreleasesaprotein,presentinitscore,called

p24,whichcanbedetectedsometimeswithinoneweekofinfection,butalwayswithinonemonth.

b. Intheearlystagesofinfection,HIVreleasesaprotein,presentinitscore,calledp24,whichcanbedetectedsometimeswithinoneweekofinfection,butalwayswithinonemonth.

c. Intheearlystagesofinfection,HIVreleasesaprotein,presentinitscore,calledp24,whichcanbedetectedsometimeswithinoneweekofinfection,butalwayswithinonemonth.

d. In theearly stagesof infection,HIVreleasesaprotein,present in its core, calledp24,whichcanbedetectedsometimeswithinoneweekof infection,butalwayswithinonemonth.


48. ANS:aa. Correct.HepatitisBsurfaceantigen(HBsAg)canbeusedtodiagnosethevirus.b. HepatitisBsurfaceantigen(HBsAg)isusedtodiagnosethevirus.c. HepatitisBsurfaceantigen(HBsAg)isusedtodiagnosethevirus.d. HepatitisBsurfaceantigen(HBsAg)isusedtodiagnosethevirus.

REF:HepatitisB,p.200

49. ANS:aa. Correct.Oneof themost significant advances in the treatment ofHIV is theuse of

activeantiretroviraltherapy.b. WithinonemonthofthefirstuseofAZT,HIVmutantswerereportedthatwereresist-

anttothedrug.c. OneofthemostsignificantadvancesinthetreatmentofHIVistheuseofactiveanti-

retroviraltherapy.d. AntibacterialagentsarenotaneffectivetreatmentofHIV.


50. ANS:ca. MDR-TBreferstoTBcausedbyamulti-drugresistantstrain.b. MMRismumps,measlesandrubellavaccine.c. Correct.BCG(BacillusCalmette-Guerin)isthecurrentTBvaccine.d. XDR-TBreferstoTBcausedbyanextensivelyresistantstrain.

REF:Tuberculosis,p.201

51. ANS:ca. T. denticolaisanoralspirochaete.b. T. socranskiiisanoralspirochaete.c. Correct.T. pallidumisthecausativeagentofsyphilis.d. T. putidumisanoralspirochaete.

REF,Syphilis,p.202,andseealsopp.39–40

173

C H A P T E R 12

Infection Control

Multiple Choice1. Whichofthefollowingdefinestheprocessesandprecautionsthatcanbetakentocontrol

thespreadofinfection?a. Chemicaldisinfectant.b. Aseptictechnique.c. Infectioncontrol.d. Surgerycleanliness.

2. Theclassificationofinfectioncontroldependsontheprocedurebeingperformedandriskofwhichofthefollowing?a. Contamination.b. Disinfection.c. Transmission.d. Splatter.

3. Treatingallpatientswiththesameprecautionsisthedefinitionofwhichofthefollowing?a. Routineprecautions.b. Standardoruniversalprecautions.c. Patientspecificprecautions.d. Procedurespecificprecautions.

4. HIVinfectioncanbetransmittedindentistrybywhichofthefollowing?a. Inhalationofinfecteddroplets.b. Contactwithcontaminateddentalunitwatersupplies.c. Contactwithskin.d. Useofinfectedinstruments.

5. Herpessimplextype1viruscanbetransmittedindentistrybywhichofthefollowing?a. Sharpsinjury.b. Contactwithskin.c. Inhalationofinfecteddroplets.d. Contactofinfectedmaterialwithskinoreyes.

6. Legionellaspp.canbetransmittedindentistrybywhichofthefollowing?a. Backsuctioning.b. Directinjectionofblood.c. Surface(skin)contactwithcontaminateddentalunitwater.d. Inhalationofinfecteddroplets.

174 12—InfeCtIon Control

7. MethicillinresistantStaphylococcus aureus(MRSA)hasbeenshowntohavebeentransmittedindentistrybywhichofthefollowing?a. Contactwithcontaminateddentalunitwatersupplies(DUWS).b. Infectedinstruments.c. Inhalationofinfecteddroplets.d. Contactwithskin.

8. Mycobacterium tuberculosishasbeenshowntohavebeentransmittedindentistrybywhichofthefollowing?a. Inhalationofinfecteddroplets.b. SkincontactwithcontaminatedDUWS.c. Directinjectionofblood.d. Infectedinstruments.

9. HepatitisB virushas been shown tohavebeen transmitted indentistry bywhichof thefollowing?a. Directinjectionofblood.b. Contactwithcontaminateddentalunitwatersupplies.c. Sharpsinjury.d. Inhalationofinfecteddroplets.

10. Microorganismspersist inDUWSasbiofilms.Whichofthefollowingisnotafeatureofthesebiofilms?a. Provideahavenforopportunisticpathogens.b. Cansloughoffandinfectpatients.c. Candisplayanincreasedsensitivitytodisinfectants.d. Cancontainoralbacteria.

11. Themostinfectiousagent,constantlypresentintheoralcavityofatleast30%ofthepopula-tion,iswhichofthefollowing?a. HepatitisBvirus.b. Coxsackieviruses.c. MRSA.d. Herpessimplextype1.

