2002 dentine hypersensitivity bleaching and restorative considerations for successful management

7/28/2019 2002 Dentine Hypersensitivity Bleaching and Restorative Considerations for Successful Management

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International Dental Journal (2002) 52, 710

2002 FDI/World Dental Press0020-6539/02/05000-09

Dentine hypersensitivity: bleachingand restorative considerations forsuccessful management

Van B. HaywoodAugusta, USA

The presenting symptoms of sensitive teeth are multi-factorial, and from theperspective of restorative dentistry, make a differential diagnosis of truedentine hypersensitivity a challenge. This paper discusses the commoncauses of tooth sensitivity, focusing on restorative (operative) aspects andtooth whitening (bleaching). Restorative strategies for managing the condi-tion and recommended dental materials are reviewed.

Key words: Sensitive, hypersensitive, restorative dentistry, tooth bleaching

Correspondence to: Van B. Haywood. Department of Oral Rehabilitation, Medical College,Georgia School of Dentistry, 15th Street, Augusta, GA 30912-1000, USA.E-mail: [email protected]

Historically, probably the mostcommon concern that brings peopleto the dental practice is a tooth thathurts. A diagnosis of the cause oftooth sensitivity can range from anabscessed or cracked tooth (Figure1), to dental decay or some formof hypersensitivity. Symptoms of onecondition can often be confused

with another, and pain level can bedirectly or indirectly related toseverity of the cause. This paper

will discuss the causes of sensitiveor hypersensitive teeth that thedentist may encounter, and possi-ble treatments from a restorativeperspective. The focus will be onsensitivity problems with no obvi-ous pathology.

A differential diagnosis of sensi-tivity must take into considerationa number of variables (Table 1),such as problems with the tooth(Figure 2), problems with the

surrounding periodontium, insultsto the tooth and predisposingconditions.

When the patient presents withsensitivity, the first step in manage-ment is to take a complete historyof the condition. Essential infor-mation to be assessed includes: The history and nature of the

pain (sharp, dull, or throbbing) The number and location of

sensitive teeth, and whether the

same teeth are always involved The area of the tooth from

which the sensitivity originates The intensity of the pain (on a


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International Dental Journal (2002) Vol. 52/No.5 (Supplement 1)

Table 1

1. Abscessed or non-vital tooth. With periapical radiolucency or draining fistula; necrotic with sensitivity to occlusion;

partially necrotic in one canal, with vital tissue elsewhere (in which case tooth tests vital to stimuli). Pain typically

occurs spontaneously or upon occlusion or tapping.

2. Cracked tooth. Vertical fracture or single cusp partial fracture. Pain typically occurs on release of biting or tapping of

a single cusp (Figure 1).

3. Dental caries. Greatest degree of sensitivity experienced when dental decay passes the dentine-enamel junction. As

caries penetrates further into the tooth, sensitivity lessens until pulp becomes involved.

4. Gingival recession. Often occurs post-periodontal surgery, when a large portion of the root is exposed, or due to

ageing, mechanical trauma, fraenum attachment pull or occlusal trauma (Figure 3).

5. Toothbrush abrasion. Caused by use of a hard toothbrush or a soft toothbrush with abrasive toothpaste or by

aggressive brushing, and generally located on the side opposite the dominant hand. Abrasion may either instigate

gingival recession or stem from greater accessibility to softer root surfaces from recession.6. Abfraction lesions. Generally associated with occlusal trauma where the anatomic crown of the tooth has flexure.

Although non-carious, these lesions can become very sensitive and even progress into the pulp. They may be multi-

factorial where abrasion and erosive forces combine to produce tooth surface loss (Figure 46).

7. Erosive lesions. Associated with acid reflux, hiatus hernia, purging, bulimia (intrinsic causes), and diet (extrinsic

causes). Intrinsic acid lesions typically occur on the palatal surfaces, while extrinsic acid lesions tend to occur on the

buccal surfaces. Consuming large quantities of carbonated cola drinks and fruit drinks, which have a very low pH,

causes tooth surface loss1-3, as does toothbrushing following an acidic assault, which removes the acid-softened

enamel or dentine.

