An impacted maxillary canine is usu-ally diagnosed during a routine den-tal examination. Disturbance in theeruption of permanent maxillary caninescan cause problems in the dental arch andadjacent teeth, which require special careand attention. There fore, clinicians shouldbe capable of dealing with this clinical situ-ation in order to deliver optimal treatment.

Clinicians have various definitions ofimpaction. Canine impaction can bedefined as an unerupted tooth after its rootdevelopment is complete; or a tooth stillunerupted when the corresponding toothon the other side of the arch has been erupt-ed for at least 6 months and has a completeroot formation; or a condition in which atooth is embedded in the alveolus and islocked in by bone, adjacent teeth, or otherobstacles and cannot properly erupt intothe oral cavity.1-5 This includes teeth inwhich eruption is significantly delayed andthere is no clinical or radiographic evidencethat further eruption is likely to happen.1-5

Maxillary canines are among the lastteeth to develop and have the longest peri-od of development. They also have thelongest and most devious path of eruptionfrom the formation point lateral of the pisi-form fossa to the final position in the dentalarch.1-5 Therefore, there is an increasedpotential for mechanical disturbancesresulting in displacement and impaction.

This article discusses the etiology, diag-nosis, and clinical management of impact-ed maxillary canine teeth.

PREVALENCE AND ETIOLOGYPermanent maxillary canine impaction hasbeen reported in about 1% to 2% of the pop-ulation.1-5 This makes the maxillary canine

the second most commonly impacted tooth,after third molars.1-7 Research indicates thatwomen are twice as likely as men to haveimpacted maxillary canines.1-11 The preva-lence of impacted maxillary canines isbetween 0.9% and 2%.1-5,11-13 It has beenfound that maxillary impacted caninesoccur palatally 85% of the time while only15% of impactions occur labially.1-5,14According to Al-Nimri and Gharaibeh,15palatal canine impaction occurred most fre-quently in subjects with a Class II division 2malocclusion. Among all patients withimpacted canines, it was found that unilat-eral impaction is much more common than

bilateral impaction.1-5,16 Maxillary canineimpactions appear to be 10 to 20 times morefrequent than those in the mandible.1-5,17

While the etiology of impacted maxil-lary canines is thought to be multifactori-al, they are not likely to originate frommodified conditions in modern civiliza-tion such as food texture or eating behav-ior;18 however, the exact etiology is stillunclear.5,11 Possible causes for impactedcanines may include one or more of the fol-lowing local factors: inadequate space foreruption or early loss of primary canines;abnormal position of the tooth bud; the

62

DENTALCETODAY.COM SEPTEMBER 2012

Jae Hyun Park,DMD, MSD,MS, PhD

ThianSrisurapol,DDS

Kiyoshi Tai,DDS, PhD

Impacted Maxillary Canines:Diagnosis and Management

continued on page 64

Figures 1a to 1f. Pretreatment intraoral photographs and a panoramic radiograph showing the impactedmaxillary right canine.

ORTHODONTICScecedentalCEtoday.comTest 153

a b

c d

e f

Maxillary canines are among thelast teeth to develop and have thelongest period of development.

presence of an alveolar cleft, a cysticlesion or neoplasm; ankylosis; dilac-erations of the root; an iatrogenic ori-gin; and an idiopathic condition forno apparent reason.1-5 Systemic con-ditions such as endocrine deficien-cies, malnutrition, febrile disease, orirradiation can also account forimpacted canines.1-5Currently, there are 2 major theo-

ries that have been used to explain thecause of maxillary canine impaction:the guidance theory and the genetictheory. The guidance theory statesthat excess space in the canine area ofthe dental arch during developmentand eruption owing to an absent ormalformed lateral incisor root causesthe canine to lose its way and eruptimproperly, because a permanentcanine tooth needs the distal aspect ofa lateral incisors root to guide itdownward to the occlusion.19-22 Thegenetic theory claims that palatallyimpacted canines are the result of acombination of multiple gene expres-sions which cause dental anomaliessuch as congenital missing or peg-shaped lateral incisors due to a devel-opmental disturbance of the dentallamina.23-25