12. Theherpessimplexvirus is responsible forblindness indentalpersonnelduetowhichofthefollowing?a. Lackofavaccine.b. Notwearingadequateeyeprotection.c. Notusingvinylgloves.d. Sharpsinjury.

13. Important infection control elements of personal protection do not include which of thefollowing?a. Immunisation.b. Eyeprotection.c. Wearingcoverageoverhair.d. Avoidanceofsharpsinjuries.

12—InfeCtIon Control 175

14. Whichofthefollowingisnotarecommendedvaccinationfordentalpersonnel?a. Diphtheria.b. HepatitisB.c. Pneumonia.d. BCG.

15. Whichofthefollowingcanbeafactorincontactdermatitisfordentalpersonnel?a. Thoroughhandwashing.b. Latexrubbergloves.c. Non-thoroughhandwashing.d. Contaminationwithfungalagents.

16. Topreventthehandsfrombecomingvectorsofinfectionindentalprocedures,whichpro-tocolwouldnotbeadvised?a. Useofhandcreamaftereverysession.b. Useofalcoholanddisinfectanthandrubsifhandsarenotvisiblycontaminatedfollowing

patienttreatment.c. Limitthewearingofjewellery.d. Thoroughlydryingthehands.

17. Whatpercentageofdentalpersonnel in theUSAhavebeenestimatedtohavedetectableantibodiestolatexproteins?a. 10%.b. 40%.c. 65%.d. 75%.

18. Immunologicalcontactdermatitisrequireswhichofthefollowingtreatments?a. Morethoroughhandwashingprocedures.b. Anti-inflammatoryagents.c. Steroidorothersystemictherapy.d. Antibiotics.

19. Thetermusedtodescribethematerialthatiscoughedupbypatients,andwhichmayinfecttheeye,isknownaswhichofthefollowing?a. Inhalationdebris.b. Salivadebris.c. Biofilmdebris.d. Splatter.

20. Whichofthefollowingregimesisnotvalidatedtosteriliseasurgicalinstrument?a. 134°C/3min/2barpressure.b. 121°C/15min/1barpressure.c. 115°C/30min/1barpressure.d. 100°C/45min/1barpressure.


21. Thebestprotectionagainstaerosolsiswhichofthefollowing?a. Mask.b. High-vacuumsuction.c. Protectiveglasses.d. Gloves.

22. Whichofthefollowinghaveahighpotentialforthetransmissionofseriousinfection?a. Aerosols.b. Contactwithskin.c. Sharpsinjuries.d. Splatter.

23. Whichofthefollowingproceduresproducesthehighestpotentialforasharpsinjury?a. Bendinganeedle.b. Resheathinganeedle.c. Autoclavingbrokenglassware.d. Puttingcontaminatedglasswareintodisinfectant.

24. Inordertoreducetheriskofcrossinfectionmostsurgeriesincorporatethreedistinctareasorzones.Whichofthefollowingisnotoneofthesezones?a. Operator’szone.b. Decontaminationzone.c. Assistantzone.d. Patientzone.

25. Disinfectionistheremovalorkillingofsomemicroorganismsbutnotusuallywhichofthefollowing?a. Bacteria.b. Fungi.c. Spores.d. Bloodsplatter.

26. Disinfectionisreservedforfourdistinctplaces;theseare(a)surfaces,(b)drainsandspittoons,(c)dentalunitwatersupplies,andwhichofthefollowing?a. Impressionsandappliances.b. Lighthandles.c. Handpiece.d. Headofthex-raytube.

27. Whichofthefollowingisthemostimportantaspectofsurfacedisinfection?a. TheuseofanEnvironmentalProtectionAgency(EPA)-approvedproduct.b. Strengthofthedisinfectantused.c. Makingcertainthatthedisinfectantisbactericidal.d. Howtheproductisused.

28. Acombinationofabactericidaldisinfectantandwhichofthefollowingshouldbeusedondrainsandspittoons?a. Alcohol.b. Witchhazel.c. Antibiotics.d. Detergent.


29. WaterdeliveredfromDUWSisnotsterileandcancontainhighnumbersofopportunisticpathogens.WhichofthefollowinghasnotbeenidentifiedinoutflowingwaterfromDUWS?a. Legionella pneumophila.b. Mycobacteriumspp.c. MRSA.d. Pseudomonas aeruginosa.

30. Whichofthefollowingisthefinalstepinpreparingadentalapplianceandimpressionforalaboratoryprocedure?a. Rinsethemoffwithacommerciallyavailablemouthrinse.b. Brusheachwithadentifrice.c. Spraythesurfaceswithadisinfectant.d. Immerseinadisinfectant.

31. Theworddecontaminationisoftenmisused;itisdefinedasthetreatmentofaninstrumenttomakeitfitforre-use.Decontaminationthereforeinvolvesbothcleaningandwhichofthefollowing?a. Immersionindisinfectant.b. Sterilisation.c. Drying.d. Sprayingwithdisinfectant.

32. Thethreemethodscurrentlyusedforinstrumentcleaningindentistryaremanualwashing,washer/disinfectors,andwhichofthefollowing?a. Ultraviolet(UV)light.b. Deepimmersionoil.c. Ultrasonics.d. Surfacetension.