8. Diet sensitivity. Generally associated with a low pH material, such as fresh tomatoes, orange juice, cola drinks4-6.

Areas with exposed dentine are etched, causing sudden sensitivity. Diet choices may aggravate sensitivity from

erosion.

9. Genetic sensitivity. Patients reporting history of sensitive teeth. It is not known whether sensitivity correlates to the

10 per cent of teeth that do not have cementum covering all the dentine at the DEJ 7, or is a factor of lower overall

patient pain threshold values.

10. Restorative sensitivity. Triggered following placement of a restoration for several possible reasons: certain

amalgams (such as Tytin) having a history of 2448 hours sensitivity due to shrinkage, rather than the usual expansion,

during setting; contamination of composites during placement or improper etching of the tooth on composites, which

results in micro-leakage; improper tooth-drying technique; incorrect preparation of glass ionomer or zinc phosphate

cements; general pulpal insult from cavity preparation technique; thermal or occlusal causes; galvanic reaction to

dissimilar metals that creates a sudden shock or tin foil taste in the mouth.

11. Medication sensitivity. Due to medications that dry the mouth (e.g. antihistamines, high blood pressure medication),

thereby compromising the protective effects of saliva and aggravating diet-related trauma or proliferating plaque. Even

a reduction in salivary flow due to ageing or medications can lower the pH of the saliva below the level at which caries

occurs (6.06.8 for Dentine caries; < 5.5 for enamel caries) and increase erosive lesions to exposed dentine8.

12. Bleaching sensitivity. Commonly associated with carbamide peroxide vital tooth bleaching9 and thought to be due to

the by-products of 10 per cent carbamide peroxide (3 per cent hydrogen peroxide and 7 per cent urea) readily passing

through the enamel and dentine into the pulp in a matter of minutes11. Sensitivity takes the form of a reversible pulpitiscaused from the dentine fluid flow and pulpal contact of the material, which changes osmolarity, without apparent harm

to the pulp. Sensitivity is caused by all other forms of bleaching (in-office, with or without light activation, and new,

over-the-counter) depends on peroxide concentration.

Figure 1. Cracked tooth. Upon removal of a large amalgam restoration for which the patient complained of sensitivity to biting, a fracturewas noted from mesial to distal


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Haywood: Dentine hypersensitivity: bleaching and restorative considerations

Figure 3. Gingival Cleft may be associated with abnormal occlusion

Figure 4. Abfraction: In this heavy bruxer, the notched-shapedlesions are located sub-gingivally. The tissue must be displaced toaccess the lesions, indicating the toothbrush abrasion is not theprimary cause of the defect

Figure 5. Abfraction lesions in the subgingival area measured 23mm in horizontal depth, and had a chisel shaped form

Figure 6. Chemical Erosion after Abrasion: Once this bruxer has

removed the protective covering of enamel, the exposed dentinmay be dissolved by saliva or drinks with a pH lower than 6.8 buthigher than 5.5 (where the enamel is affected). Restorative carewould be to etch, prime and bond the dentin to the enamel withoutaltering the occlusion to retard the wear of the tooth

Figure 2.


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International Dental Journal (2002) Vol. 52/No.5 (Supplement 1)

Table 2 List of potential agents, restorative materials or procedures for use in the

management of dentine hypersensitivity

Reversible Non-reversible

Desensitising toothpastes Glass ionomer cements

Fluoride gels, rinses, and varnishes Resins, filled or unfilled

Oxalates of ferric, aluminium and potassium Periodontal flaps or grafts

Protein precipitants Pulp extirpation and root canal filling

110 scale, where 1 = mild, and10 = intolerable) and anychanges an increase, decreaseor no change in intensity ofthe pain

The trigger or stimulus whichinitiates the sensitivity

The frequency and duration of

each episode Other related events, such asrecent restorative or periodon-tal and hygiene treatments,change in diet or oral hygieneaids or regimen, or homebleaching.

A thorough clinical examinationshould follow the interview, andinclude an objective evaluation ofthe following factors: Does tactile examination with a

dental explorer elicit pain, andcan the pain be localised to onearea or one tooth?