CLINICAL DIAGNOSISImpacted canine teeth can be detectedas early as age 8 years.13,26 Clinicalexamination includes overall archinspection, palpation of canine bulges,mobility of primary canines, and areview of the patients chronologicalage and history of eruption/exfoliationpatterns of the dentition. Cliniciansshould be aware that there is a possi-bility of canine impaction in theabsence of canine bulges, abnormalityin shape, missing lateral incisors, orless mobility of primary canines.Unusual movement of lateral or cen-tral incisors can also be a sign of rootresorption due to pressure from mal-posed canines. When there is the clini-cal presence of any of these signs, radi-ographic examination should be per-formed to confirm the diagnosis.1-5

RADIOGRAPHIC DIAGNOSISRadiographic examination should beinitiated with routine periapical radi-

ographs. However, when clinical signslead to a possibility of canine im -paction, radiographic evaluation isimmediately needed to confirm thediagnosis and assist in developing anappropriate treatment plan. There arevarious radiographic methods that canbe used to obtain needed information.Periapical radiographs can be

help ful by using at least 2 radiographsat different angles to determine thebuccolingual position of a particulartooth. There are 2 methods that arewidely used: Clarks rule and the buc-cal object rule. Both use the differentangulation of the x-ray beam to locateobjects in different directions. Thesemethods, also known as same lingual-opposite-buccal rule, will make theob jects on the lingual side move to the

same direction as the x-ray tube andobjects on the buccal side move in theopposite direction.2,27Panoramic radiographs are also

widely used to locate the position ofimpacted canines. They are part of thefundamental imaging taken for dentalrecords and treatment planning. Theyprovide an overall look of the entiredentition including the temporo-mandibular joints (TMJs). Many predic-tion values proposed in the literaturecome from this type of radiograph.Occlusal radiographs can identify

the position of impacted maxillarycanines accurately in conjunctionwith routine periapical radiographs.When properly obtained, they pro-vide information about the buccolin-gual direction of the crown and rootof the canine. They also provide infor-mation related to the distance be -tween the midline and the position ofthe canines. The disadvantage of thisradiograph is that it cannot provide

any information about the verticalposition of the canines.Lateral cephalometric radio graphs

can help determine the position ofimpacted canines relative to other struc-tures. They are helpful because they aresome of the fundamental radiographsthat all patients have taken prior to thebeginning of orthodontic treatment.Maxillary canines can be located easilyon this radiograph as early as age 8 or 9years. Their inclination should be par-allel to the maxillary incisors.5Posterior-anterior radiographs are

also useful. Normal canines in this typeof radiograph should angle medially,and crowns should be lower than theapex of the lateral incisors and the later-al border of the nasal cavity.8 However,this method still provides only 2-dimen-sional images with some degree ofsuperimposition. Nevertheless, thistype of radiograph is not usually takenunless there are skeletal asymmetry

and/or transverse width issues. If thereis any concern of impaction with otheranomalies, it might be better to utilizecone beam computed tomography(CBCT) instead.CBCT has the great advantage of

showing hard-tissue reconstruction inthe area of interest in 3 dimensions,presenting a view without any super-imposition,28 and also providing a 1:1magnification which can be used toreproduce panoramic or cephalomet-ric images.6 Its use in orthodonticsincludes impacted teeth and TMJ eval-uations, 3-dimensional views of upperairways, assessment of maxillofacialgrowth, and development and dentalage estimation.29 CBCT scans are farbetter than conventional panoramicradiographs in verifying the orienta-tion and location of the impactedcanine and its relationship to neigh-boring structures.6,30,31 This tech-nique makes identification of the

ORTHODONTICS64

DENTALCETODAY.COM SEPTEMBER 2012

Impacted Maxillary Canines...continued from page 62

Figures 2a to 2c. Pretreatment 3-dimensional volume rendering showing the location of the impacted maxillary right canine. The crown waslocated palatally and the root was located buccally.