33. Whichofthefollowingistheleastefficientmethodofcleaninginstruments?a. Washer/disinfectors.b. Ultrasoniccleaning.c. Manualcleaning.d. UVlight.

34. Whichofthefollowingisthemostdifficulttokillduringthesterilisationprocess?a. Pathogenicmicroorganisms.b. Bacterialspores.c. Prions.d. Biofilms.

35. Indentistry,themostcommonprocessusedforsterilisationiswhichofthefollowing?a. Manualcleaning.b. Detergentbath.c. Autoclave.d. UVlight.


Feedback1. ANS:c

a. Chemicaldisinfectionispartofaninfectioncontrolprotocol,notthedefinitionofit.b. Usinganaseptictechniqueispartofaninfectioncontrolprotocol,notthedefinitionof

it.c. Correct. Infection control is defined as all the processes and precautions that can be

takentocontrolthespreadofinfection.d. Surgerycleanlinessispartoftheplatformofinfectioncontrol,butdoesnotdefineit.

REF:Infectioncontrol,p.204

2. ANS:ca. Contaminationistheresultofinfectiontransmission.b. Disinfectionisanendgoalofsomeinfectioncontrolprocedures,notariskfactor.c. Correct.Theclassificationofinfectioncontroldependsupontheprocedurebeingper-

formedandriskoftransmission.d. Spatterisameansoftransmissionofdisease,butnottheonlyone.


3. ANS:ba. The correct term for treating all patients with the same precautions is Standard or

UniversalPrecautions.b. Correct.Sincemostdentalpatientswhoasymptomaticallycarrydiseaseareunawareof

their infectiousstatus, it iswisetotreateveryonewiththesameprecautions; theseareoftendescribedasStandardorUniversalPrecautions.

c. Treating all patients with the same precautions is described as following Standard orUniversalPrecautions.

d. Procedure-specificprecautionsdoexist;however,whentheyareapplied,theyapplytoallpatients,notjusttosome.


4. ANS:da. CasesofHIVinfectiontransmittedindentistrythroughtheinhalationofinfecteddrop-

letshavenotbeendocumented.b. Cases of HIV infection transmitted in dentistry through contact with contaminated

dentalunitwatersupplieshavenotbeendocumented.c. CasesofHIVinfectiontransmittedindentistrythroughcontactwithskinhavenotbeen

documented.d. Correct.CasesofHIVinfectiontransmittedindentistryhavebeendocumentedasbeing

causedbyuseofinfectedinstruments.

REF:Whichinfectiousdiseasesaretransmittedbydentistry?,Table12.1,p.205


5. ANS:da. Herpessimplextype1virushasnotbeenshowntohavebeentransmittedindentistry

throughasharpsinjury.b. Herpessimplextype1virushasnotbeenshowntohavebeentransmittedindentistry

bycontactwithskin.c. Herpessimplextype1virushasnotbeenshowntohavebeentransmittedindentistry

throughinhalationofinfecteddroplets.d. Correct.Herpessimplextype1virushasbeenshowntohavebeentransmittedinden-

tistrybycontactofinfectedmaterialwithskinoreyes.


6. ANS:da. Legionella spp. have not been shown to have been transmitted in dentistry via back

suctioning.b. Legionella spp. have not been shown to have been transmitted in dentistry via direct

injectionofblood.c. Legionellaspp.havenotbeenshowntohavebeentransmittedindentistryviaskincontact

withcontaminateddentalunitwater.d. Correct.Legionellaspp.havebeenshowntohavebeentransmittedindentistrybyinhala-

tionofinfecteddropletsfromcontaminatedwaterindentalunitwatersystems.


7. ANS:da. MRSAhasnotbeenshowntohavebeentransmittedindentistrybycontactwithcon-

taminatedDUWS.b. MRSA has not been shown to have been transmitted in dentistry by use of infected

instruments.c. MRSA has not been shown to have been transmitted in dentistry by inhalation of

infecteddroplets.d. Correct.MRSAhasbeenshowntohavebeentransmittedindentistrybyskincontact.


8. ANS:aa. Correct.Mycobacterium tuberculosishasbeenshowntohavebeentransmittedindentistry

byinhalationofinfecteddroplets.b. PhysicalcontactwithcontaminatedDUWShasnotbeenshowntotransmitMycobacterium

tuberculosis.c. DirectinjectionofbloodhasnotbeenshowntotransmitMycobacterium tuberculosis.d. UseofinfectedinstrumentshasnotbeenshowntotransmitMycobacterium tuberculosis.

REF:Whichinfectiousdiseasesaretransmittedbydentistry?,p.205


9. ANS:ca. HIV,notHepatitisBvirus,hasbeenshowntohavebeentransmittedbydirectinjection

ofblood.b. Legionella spp.andPseudomonas aeruginosahavebeenshowntohavebeentransmittedby

contactwithcontaminatedDUWS.c. Correct. Hepatitis B virus has been shown to have been transmitted in dentistry by

sharpsinjury.d. Tuberculosis,nothepatitisBvirus,hasbeenshowntohavebeentransmittedbyinhalation

ofinfecteddroplets.