Is the area or tooth sensitive togentle flow of air from the air-

water syringe? Is the tooth sensitive to percus-

sion? Is there sensitivity to biting pres-

sure or upon release? What is the duration of pain

after stimuli?

Does radiographic examinationreveal caries or periapical pathol-ogy?

Is dentine exposed (gingivalrecession, loss of attachment,loss of enamel, or abfraction)

Is there evidence of crackedcusps, fractured or leaking res-torations, or occlusal interfer-ence and hyperfunction, or brux-ism?Once the cause is determined,

treatment options can be consid-ered. Options can be non-reversibleor reversible (Table 2) or a combi-nation of both depending upon

Figure 7. Tooth Mobility:Evaluation of fremitus (tooth mobility) can be done by placing theforefinger lightly on the buccal of pairs of the teeth and asking the patient to grind around.Differences of mobility can be noted during movements.

Figure 8. Tooth mobility: In the previous patient exhibiting fremitus, the occlusion washeavier on the first premolar than on the canine, and the premolar moved during excursivemovements. Red articulating marks indicate functional guidance (and should be removed),blue indicates maximum intercuspation

severity and extent of the condition.

Treatment options

In the case of abscessed teeth,cracked teeth or dental caries,removing the cause can involve:endodontic therapy, oral surgery

(extraction, root resection or apicalsurgery), or replacing the restora-tion and broken cusp.

When a restoration is indicated,

preventing sensitivity can take theform of base placement (such as

Vitrabond for thermal sensitivity)or sealing dentine tubules with aprime and bond system (as found

with any composite bonding system).Sensitivity can be reduced by cleans-ing the cavity preparation with a

chlorhexidine solution to reducebacterial insult, sealing tubules witha HEMA and glutaraldehyde mate-rial (e.g. Gluma) or selecting materi-


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als that have no history of inducingthis condition (e.g. composite resininstead of amalgam).

Techniques for cementation ofcrowns, which preclude over-dry-ing of the tooth where glass

ionomer cements are employed,may be helpful in avoiding sensi-tivity. Depending on the cementused, dentine tubules can be sealedunder crowns with prime andbond, HEMA/gluteraldehyde orsimple copal varnish. If occlusaltrauma is suspected (Figure 7), adjust-ing the occlusion (Figure 8) orinserting a splint may be beneficial.Cervical lesions from abrasion orabfraction may require restorationsfor thermal protection, as opposedto application of a desensitisingmaterial alone. Some sensitivityassociated with new compositerestorations is due to placementtechniques and bulk cure of highpolymerisation-shrinkage materials.

The C-factor, or ratio of boundsurfaces to unbound surfaces, canhelp determine the potential forsensitivity and suggest a possiblechange in placement techniquesto minimise the effects of poly-merisation shrinkage. A Class I orClass V cavity preparation has thehigh-est C factor (5) and the great-est chance for post-operative sensi-tivity but is also often used throughaesthetic necessity to treat existingsensitivity. Techniques that can mini-mise the chance of exchangingone type of sensitivity for anotherthen include avoiding bulk filling,

placement of a stress breaker linersuch as Optibond II or Vitrabond,and soft-start curing lights12.

Abfraction lesions may requireadjustment of the occlusion(usually elimination of the functioncontacts other than those in maxi-mum inter-cuspation), followedby placement of a microfilledcomposite, which offers some flex-ibility with the tooth movement.

A higher fai lure rate has been

reported in Class V compositebonding of non-carious cervicallesions when the composite isplaced in an untreated abfraction

Figure 9. Blue is maximum intercuspation; red is function. The premolar has heavy functionrather than anterior guidance. There is evidence of parafuctional habits on all the teeth

Figure 10. Heavy function on the premolar (Figure 9) has produced a non-cariousabfraction lesion. The patient complained of sensitivity, so a composite restoration wasplaced. It debonded (failed) in a few weeks. Proper treatment would be to adjust theocclusion on the first premolar (and the molar), then replace the restoration

Figure 11. Observation of the patient in function shows contact on the first premolar butnot on the second premolar. Splint therapy may be indicated for parafunctional habits

lesion, emphasising the need tomodify the occlusion and reducethe abfraction forces (Figures 911).