Figures 3a to 3f. Intraoral treatment progress views and a panoramic radiograph.

a b

c d

e f

a b c

Lateral cephalometric radiographs can help determine the position of impacted canines relative to other structures.

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SEPTEMBER 2012 DENTALCETODAY.COM

ORTHODONTICS 65

Figures 4a to 4f. Posttreatment intraoral photographs and a panoramic radiograph.

a b

c d

e f

exact position and shape of impactedcanines possible, which is crucial intreatment planning. Furthermore, it isvery helpful in evaluating damage toadjacent teeth and the amount of sur-rounding bone.32 The major disadvan-tage of CBCT is the increased amountof radiation exposure, which is at least4 times higher than with ordinarypanoramic radiograms.6,29,33,34 There -fore, orthodontists should considercost-benefit outcomes before orderingthis radiograph.

PREDICTION OF MAXILLARYIMPACTION

There are many predictive values andmeasurements proposed in the litera-ture to help determine the chance of aneventual impacted canine. Ericson andKurol35 proposed predicting canineimpaction using the angulation, dis-tance, and sector of the canines from apanoramic radiograph to determine thechance of an impacted canine. That is,the deeper the cusp tip from the occlusalplane, the more perpendicular to themidline, and the closer to the midline,the greater the chance that tooth im -paction will occur and the longer theduration of treatment.36 Many studieshave shown that the mesiodistal posi-tion gives the best prediction value,while angulation and vertical positionshowed no statistical significance.8,37-40Furthermore, an impacted caninewhich is closer to the midline, or whose

cusp tip is mesial to the midline of thelateral incisor, is more likely to bepalatally impacted, and root resorptionsare also more frequent.41

MANAGEMENT OF CANINE IMPACTION

Maxillary canine impaction usuallyneeds multidisciplinary care, whichinvolves oral surgery and periodonticsalong with orthodontic treatment. It isessential that the various cliniciansworking on the case have good com-munication to provide optimal care forthe patient.2 The management ofimpacted canines can be divided into 2treatment categories: interceptivetreatment and corrective treatment.

Interceptive TreatmentPreventive modalities should be per-formed in cases that have a strong pos-sibility of canine impaction. The elimi-nation of obstacles to the path of erup-tion and the provision of sufficientroom for underlying canines are essen-tial. Therefore, extraction of the pri-mary canine is thought to be a properinterceptive treatment. Many claimthat this is the best treatment and itprovides the most stable results.1-5When appropriate, interceptive treat-ment is the most advantageous interms of cost-benefit as compared toother more aggressive methods.11

However, there are many factorsto be considered before interceptive

treatment can be done. A classic studyfrom Ericson and Kurol35 showed thatextraction of the primary caninesbetween the ages of 10 and 13 yearswill obtain a favorable result withmost palatally erupted canines. If thecusp tip of a permanent maxillarycanine in the panoramic radiographdoes not exceed the midline of the lat-eral incisor, the chance of the canineerupting normally is 91%; if the cusptip does exceed the midline of the lat-eral incisor, the chance for normallyerupting drops to 64%.35

Many modifications have beenadded to the extraction of primarycanines to improve the results, includ-ing the use of cervical pull headgear,42double extraction of the primary ca -nine and the primary first molar,43,44

the use of a transpalatal arch (TPA),45and the use of a rapid maxillary expan-sion in combination with a TPA.46 Allof these show favorable results as com-pared to the extraction of primarycanines alone. The selection of thesemodifications should be based on indi-vidual clinical presentations.