10. ANS:ca. Biofilms can be a haven from opportunistic pathogens, providing protection from

disinfectants.b. Biofilmscansloughoffthewallofthetubing,andinfectpatients.c. Correct.Biofilmsdisplayadecreasedsensitivitytodisinfectants.d. BiofilmsinDUWScancontainoralbacteria,derivedbyback-siphonagefromprevious

patients.

REF:Dentalunitwatersystems,p.209

11. ANS:da. Herpes simplex type 1, not hepatitis B virus, is the most infectious agent constantly

presentintheoralcavityofatleast30%ofthepopulation.b. Coxsackievirusisnotthemostinfectiousagentconstantlypresentintheoralcavityof

atleast30%ofthepopulation.c. MRSAisnotthemostinfectiousagentthatisconstantlypresentintheoralcavityofat

least30%ofthepopulation.d. Correct.Themostinfectiousagentthatisconstantlypresentintheoralcavityinatleast

30%ofthepopulationisHerpessimplextype1.


12. ANS:ba. Dentalpersonnelwhocontractherpessimplexvirusandexperienceblindnessdonotdo

sobecausetheydidnotgetvaccinated.b. Correct.Theherpessimplexvirushasbeenresponsibleforblindness,usuallyindental

personnelwhodonotwearprotectivespectaclesforeyeprotection.c. Indentalpersonnelwhocontractherpessimplexvirusandexperienceblindness,itisnot

relatedtonotwearingprotectivegloves.d. Indentalpersonnelwhocontractherpessimplexvirusandexperienceblindness,itisnot

relatedtoasharpsinjury.



13. ANS:ca. Immunisationisanimportantpartofinfectioncontrolmeasures.b. Eyeprotectionisanimportantpartofinfectioncontrolmeasures.c. Correct.Wearingcoverageoverhair isnotoneof the importantelementsofpersonal

elementsofinfectioncontrol.d. Avoidanceofsharpsinjuriesisanimportantpartofinfectioncontrolmeasures.

REF:Immunisation,p.205

14. ANS:ca. Diphtheriaisarecommendedvaccinationfordentalpersonnel.b. HepatitisBisarecommendedvaccinationfordentalpersonnel.c. Correct.Pneumoniaisnotarecommendedvaccinationfordentalpersonnel.d. BCGfortuberculosisisarecommendedvaccinationfordentalpersonnel.


15. ANS:ba. Thoroughhandwashing,whileanimportantaspectofinfectioncontrol,isnotcauseof

contactdermatitis.b. Correct. Latex rubber gloves can cause contact dermatitis because they contain low

molecular weight proteins that can be immunologically active. These low molecularweightproteinscanpenetratetheskinandinduceinflammation;thisconditioniscalledirritantcontactdermatitis.

c. Non-thorough hand washing which is never appropriate is not the cause of contactdermatitis.

d. Contaminationwithfungalagentsisnotcauseofcontactdermatitis.

REF:Immunisation,pp.205–206.

16. ANS:ca. Useofhandcreamaftereverysessionisadvisedtoprotectskinfromdrying.b. Useofalcoholanddisinfectanthandrubsifhandsarenotvisiblycontaminatedfollowing

patienttreatmentisrecommended.c. Correct.Alljewelleryistobeeliminated,notmerelylimited.d. Thorough drying of the hands protects them from further drying out when wearing

gloves.

REF:Handprotection,pp.205–207

17. ANS:ba. IntheUSA,ithasbeenestimatedthat40%ofmedicalpersonnelhavedetectableanti-

bodiestolatexproteins.b. Correct.IntheUSA,ithasbeenestimatedthat40%ofmedicalpersonnelhavedetect-

ableantibodiestolatexproteins.c. IntheUSA,ithasbeenestimatedthat40%ofmedicalpersonnelhavedetectableanti-

bodiestolatexproteins.d. IntheUSA,ithasbeenestimatedthat40%ofmedicalpersonnelhavedetectableanti-

bodiestolatexproteins.

REF:Gloves,p.207


18. ANS:ca. Handwashingisnotaneffectivetreatmentforimmunologicalcontactdermatitis.b. Anti-inflammatory agents are not an effective treatment for immunological contact

dermatitis.c. Correct.Immunologicalcontactdermatitisrequirestopicalsteroidsastherapy.d. Antibioticsarenotaneffectivetreatmentforimmunologicalcontactdermatitis.

REF:Gloves,p.207

19. ANS:da. Themethodofcontaminationthroughbreathingiscalledinhalation.Spatteristheterm

used for contaminated blood and saliva, coughed by a patient into the face of anoperator.

b. Spatter is the termused forcontaminatedbloodandsaliva, coughedbyapatient intothefaceofanoperator.

c. Spatter is the termused forcontaminatedbloodandsaliva, coughedbyapatient intothefaceofanoperator.

d. Correct.Spatteristhetermusedforcontaminatedbloodandsaliva,coughedbyapatientintothefaceofanoperator.

REF:Eyeandfaceprotection,p.208

20. ANS:da. 134°C/3min/2barpressureisvalidatedtosteriliseasurgicalinstrument.b. 121°C/15min/1barpressureisvalidatedtosteriliseasurgicalinstrument.c. 115°C/30min/1barpressureisvalidatedtosteriliseasurgicalinstrument.d. Correct. 100°C/45min/1 bar pressure is not validated to sterilise a surgical

instrument.