Root surfaces that have beenexposed from erosion and/orabrasion, (sometimes described astoothbrush trauma) can often be


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recovered by periodontal flap orgraft surgery, but only in cases

where resins have not been appliedpreviously to the root surface.Consideration must be given to thefuture need for muco-gingival

grafting to the application of anyrestorative material as an uncontami-nated dentine surface is necessaryfor re-attachment.

Sensitivity management

The challenge for sensitivity manage-ment is greatest when the sensitivetooth does not have or require arestoration. Then, the number ofteeth involved and the location andfrequency of the sensitivity dictatethe best type treatment.

Among the reversible treatmentoptions are materials that interfere

with the transmission of the painstimulus at the level of the A-deltafibres around the odontoblast(potassium salts), or exert a block-ing effect on the open dentinetubules (strontium, oxalates or fluo-ride agents). Some protein preci-

pitants may act in a dual capacity.A number of topical agents havebeen used to reduce tooth sensitivity.

The most common for professionalapplication are fluorides. Fluoridemay decrease sensitivity peripher-ally by occluding the dentinetubules through crystallisation andreducing the fluid flow to the pulp13.Patients may use a prescriptiontoothpaste with higher concentra-tions of fluoride (5,000ppm), or

the dentist may apply a topical fluo-ride either as a gel in a tray to treatmany teeth, or as a varnish to treatspecific, accessible areas of a singletooth.

Another group of materials isthe oxalate salts, include potassiumoxalate and ferric oxalate. Thesematerials, which are generallyapplied in a rubbing or burnishingmotion, act by occluding thetubules and reducing tubule fluid

flow in either direction. Otheragents applied by the dental profes-sional are the dentin-bondingderivatives or agents and the

HEMA/gluteraldehyde products,which either occlude the tubules orprecipitate the protein in the tubule.

Desensitising toothpastes

The most common, professionallyendorsed, self-applied approach totreating sensitive teeth is the use ofdesensitising toothpastes14, whichcontain potassium salts (nitrate orchloride). Potassium ions pass easilythrough the enamel and dentine to

the pulp in a matter of minutes

15,16

.Potassium is believed to act byinterfering with the transmission ofthe stimuli by depolarising thenerve surrounding the odontoblastprocess. Most potassium-baseddesensitising toothpastes also containfluoride for cavity protection, andsome offer an array of flavoursand the whitening, tartar-control,and baking soda benefits found inmost regular toothpastes (e.g. the

Sensodyne

range, GlaxoSmithKline,Crest Sensitivity Protection, Proctor& Gamble, or Colgate Sensitive,Colgate Palmolive). Strontium salts(chloride and acetate), that arethought to act by blocking the opendentine tubule, can also stillbe found in desensitising tooth-pastes (Sensodyne Original,GlaxoSmithKline).

In clinical trials, the desensitisingeffect of anti-sensitivity toothpaste

generally takes about two weeksof application twice per day toshow reductions in sensitivity, andgreater effect develops with

continued use17. The patient shouldbe advised in accordance with themanufacturers instructions, typicallyto be applied by brushing twicedaily as part of the regular oralhygiene regimen. Recommendingdesensitising toothpaste that is simi-lar in properties to the patientsregular paste will enhance compli-ance and increase effectiveness.

However, desensitising tooth-pastes have been applied in a varietyof formats. In 1995, Jeromepublished a case study describing atechnique for treating tooth sensi-tivity in post-periodontal surgerypatients18. Instead of having thepatient brush with a dentifricecontaining potassium nitrate, heplaced the desensitising toothpastein a custom-made soft tray (Figure12). By increasing medicament-toothcontact time, the tray deliverysystem increased the efficacy of thepotassium nitrate dentifrice. In

2001, Haywood et alpublished apaper describing the use of 5 percent potassium nitrate in bleachingtrays to reduce the sensitivity thatis triggered during bleaching19.

They determined that 1030minutes of wear time generallyalleviates sensitivity.