Corrective TreatmentCorrective treatment is performed in

situations where orthodontists can-not render preventive or interceptivetreatment for some reason, or patientspresent beyond the point of preven-tion. There should be an attempt tobring impacted maxillary caninesdown to occlusion if possible, becausepermanent canines are important forboth functional and aesthetic reasons.Treatment can be divided into 2 types,labial or palatal, depending on theposition of the ectopic canines.

Three techniques have been pro-posed by Kokich47 for uncovering alabially unerupted maxillary canine(gingivectomy, apically positionedflap, and closed eruption technique).He also suggested that orthodontistsshould evaluate 4 criteria to deter-mine the correct method for uncover-

ing the tooth so the outcome achievesthe optimum periodontal health.47These criteria include the distancebetween the canine cusp and themucogingival junction; the labiolin-gual position; the mesiodistal posi-tion; and the amount of gingiva in thearea of the impacted canine.

In palatally impacted canines, theconcern about the lack of keratinizedgingiva disappears because palatal tis-

The management of impacted canines can be divided into 2 treatment categories....

Figures 5a to 5f. Postretention intraoral photographs and a panoramic radiograph after 2 years.

a b

c d

e f

sue is a dense connective tissue.Bishara2 suggested 2 surgical methodsfor exposing the impacted canines: sur-gical exposure followed by allowingspontaneous eruption; and surgicalexposure with auxiliary attachmentfor further orthodontic treatment.

The first method is useful whenthe canine has a correct axial inclina-tion and needs no upright correctionduring its eruption, but this methodmay increase treatment time and beunable to control the path of erup-tion.2 Kokich47 suggested performingthis method before the beginning oforthodontic treatment or during thelate mixed dentition because thetooth will erupt in a more favorable

location, which will facilitate ortho-dontic movement without draggingthe crown through the palatal gingi-va. Schmidt and Kokich48 also report-ed that this technique had minimaleffects on the periodontium and thatthe overall effects on the impactedcanine appeared better than thosefrom the closed exposure and earlytraction techniques.

The second method is used whenthere is no eruption force left or thetooth does not lie in a favorable direc-tion and orthodontic force is requiredto move the impacted tooth awayfrom the roots of the adjacent teethand bring it to the proper position.After sufficient space has been creat-ed, surgical exposure is performedand the attachment is placed. Lightorthodontic force (not to exceed 60 gor 2 oz) is then applied to move thetooth to the desired position by vari-ous orthodontic techniques (Figures1a to 5f).2,5

Removal of an impacted canine isone approach that is rarely used butmight need to be considered if theimpacted canine is ankylosed, hasinternal or external root resorption,severe dilaceration, or the position isundesirable and it is impossible tobring it to the occlusion.2,5 Wriedt etal30 suggested that if the inclination ofimpacted canines in panoramic radi-ographs is more than 45, they willmore likely require surgical removal.If this is the final decision, the ortho-

dontist must consider alternativetreatments to substitute for the miss-ing canine. The options can be premo-lar substitution, autotransplantation,or prosthetic substitution by workingtogether with other specialties. Thepatient should be informed of all thesetreatment outcome possibilities be -fore beginning the treatment.5

SUMMARY Canine impaction is a relatively fre-quent clinical presentation in den-tistry, with challenges that should beresolved. A good understanding by theclinician of the situation and treat-ment options can have a significantimpact on the treatment outcome.Therefore, clinicians should be compe-tent to perform the proper investiga-tion, provide a correct diagnosis, devel-op an optimum treatment plan, andrender appropriate treatment for eachindividual patient so each patient real-izes the best outcome possible.

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crepancies and potentially impacted maxillary

canines in mixed-dentition patients. Angle Orthod.2007;77:430-435.

2. Bishara SE. Impacted maxillary canines: a review.

Am J Orthod Dentofacial Orthop. 1992;101:159-171.

3. Shapira Y, Kuftinec MM. Early diagnosis and inter-

ception of potential maxillary canine impaction. JAm Dent Assoc. 1998;129:1450-1454.

