impacted maxillary canines: diagnosis and management · chair of the postgraduate orthodontic ......

Continuing Education

Impacted Maxillary Canines:Diagnosis and ManagementAuthored by Jae Hyun Park, DMD, MSD, MS, PhD; Thian Srisurapol, DDS;

and Kiyoshi Tai, DDS, PhD

Course Number: 153

Upon successful completion of this CE activity 2 CE credit hours may be awarded

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LEARNING OBJECTIVESAfter participating in this CE activity, the individual will learn: • Basic concepts of impacted maxillary canines andevaluations of potentially impacted canines in individuals.

• How to make treatment decisions for impacted maxillarycanines in various clinical scenarios and time points.

ABOUT THE AUTHORSDr. Park is an associate professor andchair of the postgraduate orthodonticprogram at the Arizona School ofDentistry and Oral Health, A. T. StillUniversity, Mesa, Ariz. He serves as anassociate editor of the Journal of Clinical

Pediatric Dentistry and as a consulting editor of theInternational Journal of Orthodontics. He is a reviewer for 11dental and orthodontic journals including the Journal ofDental Research and the Journal of the American DentalAssociation. He received the Joseph E. Johnson ClinicalAward at the American Association of Orthodontists (AAO)Table Clinic Competition during the 2011 AAO AnnualSession. The AAO appointed him to be the recipient of theAAO Academy of Academic Leadership SponsorshipProgram Award for 2010. While at New York UniversityCollege of Dentistry (NYUCD), he received the Dean’sAward, the first place Master of Science Resident ResearchAward, and the first place Post Graduate Resident ResearchAward. He was also selected to be the NYUCD orthodonticresident representative in the orthodontic resident scholarsprogram during the 2006 AAO Annual Session where he wonfirst place. In addition, Dr. Park was recently appointed to bethe sole editor of a new, upcoming book to be published byNOVA, Computed Tomography: New Research. He can bereached via e-mail at [email protected].

Disclosure: Dr. Park reports no disclosures.

Dr. Srisurapol is an internationalorthodontic resident, postgraduateorthodontic program, Arizona School ofDentistry and Oral Health, A. T. StillUniversity, Mesa, Ariz. He graduatedfrom the Faculty of Dentistry, Khon Kaen

University in Thailand with first class honors. He is also adental practitioner at Patong Public Hospital in Phuket,Thailand. He can be reached at [email protected].

Disclosure: Dr. Srisurapol reports no disclosures.

Dr. Tai graduated from the Dental Schoolof Tokushima University in Japan. He is avisiting adjunct assistant professor,postgraduate orthodontic program,Arizona School of Dentistry and OralHealth, A. T. Still University, Mesa, Ariz.

He is also adjunct faculty at the Graduate School ofDentistry at Kyung Hee University in Seoul, Korea. Herecently received his PhD from Okayama Department ofOral and Maxillofacial Reconstructive Surgery, OkayamaUniversity Graduate School of Medicine, Dentistry andPharmaceutical Sciences, in Japan. He has several thrivingorthodontic practices in Japan and has lecturedinternationally on orthodontics. He can be reached [email protected].

Disclosure: Dr. Tai reports no disclosures.

INTRODUCTIONAn impacted maxillary canine is usually diagnosed during aroutine dental examination. Disturbance in the eruption ofpermanent maxillary canines can cause problems in thedental arch and adjacent teeth, which require special careand attention. There fore, clinicians should be capable ofdealing with this clinical situation in order to deliver optimaltreatment.

Clinicians have various definitions of “impaction.”Canine impaction can be defined as an unerupted toothafter its root development is complete; or a tooth stillunerupted when the corresponding tooth on the other side


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Impacted Maxillary Canines:Diagnosis and ManagementEffective Date: 09/1/2012 Expiration Date: 09/1/2015

of the arch has been erupted forat least 6 months and has acomplete root formation; or acondition in which a tooth isembedded in the alveolus and islocked in by bone, adjacentteeth, or other obstacles andcannot properly erupt into theoral cavity.1-5 This includes teethin which eruption is significantlydelayed and there is no clinicalor radiographic evidence thatfurther eruption is likely tohappen.1-5

Maxillary canines are amongthe last teeth to develop andhave the longest period ofdevelopment. They also have thelongest and most devious pathof eruption from the formationpoint lateral of the pisiform fossa to the final position in thedental arch.1-5 Therefore, thereis an increased potential formechanical disturbances resultingin displacement and impaction.

This article discusses theetiology, diagnosis, and clinicalmanagement of impactedmaxillary canine teeth.

PREVALENCE AND ETIOLOGYPermanent maxillary canine impaction has been reported inabout 1% to 2% of the population.1-5 This makes themaxillary canine the second most commonly impacted tooth,after third molars.1-7 Research indicates that women aretwice as likely as men to have impacted maxillary canines.1-11

The prevalence of impacted maxillary canines is between0.9% and 2%.1-5,11-13 It has been found that maxillaryimpacted canines occur palatally 85% of the time while only15% of impactions occur labially.1-5,14 According to Al-Nimriand Gharaibeh,15 palatal canine impaction occurred most

frequently in subjects with a Class II division 2 malocclusion.Among all patients with impacted canines, it was found thatunilateral impaction is much more common than bilateralimpaction.1-5,16 Maxillary canine impactions appear to be 10to 20 times more frequent than those in the mandible.1-5,17