REF:SterilizationofInstruments,Table12.3,p.211

21. ANS:ba. Afacemasqueisameansofprotectionfromaerosols,butnotthebestmeans.b. Correct.Thebestprotectionagainstaerosolsishigh-vacuumsuction.c. Protectiveglassesarenotthebestprotectionagainstaerosols.d. Glovesarenotthebestprotectionagainstaerosolsinhigh-vacuumsuction.

REF:Eyeandfaceprotection,p.208

22. ANS:ca. Aerosolsdonotholdahighpotential for thetransmissionofserious infectionas they

donotinvolvebloodtobloodcontact.b. Contactwithskindoesnotholdahighpotentialforthetransmissionofseriousinfection

asitdoesnotinvolvebloodtobloodcontact.c. Correct.Sharpsinjuriesholdahighpotentialforthetransmissionofseriousinfection

astheycaninvolvebloodtobloodcontact.d. Splatterdoesnotholdahighpotentialforthetransmissionofseriousinfectionasitdoes

notinvolvebloodtobloodcontact.

REF:Gloves,p.208


23. ANS:ba. Accordingtoinfectioncontrolpractices,needlesshouldnotbebentpriortodisposal.b. Correct. Inoculation injuries (often called sharps or needlestick injuries) have a high

potential for the transmission of serious infection as they can involve blood to bloodcontact,andresheathingofneedlesisapotentiallyriskyprocedure.

c. Resheathingofneedlesispotentiallythemostriskyprocedureforsharpsinjuries.d. Resheathingofneedlesispotentiallythemostriskyprocedureforsharpsinjuries.

REF:Inoculationinjuries,p.208

24. ANS:da. Inorder to reduce the riskof cross infectionmost surgeries incorporate threedistinct

areasorzones:anoperator’szone,anassistantzone,andadecontaminationzone.b. Inorder to reduce the riskof cross infectionmost surgeries incorporate threedistinct

areasorzones:anoperator’szone,anassistantzone,andadecontaminationzone.c. Inorder to reduce the riskof cross infectionmost surgeries incorporate threedistinct

areasorzones:anoperator’szone,anassistantzone,andadecontaminationzone.d. Correct.Inordertoreducetheriskofcrossinfectionmostsurgeriesincorporatethree

distinctareasorzones:anoperator’szone,anassistantzone,andadecontaminationzone.A‘patientzone’isnotidentified.

REF:Surgerydesign,p.209

25. ANS:ca. Disinfectionnormallykillsmostbacteria.b. Disinfectionnormallykillsmostfungi.c. Correct.Disinfectionistheremovalorkillingofsomemicroorganismsbutnotusually

spores.d. Disinfectionnormallyremovesbloodsplatter.

REF:Surgerydisinfection,p.209

26. ANS:aa. Correct.Disinfectionisreservedforfourdistinctplaces;theseare(a)surfaces,(b)drains

andspittoons,(c)dentalunitwatersupplies,and(d)impressionsandappliances.b. Disinfection is reserved for four distinct places; these are (a) surfaces, (b) drains and

spittoons,(c)dentalunitwatersupplies,and(d)impressionsandappliances.c. Disinfection is reserved for four distinct places; these are (a) surfaces, (b) drains and

spittoons,(c)dentalunitwatersupplies,and(d)impressionsandappliances.d. Disinfection is reserved for four distinct places; these are (a) surfaces, (b) drains and

spittoons,(c)dentalunitwatersupplies,and(d)impressionsandappliances.

REF:Surgerydisinfection,p.209


27. ANS:da. Althoughalargenumberoftypesofsurfacedisinfectantareavailable,howaproductis

usedisprobablymoreimportantthantheirdisinfectantclassification.b. Althoughalargenumberoftypesofsurfacedisinfectantareavailable,howaproductis

usedisprobablymoreimportantthanthestrengthofdilution.c. Althoughalargenumberoftypesofsurfacedisinfectantareavailable,howaproductis

usedisprobablymoreimportantthanthemodeofaction.d. Correct.Althoughalargenumberoftypesofsurfacedisinfectantareavailable,itishow

theyareusedthatisprobablymoreimportantthantheirdisinfectantaction.

REF:Surfacedisinfection,p.208

28. ANS:da. Alcoholshouldnotbeusedforadisinfectantfordrainsandspittoons.b. Witchhazelshouldnotbeusedforadisinfectantfordrainsandspittoons.c. Antibioticsshouldnotbeusedforadisinfectantfordrainsandspittoons.d. Correct.Acombinationofabactericidaldisinfectantanddetergentshouldbeusedon

drainsandspittoons.

REF:Drainsandspittoons,p.209

29. ANS:ca. WaterdeliveredfromDUWScancontainL. pneumophila.b. WaterdeliveredfromDUWScancontainmycobacteria.c. Correct.MRSAhavenotbeenreportedinwaterdeliveredfromDUWS.d. WaterdeliveredfromDUWScancontainP. aeruginosa.