4. Ngan P, Hornbrook R, Weaver B. Early timely man-

agement of ectopically erupting maxillary canines.

Semin Orthod. 2005;11:152-163. 5. Bedoya MM, Park JH. A review of the diagnosis and

management of impacted maxillary canines. J AmDent Assoc. 2009;140:1485-1493.

6. Jacobs R. Dental cone beam CT and its justified

use in oral health care. JBR-BTR. 2011;94:254-265.

7. Litsas G, Acar A. A review of early displaced maxil-

lary canines: etiology, diagnosis and interceptive

treatment. Open Dent J. 2011;5:39-47. 8. Sambataro S, Baccetti T, Franchi L, et al. Early pre-

dictive variables for upper canine impaction as

derived from posteroanterior cephalograms. AngleOrthod. 2005;75:28-34.

9. Cooke J, Wang HL. Canine impactions: incidence

and management. Int J Periodontics RestorativeDent. 2006;26:483-491.

10. Proffit WR, Fields HW, Sarver DM. ContemporaryOrthodontics. 4th ed. St. Louis, MO: MosbyElsevier; 2007.

11. McSherry PF. The ectopic maxillary canine: a

review. Br J Orthod. 1998;25:209-216. 12. Thilander B, Jakobsson SO. Local factors in

impaction of maxillary canines. Acta OdontolScand. 1968;26:145-168.

13. Ericson S, Kurol J. Radiographic assessment of

maxillary canine eruption in children with clinical

signs of eruption disturbance. Eur J Orthod.1986;8:133-140.

14. Ericson S, Kurol J. Radiographic examination of

ectopically erupting maxillary canines. Am J OrthodDentofacial Orthop. 1987;91:483-492.

15. Al-Nimri K, Gharaibeh T. Space conditions and den-

tal and occlusal features in patients with palatally

impacted maxillary canines: an aetiological study.

Eur J Orthod. 2005;27:461-465. 16. Peck S, Peck L, Kataja M. Site-specificity of tooth

agenesis in subjects with maxillary canine malposi-

tions. Angle Orthod. 1996;66:473-476. 17. Rebellato J, Schabel B. Treatment of a patient with

an impacted transmigrant mandibular canine and

a palatally impacted maxillary canine. AngleOrthod. 2003;73:328-336.

18. Rajic S, Muretic Z, Percac S. Impacted canine in a

prehistoric skull. Angle Orthod. 1996;66:477-480. 19. Jacoby H. The etiology of maxillary canine

impactions. Am J Orthod. 1983;84:125-132. 20. Brin I, Becker A, Shalhav M. Position of the maxil-

lary permanent canine in relation to anomalous or

missing lateral incisors: a population study. Eur JOrthod. 1986;8:12-16.

21. Becker A, Zilberman Y, Tsur B. Root length of later-

al incisors adjacent to palatally-displaced maxillary

cuspids. Angle Orthod. 1984;54:218-225. 22. Miller B. The influence of congenitally missing

teeth on the eruption of the upper canine. DentPract Dent Rec. 1963;13:497-504.

23. Pirinen S, Arte S, Apajalahti S. Palatal displace-

ment of canine is genetic and related to congenital

absence of teeth. J Dent Res. 1996;75:1742-1746. 24. Peck S, Peck L, Kataja M. Concomitant occurrence

of canine malposition and tooth agenesis: evi-

dence of orofacial genetic fields. Am J OrthodDentofacial Orthop. 2002;122:657-660.

25. Frazier-Bowers SA, Puranik CP, Mahaney MC. The

etiology of eruption disordersfurther evidence of

a genetic paradigm. Semin Orthod. 2010;16:180-185.

26. Ericson S, Kurol J. Longitudinal study and analysis

of clinical supervision of maxillary canine eruption.

Community Dent Oral Epidemiol. 1986;14:172-176.