The current recommendation inthe USA is to use a desensitisingtoothpaste containing 5 per centpotassium nitrate and fluoride, but

without sodium lauryl sulphate(SLS) if available. SLS is the ingre-dient primarily responsible for thefoaming action. One possible side

Figure 12. Non-scalloped, no reservoir tray used for bleaching


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Figure 13. Examples of various tray designs scalloped, reservoir and non-reservoir

effect of using a large volume oftoothpaste may be occasional tissueirritation, possibly from the one ofthe toothpaste ingredients. If irrita-tion occurs, the patient should try adifferent flavour and composition.

If the gingival problem persists, thedental professional can switch thepatient to a professionally suppliedpotassium nitrate and fluorideproducts specifically designed forat-home, tray delivery application.

The cost of these products isconsiderably more than toothpaste,and the patient must visit thedentist for re-supply. Therefore, ifthe patient can use toothpaste with-out untoward problems, then thepatient has a lifetime approach tocontrolling sensitivity. The patientshould be advised to experiment

with a variety of toothpastes beforecommitting to the professionallysupplied materials.

One of the primary motivationsfor people coming to the dentalpractice is to have their teethcleaned, so that their smile will be

white. However, some people withsensitive teeth avoid hygiene appoint-ments because of the discomfortthe procedure elicits. Such sensitiv-ity can be a pre-existing conditionor a result of the cleaning proce-dure. The tray delivery system maybe beneficial to this routine dentalhygiene patient with a history ofsensitive teeth: applying the desen-sitising toothpaste in a tray for1030 minutes prior to the prophy-laxis appointment has been

reported to reduce discomfortduring and after the procedure.Should discomfort occur after theprocedure, the material can bere-applied as needed until it islessened or gone.

The effect of bleaching

If the patient has previouslybleached their teeth with thenightguard vital bleaching technique(see below), then the custom-fittedtray can be used as the carrier forthe anti-sensitivity toothpaste. If thepatient is not a candidate forbleaching but has a history of

chronic sensitivity, then a non-scal-loped, no-reservoir designed tray canbe fabricated (Figure 13). If it isunclear whether this approach willbenefit the patient, a less involvedtechnique may be tried that uses adirect thermoplastic tray madedirectly in the patients mouth with-out an alginate impression, stonecast and laboratory exercise20,21.

While this tray is more rigid, it is aquick means for determining theefficacy of a tray-applied medica-ment such as toothpaste or fluoridegels22.

Much has been learned abouttooth sensitivity with the advent ofat-home bleaching. Nightguard

vital bleaching applies a 10 per centcarbamide peroxide material in acustom-fitted tray overnight for 26 weeks. Although some claimshave been made for nightguardbleaching products that do notinduce sensitivity, double-blindclinical studies have shown thatsensitivity occurs in 55 per cent to75 per cent of treatment groups2334,

with placebo groups experiencingsensitivity in 20 to 30 per cent ofsubject. One study even reportedtooth sensitivity of about 15 percent in subjects wearing only thebleaching tray. Therefore, it appearsthat this kind of sensitivity is amulti-factorial event that cannot betotally avoided because it is not

exclusively related to the peroxidewhitening material.

One option to address this typeof sensitivity is to try to predict

which patients will become sensi-tive. However, the only significantpredictors determined thus far35 area previous history of sensitive teethand a regimen of more than oneapplication of the bleaching solu-

tion per day. Moreover, the 26month treatment time for thecomplete management of tetracy-cline-stained teeth has demonstratedjust how sporadic the sensitivity isin some patients36.

Since tooth sensitivity duringbleaching is common, yet unpredict-able, it must be addressed clinically

when it occurs. Often the sensitiv-ity experienced is mild, and requiresno alteration in the treatmentprotocol. In cases where it cannotbe ignored, the dentist may have toinstruct the patient to decrease thefrequency (typically, to every otherday) and duration of treatments37.