REF:Dentalunitwatersystems,p.209

30. ANS:da. Rinsingoffappliancesandimpressionswithacommerciallyavailablemouthrinseisnot

aneffectivewaytodisinfectappliancesandimpressions.b. Brushingappliancesandimpressionswithadentifriceisnotaneffectivewaytodisinfect

appliancesandimpressions.c. Sprayingthesurfaceswithadisinfectantisnotaneffectivewaytodisinfectappliances

andimpressions.d. Correct. Before leaving the surgery, appliances and impressions should be washed to

removedebrisandthenimmersedinadisinfectant.

REF:Disinfectionofappliancesandimpressions,p.210

31. ANS:ba. Disinfectingdoesnotprovidethesamesafetyassterilisation.b. Correct.Theworddecontaminationisoftenmisused;it isdefinedasthetreatmentof

aninstrumenttomakeitfitforre-use.Decontaminationthereforeinvolvesbothcleaningandsterilisation.

c. Dryinganinstrumentdoesnotprovidethesamesafetyassterilisation.d. Sprayinganinstrumentwithdisinfectantdoesnotprovidethesamesafetyassterilisation.

REF:Decontaminationofinstruments,p.210


32. ANS:ca. UVlightisnotoneofthethreemethodsusedforinstrumentcleaningindentistry.b. Deep immersion oil is not one of the three methods used for instrument cleaning in

dentistry.c. Correct.Thereare threemethodscurrentlyused for instrumentcleaning indentistry;

theyaremanualwashing,washer/disinfectorsandultrasonics.d. Surface tension is not one of the three methods used for instrument cleaning in

dentistry.

REF:Criticalandnon-criticalinstruments,p.211

33. ANS:ca. Washer/disinfectorsareanefficientmethodofcleaninginstruments.b. Ultrasoniccleaningisanefficientmethodofcleaninginstruments.c. Correct. Manual cleaning is the least efficient method of cleaning instruments, and

carriesariskofasharpsinjury.d. UVlightisnotarecommendedmethodofcleaninginstruments.

REF:Manualcleaning,p.211

34. ANS:ca. Pathogenicmicroorganismsarekilledduringsterilisation.b. Sporesarekilledinthesterilisationprocess.c. Correct. Prions are resistant to strong disinfectants, heat, autoclaving, and enzyme

activity.d. Biofilms should be removed by efficient cleaning, and any residual bacteria are killed

duringsterilisation.

REF:Transmissiblespongiformencephalopathies,p.199

35. ANS:ca. Manualcleaningdoesnotsterilise.b. Detergentbathdoesnotsterilise.c. Correct.Indentistry,themostcommonprocessusedforsterilisationistheautoclave.d. UVlightdoesnotsterilise.

REF:Sterilisationofinstruments,p.211

187

I N D E X

Indextoquestionsubjects.Readersareadvisedtoalsorefertotherelevantanswers.

Aabscess 102

dentoalveolar 102–105,159periodontal 103

aceticacid 63aciclovir 82,143–144,146Actinomyces 61,77,101,107Actinomyces naeslundii 23actinomycosis,cervicofacial 101–102,105,107adhesin(s) 43–44,60,120adhesin-receptorinteractions 60adhesionofmicrobes 43,60–62,83aerobes 8aerosols,protectionagainst 176ageing 39–40,77Aggregatibacter actinomycetemcomitans 24,

80–81AIDSseeHIVinfection/AIDSallogenicsuccession 39AmericanTypeCultureCollection 21amoxicillin 81,102,119,121amylase 7,44anaerobes 8,41,43,45,155–162

black-pigmented 23,39facultative 42,62obligate 39–40,61,78–79,

102,156angularcheilitis 107,133antagonisticinteractions 64antibiotic(s) 104,118–122,157

broadspectrum 44,132intravenous 121resistance 10,61,102–103,118–122

antifungalagents 134antimicrobialagent(s) 9–10,59,84–85,120

biofilmcelltoleranceto 61–62maximumconcentrations 120penetrationofbone 119,121prophylactic 118–129selection 119

antimicrobialpeptides 134antirejectionagents 159antiretroviraltherapy 158,161antiviraldrugs 143–144artificialsweeteners 82aspirationoforalmicrobes 160autoclaves 177

Bbacteraemia 121–122bacterialcellcommunication 60bacterialdensity 42–43bacterialovergrowth 5bacteriocins 63BCGvaccine 161beta-lactamaseproducers 103biofilm 2,5–10,20–26,41,59

antimicrobialtolerance 61–62dentalunitwatersystems 174formation 60–62properties 59,62,64structure,studytechniques 41

bisphosphonates 158bloodagar 23,41bone

antimicrobialpenetration 119,121bisphosphonatesand 158radiationdamageandnecrosis 156–157

bufferingsystem 7Burkitt’slymphoma 147

Ccalciumloss 158calculus 63cancrumoris(noma) 82–83,158–159Candida 26,40,42,107,130–134

colonisationby 130hydrolyticenzymes 131secondarylesions 133

Candida albicans 25,40,130–131candidosis(oral) 130–131,134,161

acuteerythematous 132chronicerythematous 134chronichyperplastic 132–133chronicmucocutaneous 133predisposingfactors 133–134,140–142