27. Jacobs SG. Radiographic localization of unerupted

maxillary anterior teeth using the vertical tube shift

technique: the history and application of the

method with some case reports. Am J OrthodDentofacial Orthop. 1999;116:415-423.

28. Kaeppler G. Applications of cone beam computed

tomography in dental and oral medicine. Int JComput Dent. 2010;13:203-219.

29. Smith BR, Park JH, Cederberg RA. An evaluation of

cone-beam computed tomography use in postgrad-

uate orthodontic programs in the United States

and Canada. J Dent Educ. 2011;75:98-106. 30. Wriedt S, Jaklin J, Al-Nawas B, et al. Impacted

upper canines: examination and treatment propos-

al based on 3D versus 2D diagnosis. J OrofacOrthop. 2012;73:28-40.

31. Walker L, Enciso R, Mah J. Three-dimensional local-

ization of maxillary canines with cone-beam com-

puted tomography. Am J Orthod DentofacialOrthop. 2005;128:418-423.

32. Ericson S, Kurol J. Resorption of incisors after

ectopic eruption of maxillary canines: a CT study.

Angle Orthod. 2000;70:415-423. 33. Batista WO, Navarro MV, Maia AF. Effective doses in

panoramic images from conventional and CBCT

equipment. Radiat Prot Dosimetry. 2012;151:67-75. Epub 2011 Dec 14.

34. Tymofiyeva O, Rottner K, Jakob PM, et al. Three-

dimensional localization of impacted teeth using

magnetic resonance imaging. Clin Oral Investig.2010;14:169-176.

35. Ericson S, Kurol J. Early treatment of palatally

erupting maxillary canines by extraction of the pri-

mary canines. Eur J Orthod. 1988;10:283-295. 36. Crescini A, Nieri M, Buti J, et al. Orthodontic and

periodontal outcomes of treated impacted maxil-

lary canines. Angle Orthod. 2007;77:571-577. 37. Lindauer SJ, Rubenstein LK, Hang WM, et al.

Canine impaction identified early with panoramic

radiographs. J Am Dent Assoc. 1992;123:91-92,95-97.

38. Warford JH Jr, Grandhi RK, Tira DE. Prediction of

maxillary canine impaction using sectors and angu-

lar measurement. Am J Orthod DentofacialOrthop. 2003;124:651-655.

39. Fleming PS, Scott P, Heidari N, et al. Influence of

radiographic position of ectopic canines on the

duration of orthodontic treatment. Angle Orthod.2009;79:442-446.

40. Olive RJ. Factors influencing the non-surgical erup-

tion of palatally impacted canines. Aust Orthod J.2005;21:95-101.

41. Jung Y, Liang H, Benson B, et al. The assessment of

impacted maxillary canine position with panoramic

radiography and cone beam computed tomogra-

phy. Dentomaxillofac Radiol. 2012;41:356-360.Epub 2011 Nov 24.

42. Leonardi M, Armi P, Franchi L, et al. Two intercep-

tive approaches to palatally displaced canines: a

prospective longitudinal study. Angle Orthod.2004;74:581-586.

43. Alessandri Bonetti G, Incerti Parenti S, Zanarini M,

et al. Double vs single primary teeth extraction

approach as prevention of permanent maxillary

canines ectopic eruption. Pediatr Dent.2010;32:407-412.

44. Alessandri Bonetti G, Zanarini M, Incerti Parenti S,

et al. Preventive treatment of ectopically erupting

maxillary permanent canines by extraction of

deciduous canines and first molars: A randomized

clinical trial. Am J Orthod Dentofacial Orthop.2011;139:316-323.

45. Baccetti T, Sigler LM, McNamara JA Jr. An RCT on

treatment of palatally displaced canines with RME

and/or a transpalatal arch. Eur J Orthod.2011;33:601-607.