When this protocol fails, somepractitioners advocate the use oftopical fluorides in conjunction

with the bleaching treatments.Others recommend using a desen-sitising toothpaste for 23 weeksprior to initiating as well as duringbleaching. Persons experiencingnight time sensitivity may switch todaytime wear and reduce contact


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time of the peroxide to 24 hours.In severe cases patients may haveto stop bleaching for a few weeksor even altogether.

The advent of tray delivereddesensitising agents containing

potassium has greatly aided thedentist in taking a more activeapproach to managing sensitivityand affords patients a simple,effective means to control theirtreatment. The bleaching studydemonstrates the efficacy of 1030 minute applications of thedesensitising material, used asneeded (one time only, once a

week, cont inuous before eachbleaching treatment, or alternated

with bleaching treatments).

Conclusion

There are many causes of and treat-ments for tooth sensitivity. Thedentist must explore all possibili-ties, form a definitive diagnosis ordiagnoses, then implement manage-ment strategies that address allcauses and predisposing factors toreduce or eliminate the sensitivity.

Treatments may range from simpletopically applied medicaments athome by the patient to restorations,pulp removal or muco-gingivalsurgery. The severity and extent ofthe sensitivity will dictate variationsin treatment options. Chronicproblems with teeth not havingrestorations or obvious pathologyare most disconcerting. The use ofa desensitising agent such as 5 percent potassium nitrate-fluoride gel(toothpaste) applied in the bleachingtray as needed for tooth sensitivitycan be effective and gives thepatient more control over thecondition. This tray delivery tech-nique reduces tooth sensitivity fromnightguard bleaching in a majorityof patients, which allows mostpatients (including those under-going long-term treatment fortetracycline staining) to continue

whitening to successful completion.

References

1. Meurman J H, Harkonen M, Naveri

H, et al. Experimental sports drinkswith minimal dental erosion effect.

Scand J Dent Res 1990 98: 120128.

2. Harrison J L, Roeder L B. Dental ero-

sion caused by cola beverages. Gen Dent

1991 39: 2324.

3. Grobler S R, Jenkins G N, Kotze D.

The effects of the composit ion and

method of drinking of soft drinks on

plaque pH. Br Dent J 1985 158: 293

296.

4. Rytomaa I, Meurman J H, Koskinen J,

et al. In vitro erosion of bovine enamel

caused by acidic drinks and other

foodstuffs. Scand J Dent Res 1988 96:

324333.

5. Grenby T H, Phillips A, Desai T, et al.

Laboratory studies of the dental prop-

erties of soft drinks. Br J Nutr 1989

62: 451464.

6. Grobler S R, Senekal P J, Laubscher JA. In vitro demineralization of enamelby orange juice, apple juice, Pepsi Cola

and Diet Pepsi Cola. Clin Prev Dent

1990 12: 59.

7. Madison S, Walton R. Cervical root

resorption following bleaching of

endodontically treated teeth. J Endod

1990 16: 570574.

8. Leonard R H Jr , Bentley C D,

Haywood V B. Salivary pH changes

during 10% carbamide peroxide

bleaching. Quint essence Int 1994 25:

547550.

9. Haywood V B. History, safety, and

effectiveness of current bleaching

techniques and applications of the

nightguard vital bleaching technique.

Quintessenc e Int 1992 23: 471488.

10 . Cooper J S, Bokmeyer T J, Bowles WH. Penetration of the pulp chamber

by carbamide peroxide bleaching

agents. J Endod 1992 18: 315317.11 . Schulte J R, Morrissette D B, Gasior

E J, et al. The effects of bleaching

application time on the dental pulp. J

Am Dent Asso c 1994 125: 13301335.

12 . Heymann H O: Tooth Sensitivity:Causes, Prevention and Treatment.

Internet audio/slide lecture. DenTrek.

com

13 . Gaffar A. Treating hypersensitivity

with fluoride varn ishes. Compend

Contin Educ Dent1998 19: 10881090,

1092, 1094, pas sim.

14 . Report of a global survey of 11000

adults about sensitive teeth. Research

Quorum, Basingstoke, Hampshire,

UK, 2002.

15 . Hodosh M. A superior desensitizer

potassium nitrate. J Am Dent Assoc

1974 88: 831832.