Capnocytophaga gingivalis 22capnophilicbacteria 22carbohydrate(s) 24

fermentable 8–9,21,44,76metabolism/fermentation 44,76

carbondioxide 22,38,61caries,dental 7,22,24,75–100,104

enamel 24,76–77process 76root-surface 24,76–77secondary 77

cariogenicpotential 24

188 INDEX

CD4+lymphocytes 158,160cell–cellsignalling 64cellmediatedimmunity 40,133cellulitis 102cervicofacialactinomycosis 101–102,105,107chemotaxonomy 20chewinggum 85children 82–83,107chlorhexidine 10,82,84–85,105classificationofmicroorganisms 20–21cleaningofinstruments 177coldsores(herpeslabialis) 145–146colonisation(microbial) 1,5–6,24,37–58

fungal 130resistance 44

colonycounting 41competition,bacterial 43,63confocalmicroscopy 41contactdermatitis 175contaminationofsamples 102,106Coxsackievirus 147cross-infectionprevention 176cryptitopes 60culture,ofmicrobes 21,25,40–41culturemedium 41cytokines 105

Ddecontamination 157,177defensins 9demineralisation 76dentalappliances,preparation 176–177dentalunitwatersystems(DUWS) 174,177dentoalveolarabscess 102–105,159dentoalveolarinfection 103dentures 42,134detergents 176diabetesmellitus 82,134disinfectants 174,176disinfectionprocess 176DNAextraction 21DNA-DNAhybridisation 42drugaddicts 122drysocket 101

Eecologicalplaquehypothesis 75,80ecology,microbial 1–2,5–19electronmicroscopy 62,143enamel 5,24,60,76endocrinedisorders 156endodonticinfections 103endotoxin 103

enolase 41,59epidemiologicalsurveys 76Epstein–Barrvirus(EBV) 146–147erythromycin 103exopolymer 21eyeprotection 174

Ffaciallacerations 105fasting 44fermentationofcarbohydrates 21fluorapatite 84fluoride 76,82,84foetus 37foreignmaterial,inperiodontalpocket 103fructan 21–22fungalinfections 130–142fungalmicroflora 25fungalspores 176

Ggenetransfer 64gingiva 6gingivalcrevice 6,23,39,62,77gingivalcrevicularfluid(GCF) 7–8,80–81gingivalhyperplasia 156,159gingivitis 78–79

chronicmarginal 78herpetic 144pregnancy 82

glossitis,medianrhomboid 133glucan 22,45glycogen 44glycosidase 8,63Gramnegativebacteria 25,39,80,

155–162anaerobes 45,79cocci 24–25overgrowth 5

Grampositivecocci 23Gramstaining 41

HHAARTseehighlyactiveantiretroviraltreatmenthabitat 1–2,5–19hairyleukoplakia 146halitosisseeodour,mouthhand,footandmouthdisease 147H+/ATPase 43Helicobacter pylori 1hepatitisB/hepatitisBvirus 161,174herpangina 147

INDEX 189

herpeslabialis(coldsores) 145–146herpessimplextype1(HSV-1) 26,82,174

primaryinfection 144reactivation/recurrence 145–146transmission 173treatment 82,144

herpesviruses 144herpeticgingivitis 144highlyactiveantiretroviraltreatment

(HAART) 158,161histatins 134HIV(humanimmunodeficiencyvirus) 158,161HIVinfection/AIDS 80,131,155,160–161

transmission 173homeostasis,microbial 39,64homeostatichypothesis 75hostdefencesystem 1,5–6,9,83

evasion 39humanherpesvirus8(HHV-8) 144,147humanpapillomavirus(HPV) 147hyphae 131

Iidentification,ofmicrobes 21,41IgA,secretory(sIgA) 5,10IgA1protease 38IgM(immunoglobulinM) 7immunocompromisedpatients 155–172immunosuppression 151impressions,preparation 176–177infectedjointreplacements 120–121infectioncontrol 173–185infectiousmononucleosis 146infectiveendocarditis 118,120–122inflammation 8,77,79,102,104–105,122innateimmunity 9intergenericcoadhesion 60

Jjewellery,wearingof 175jointreplacements 120–121

KKaposi’ssarcoma 147Kaposi’ssarcomaherpesvirus(HHV-8) 144,147Koch’spostulates 75–85

Llactate 64Lactobacillus 9,24,157

enameldentalcaries 77root-surfacecaries 77

latentinfections 144

latex,antibodiesanddermatitisdueto 175lectin-mediatedinteraction 61Legionella,transmission 173lipoteichoicacid(LTA) 120lymphadenitis 104,107lysozyme 6

Mmalodourseeodour,mouthmaxillo-facialinfections 23metabolism(microbial) 7,9,37–58,64,76methicillinresistantStaphylococcus aureus

(MRSA) 174,177metronidazole 81microbialecology 1–2,5–19microflora,resident 1,20–36

composition 21determiningcomposition 40–41fungal 130–134lossoforalmusculatureand 155

microorganismnumber 2minimuminhibitoryconcentration(MIC) 106molecularanalysis 21,40,42,155–162mother,microbetransferfrom 37–38,77mouthrinse/mouthwash 10,85mucins 6,8,63mucositis 159

post-irradiation 155,157mutansstreptococci 22,38,44,157

caries 77Mycobacterium tuberculosis,transmission 174Mycoplasma 26

Nnecrotisingfasciitis 156,159necrotisingulcerativegingivitis(NUG) 80–81Neisseriaspecies 24,61neurologicaldisorders 156neutrophils 6,8,81,83newborn,microbialcolonisation 37–38,77noma(cancrumoris) 82–83,158–159nutrients,microbial 6,9

competitionfor 63salivacomponentsas 7supplyformicroflora/pathogens 44,62,101

Oodour,mouth 25,39,42,45,101opportunisticpathogens 23,107,133,156oralcancer 132,156oraldisease,spread 2oralhealthcare,disparities 2