46. Sigler LM, Baccetti T, McNamara JA Jr. Effect of

rapid maxillary expansion and transpalatal arch

treatment associated with deciduous canine

extraction on the eruption of palatally displaced

canines: A 2-center prospective study. Am J OrthodDentofacial Orthop. 2011;139:e235-e244.

47. Kokich VG. Surgical and orthodontic management

of impacted maxillary canines. Am J OrthodDentofacial Orthop. 2004;126:278-283.

48. Schmidt AD, Kokich VG. Periodontal response to

early uncovering, autonomous eruption, and ortho-

dontic alignment of palatally impacted maxillary

canines. Am J Orthod Dentofacial Orthop.2007;131:449-455.

Dr. Park is an associate professor and chair ofthe postgraduate orthodontic program at the

Arizona School of Dentistry and Oral Health, A. T.

Still University, Mesa, Ariz. He serves as an asso-

ciate editor of the Journal of Clinical PediatricDentistry and as a consulting editor of theInternational Journal of Orthodontics. He is areviewer for 11 dental and orthodontic journals

including the Journal of Dental Research andthe Journal of the American Dental Association.He received the Joseph E. Johnson Clinical

Award at the American Association of

Orthodontists (AAO) Table Clinic Competition

during the 2011 AAO Annual Session. The AAO

appointed him to be the recipient of the AAO

Academy of Academic Leadership Sponsorship

Program Award for 2010. While at New York

University College of Dentistry (NYUCD), he

received the Deans Award, the first place

Master of Science Resident Research Award,

and the first place Post Graduate Resident

Research Award. He was also selected to be the

NYUCD orthodontic resident representative in

the orthodontic resident scholars program dur-

ing the 2006 AAO Annual Session where he won

first place. In addition, Dr. Park was recently

appointed to be the sole editor of a new, upcom-

ing book to be published by NOVA, ComputedTomography: New Research.He can be reachedvia e-mail at jpark@atsu.edu.

Dr. Srisurapol is an international orthodonticresident, postgraduate orthodontic program,

Arizona School of Dentistry and Oral Health, A. T.

Still University, Mesa, Ariz. He graduated from

the Faculty of Dentistry, Khon Kaen University in

Thailand with first class honors. He is also a

dental practitioner at Patong Public Hospital in

Phuket, Thailand. He can be reached at

tsrisurapol@atsu.edu.

Dr. Tai graduated from the Dental School ofTokushima University in Japan. He is a visiting

adjunct assistant professor, postgraduate ortho-

dontic program, Arizona School of Dentistry and

Oral Health, A. T. Still University, Mesa, Ariz. He

is also adjunct faculty at the Graduate School of

Dentistry at Kyung Hee University in Seoul,

Korea. He recently received his PhD from

Okayama Department of Oral and Maxillofacial

Reconstructive Surgery, Okayama University

Graduate School of Medicine, Dentistry and

Pharmaceutical Sciences, in Japan. He has sev-

eral thriving orthodontic practices in Japan and

has lectured internationally on orthodontics. He

can be reached at ktai@tai-ortho.com.

Disclosure: The authors report no disclosures.

ORTHODONTICS66

DENTALCETODAY.COM SEPTEMBER 2012

A good understanding by theclinician of the situation andtreatment options can have asignificant impact....

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The following 16 questions were derived from the article Impacted Maxillary Canines: Diagnosis and Management by Jae Hyun Park, DMD, MSD, MS, PhD et al on pages 62 to 66.

Learning Objectives After reading this article, the individual will learn: l Basic concepts of impacted maxillary canines and evaluations of potentially impacted canines in individuals.l How to make treatment decisions for impacted maxillary canines in various clinical scenarios and time points.

1. Which tooth has the longest and most tortuous eruption path in the mouth?a. Mandibular third molar.

b. Maxillary canine.

c. Maxillary first premolar.

d. Maxillary second premolar.