16. Markowitz K. Tooth sensitivity:

mechanisms and management. Compen-

dium 1993 14: 10321046.

17 . Silverman G, Berman E, Hanna C B,et al. Assessing the efficacy of three

dentifrices in the treatment of Den-

tine hypersensitivity. J Am Dent Assoc

1996 127: 191201.

18 . Jerome C E. Acute care for unusual

cases for Dentine hypersensitivity.

Quintessence Int 1995 26: 715716.

19 . Haywood V B, Caughman W F, Frazier

K B, et al. Tray delivery of potassium

nitrate-fluoride to reduce bleaching

sensitivity. Quinte ssence Int 2001 32:

105109.

20 . Haywood V B, Caughman W F, Frazier

K B, et al. Feasibility of immediate

direct thermoplastic whitening trays.

J Dent Res 1998 77: 273.

21 . Haywood V B. Immediate fabrica-

tion of direct thermoplastic whiteningtrays. Internet audio/slide lecture.

DenTrek.com22 . Haywood V B, Caughman W F, Frazier

K B, et al. Fabrication of immediate

thermoplastic whitening trays. Contem-

pora ry Estheti cs and Rest orat ive Prac tice

2001 5: 84-86.

23 . Barnes D M, Kihn P W, Romberg E,

et al. Clinical evaluation of a new 10%

carbamide peroxide tooth-whitening

agent. Compend Contin Educ Dent1998

19: 968978.

24 . Heymann H O, Swift E J Jr, Bayne S

C, et al. Clinical evaluation of two

carbamide peroxide tooth-whitening

agents. Compend Cont Educ Dent 1998

19: 359376.

25 . Reinhardt J W, Eivins S E, Swift E J

Jr, et al. A clinical study of nightguard

vita l bleaching. Quintessence Int 1993

24: 379384.26 . Swift E J Jr, May K N, Wilder A D,

et al. Six-month clinical evaluation of

a tooth whitening system using an in-novative experimental design. J Esthet

Dent 1997 9: 265274.

27 . Haywood V B, Leonard R H, Nelson

C F, et al. Effectiveness, side effects

and long-term status of nightguardvita l bleaching. J Am Dent Assoc1994

125: 12191226.

28 . Leonard R H Jr. Efficacy, longevity,

side effects, and patient perceptions

of nightguard vital bleaching. Compend

Cont Educ Dent 1998 19: 766770,

772, 774, pas sim.

29 . Leonard R H, Bentley C, Phillips C,et

al. ADA Controlled clinica l tria l of a

10% carbamide peroxide solution. J

Dent Res 1997 76: 309.

30 . Leonard R H, Garland G E, Eagle J C,

et al. Safety issues of 10% and 16%carbamide peroxide whitening solu-

tions. J Dent Res 1999 78: 145.

31 . Howard W R. Patient-applied toothwhiteners. J Am Dent Asso c1992 123:


9/9

5760.32 . Rosenstiel S F, Gegauff A G, Johnston

W M. Randomized clin ical tria l of the

efficacy and safety of a home bleach-

ing procedure. Quinte sse nce Int 1996

27: 413424.

33 . Small B W. Bleaching with 10 percent

carbamide peroxide: an 18-month

study. Gen Dent 1994 42: 142146;

quiz 153154.

34 . Matis B A, Cochran M A, Eckert G, et

al. The efficacy and safety of a 10%

carbamide peroxide bleaching gel.

Quintessence Int 1998 29: 555563.

35 . Leonard R H, Haywood V B, Phillips

C. Risk factors for developing tooth

sensitivity and gingival irritation asso-

ciated with nightguard vital bleach-

ing.Quintess ence Int 1997 28: 527534.

36. Haywood V B, Leonard R H,

Dickinson G L. Efficacy of six months

of nightguard vital bleaching of tetra-

cycline-stained teeth. J Esthet Dent

1997 9: 1319.

37 . Haywood V B. Current status and

recommendations for dentist-pre-

scribed, at-home tooth whitening.Contemporary Esthetics and Restorative

Practice 1999 3: 29.

2002 dentine hypersensitivity bleaching and restorative considerations for successful management

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