190 INDEX

oralmusculature,loss 155,159orofacialbacterialinfections 101–117osteomyelitis,ofjaw 104osteoporosis 158osteoradionecrosis 156–157oxidation-reductionpotential 8,38oxygen 8,20–26,61

Ppalate 42Parkinson’sdisease 155,159parotidgland 106parotitis,suppurative 106passiveinoculation 37–45pathogens 1pellicles 43,59–60penicillins 102–103PEP-PTS(phosphoenolpyruvate-mediated

phosphotransferase) 44pericoronitis 105–106peri-implantitis 105periodontalabscess 103periodontaldestruction,enzymes 83periodontaldisease 24,75–100

generalhealthand 84periodontalpocket 40,43,77–78,80,103

temperature 8periodontitis 79,101–107

acute 78aggressive 78,80–81chronic 78–79,84

personalprotection 174pH 7,9,20–26,43,77–78phagocytosis 119phospholipases 131pioneerspecies 38,60plaque,dental 20–26,59–74,101–107

animal 62diseasesmediatedby 75–100doublingtime 61hypotheses 75,80maturation 22subgingival 25vortexing,ofsample 41

plaquefluid 62pneumonia 78,160,175polymicrobialinfections 101,103polyols 85Porphyromonas 155–162Porphyromonas endodontalis 25Porphyromonas gingivalis 9,23,80,83post-irradiationmucositis 155post-operativeinfections 118–121pregnancy 82

Prevotellaspecies 25,82,155–162prions 160–161,177propionicacids 63protozoa 20Pseudomonas aeruginosa 1puberty 39pulmonaryinfections 5,78,160pulpdeath 104pus,aspiration 101–102,106pyostomatitisvegetans 158pyrexia 5pyrophosphate 63

Qquorumsensing 60

Rradiationdamage 156remineralization 76respiratorypathogens 1reversetranscriptase 160rootplaning 81–82

Ssaliva

bacterialdensity 42bufferingsystem 7components 6–7,10flow 40,60,130gingivalcrevicularfluid,comparison 7microbialcolonisationcontrol 6

salivaryglands 7,106salivarytests 83samplingtechniqueforinfections 101secondaryfeeder 64secretedaspartylproteinases

(ASPs) 131sharpsinjury 174,176shingles 146sialadenitis 106Sjögren’ssyndrome 106smoking 40,132species 21specificplaquehypothesis 75spirochaetes,oral 24–25,39splatter 175standard(universal)precautions 173staphylococci 105,118,122,158

lymphadenitis 104sterilisation,ofinstruments 175,

177steroidinhalers 132,134

INDEX 191

streptococci(Streptococcus) 1,20,22–23,42,61,120

adhesins 44facultativeanaerobes 42mutansseemutansstreptococcipioneercommunity 38

Streptococcus intermedius 23Streptococcus mutans 22,43,63,80 see also

mutansstreptococcimetabolism 45

Streptococcus pyogenes 23Streptococcus salivarius 21,23,37Streptococcus sanguinis 120Streptococcus sobrinus 20,76Streptococcus vestibularis 23stroke 155,159–160subgingivalcalculus 63subgingivalenvironment 78subgingivalplaquesamples 6submandibulargland 106succession,ofmicroorganisms

38–39,60,62sugars,fermentation 20,63sugarydrinks/food 7sulphate-reducingbacteria 25sulphurgranules 105surgicaldrains 104surgicalsiteinfections 118–119swallowing 9synergisticmicrobialinteractions 63syphilis 162

Ttemperature

oralcavity 8periodontalpocket 8

tissuedamage,bypathogens 83tongue 42,133

asmicrobialhabitat 5,26whitelesionsonborder 146

tootheruption 39toothsurface 22

caries 76lowestmicrobialcommunity 7protectionagainstmicroorganisms 6

transmissiblespongiformencephalopathies(TSEs) 160–161

transmission,ofinfections 173–174,176vertica 37–38,77

transport,microbial 60trauma 104–105Treponema 24Treponema denticola 104Treponema pallidum 162Trichomonas tenax 20triclosan 85trigeminalganglion 145tuberculosis 161twins,microflora 10

Uultrasoniccleaning 177urea 38

Vvaccination 175valvularinsufficiency 122VanderWaalsforces 61varicellazostervirus(VZV) 146,161Veillonella 25,63verticaltransmission 37–38,77vestibularmucosa 23viralinfections(orofacial) 143–154virulencefactors 81,83,131viruses 26,143see alsonamesof

specificviruses

Wwhitebloodcells 155woundinfections,oral 119

Xxerostomia 64,106,157,159

Yyeasts,overgrowthby 10

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