2. Which tooth is the most frequently impacted in the oral cavity?a. Maxillary canine.

b. Mandibular second premolar.

c. Maxillary lateral incisor.

d. Mandibular third molar.

3. Which criterion (criteria) is (are) used to determine the proper access foruncovering impacted maxillary canines?

a. The distance between the canine cusp and the mucogingival junction.

b. The labiolingual position of the canine cusp.

c. The mesiodistal position of the canine cusp.

d. All of the above.

4. Which one of the following is NOT considered a local etiological factor ofimpacted canines?

a. Vitamin D deficiency.

b. Dentigerous cyst.

c. Cleft palate.

d. Missing permanent maxillary lateral incisors.

5. Which of the following is (are) clinical sign(s) of impacted maxillary canines?a. Absence of a labial bulge.

b. Peg shaped lateral incisor.

c. Retained primary canine.

d. All of the above.

6. When moving the x-ray tube in a mesial direction to localize the palatallyimpacted maxillary canine:

a. The tooth moves mesially.

b. The tooth moves distally.

c. There is no change.

d. None of the above.

7. Which radiographic method is the best to locate the position of impacted maxillary canines?

a. Periapical radiograph.

b. Lateral cephalogram.

c. Panoramic radiograph.

d. Cone beam computed tomography (CBCT).

8. What is the advantage of CBCT?a. Gives a 3-dimensional view.

b. Free of superimposition.

c. 1:1 magnification.

d. All of the above.

9. To predict impacted maxillary canines, which of the following could be used?a. Canine angulation.

b. Vertical distance of canine cusp from occlusal plane.

c. Mesiodistal position of the canine cusp.

d. All of the above.

10. One of the most negative consequences of impacted canines is:a. Decreased arch length.

b. Transposition of adjacent teeth.

c. Increased risk of cystic formation.

d. Causes root resorption of adjacent teeth.

11. Which of the following is the interceptive treatment modality for impactedmaxillary canines?

a. Extraction of primary canine.

b. Extraction of primary canine in combination with cervical pull headgear.

c. Extraction of primary canine in combination with transpalatal arch.

d. All of the above.

12. According to the study from Ericson and Kurol, with extraction of the primarycanine at age 11 years when the cusp tip of the permanent maxillary canineis between the central and the lateral incisors, the chance that this caninewill erupt normally is:

a. 91%.

b. 75%.

c. 64%.

d. 50%.

13. Which of the following is NOT a surgical exposure technique for labiallyimpacted canines?

a. Gingivectomy.

b. Coronally positioned flap.

c. Closed eruption technique.

d. Apically positioned flap.

14. Which surgical technique is NOT performed in the case of a palatally impactedcanine?

a. Open eruption.

b. Close flap with auxiliary attachment.

c. Apically positioned flap.

d. None of the above.

15. The appropriate amount of force used to orthodontically move an impactedcanine is:

a. 30 g.

b. 45 g.

c. 60 g.

d. 90 g.

16. When an impacted canine has to be removed, which of the following is arestorative treatment option?

a. Tooth autotransplantation.

b. Premolar substitution.

c. Prosthetic substitution.

d. All of the above.

Test 153 Expiration date of this CE article is September 1, 2015.cece

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Test 153

Course objectives were achieved. ________

Content was useful and benefited your clinical practice. ________

Review questions were clear and relevant to the editorial. ________

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Written presentation was informative and concise. ________

How much time did you spend reading the article

and completing the test? ________

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Test 153for Impacted Maxillary Canines: Diagnosis and Management

beginning on page 62.

9. a b c d

10. a b c d

11. a b c d

12. a b c d

13. a b c d

14. a b c d

15. a b c d

16. a b c d

1. a b c d

2. a b c d

3. a b c d

4. a b c d

5. a b c d

6. a b c d

7. a b c d

8. a b c d

Please circle your answers below.

ANSWERSHEETcece

SEPTEMBER 2012 DENTALCETODAY.COM

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