While the etiology of impacted maxillary canines isthought to be multifactorial, they are not likely to originatefrom modified conditions in modern civilization such asfood texture or eating behavior;18 however, the exactetiology is still unclear.5,11 Possible causes for impactedcanines may include one or more of the following localfactors: inadequate space for eruption or early loss ofprimary canines; abnormal position of the tooth bud; the


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Impacted Maxillary Canines: Diagnosis and Management

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

a b

c d

e f

presence of an alveolar cleft, a cystic lesion or neoplasm;ankylosis; dilacerations of the root; an iatrogenic origin;and an idiopathic condition for no apparent reason.1-5

Systemic conditions such as endocrine deficiencies,malnutrition, febrile disease, or irradiation can also accountfor impacted canines.1-5

Currently, there are 2 major theories that have beenused to explain the cause of maxillary canine impaction: theguidance theory and the genetic theory. The guidancetheory states that excess space in the canine area of thedental arch during development and eruption owing to anabsent or malformed lateral incisor root causes the canine tolose its way and erupt improperly, because a permanentcanine tooth needs the distal aspect of a lateral incisor’s rootto guide it downward to the occlusion.19-22 The genetictheory claims that palatally impacted canines are the resultof a combination of multiple gene expressions which causedental anomalies such as congenital missing or peg-shapedlateral incisors due to a developmental disturbance of thedental lamina.23-25

CLINICAL DIAGNOSISImpacted canine teeth can be detected as early as age 8years.13,26 Clinical examination includes overall archinspection, palpation of canine bulges, mobility of primarycanines, and a review of the patient’s chronological age andhistory of eruption/exfoliation patterns of the dentition.Clinicians should be aware that there is a possibility of canineimpaction in the absence of canine bulges, abnormality inshape, missing lateral incisors, or less mobility of primarycanines. Unusual movement of lateral or central incisors can

also be a sign of root resorption due to pressure frommalposed canines. When there is the clinical presence of anyof these signs, radiographic examination should beperformed to confirm the diagnosis.1-5

RADIOGRAPHIC DIAGNOSIS Radiographic examination should be initiated with routineperiapical radiographs. However, when clinical signs lead toa possibility of canine im paction, radiographic evaluation isimmediately needed to confirm the diagnosis and assist indeveloping an appropriate treatment plan. There are variousradiographic methods that can be used to obtain neededinformation.

Periapical radiographs can be help ful by using at least 2radiographs at different angles to determine thebuccolingual position of a particular tooth. There are 2methods that are widely used: Clark’s rule and the buccalobject rule. Both use the different angulation of the x-raybeam to locate objects in different directions. Thesemethods, also known as same lingual-opposite-buccal rule,will make the ob jects on the lingual side move to the samedirection as the x-ray tube and objects on the buccal sidemove in the opposite direction.2,27

Panoramic radiographs are also widely used to locate theposition of impacted canines. They are part of thefundamental imaging taken for dental records and treatmentplanning. They provide an overall look of the entire dentitionincluding the temporomandibular joints (TMJs). Manyprediction values proposed in the literature come from thistype of radiograph.

Occlusal radiographs can identify the position of


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

a b c

impacted maxillary canines accurately inconjunction with routine periapicalradiographs. When properly obtained, theyprovide information about the buccolingualdirection of the crown and root of thecanine. They also provide informationrelated to the distance be tween the midlineand the position of the canines. Thedisadvantage of this radiograph is that itcannot provide any information about thevertical position of the canines.

Lateral cephalometric radio graphs canhelp determine the position of impactedcanines relative to other structures. They arehelpful because they are some of thefundamental radiographs that all patients havetaken prior to the beginning of orthodontictreatment. Maxillary canines can be locatedeasily on this radiograph as early as age 8 or9 years. Their inclination should be parallel tothe maxillary incisors.5

Posterior-anterior radiographs are alsouseful. Normal canines in this type ofradiograph should angle medially, and crownsshould be lower than the apex of the lateral incisors and thelateral border of the nasal cavity.8 However, this method stillprovides only 2-dimensional images with some degree ofsuperimposition. Nevertheless, this type of radiograph is notusually taken unless there are skeletal asymmetry and/ortransverse width issues. If there is any concern of impactionwith other anomalies, it might be better to utilize cone beamcomputed tomography (CBCT) instead.

CBCT has the great advantage of showing hard-tissuereconstruction in the area of interest in 3 dimensions,presenting a view without any superimposition,28 and alsoproviding a 1:1 magnification which can be used toreproduce panoramic or cephalometric images.6 Its use inorthodontics includes impacted teeth and TMJ evaluations,3-dimensional views of upper airways, assessment ofmaxillofacial growth, and development and dental ageestimation.29 CBCT scans are far better than conventionalpanoramic radiographs in verifying the orientation andlocation of the impacted canine and its relationship to

neighboring structures.6,30,31 This technique makesidentification of the exact position and shape of impactedcanines possible, which is crucial in treatment planning.Furthermore, it is very helpful in evaluating damage toadjacent teeth and the amount of surrounding bone.32 Themajor disadvantage of CBCT is the increased amount ofradiation exposure, which is at least 4 times higher than withordinary panoramic radiograms.6,29,33,34 There fore,orthodontists should consider cost-benefit outcomes beforeordering this radiograph.

PREDICTION OF MAXILLARY IMPACTIONThere are many predictive values and measurementsproposed in the literature to help determine the chance of aneventual impacted canine. Ericson and Kurol35 proposedpredicting canine impaction using the angulation, distance, andsector of the canines from a panoramic radiograph to determinethe chance of an impacted canine. That is, the deeper the cusptip from the occlusal plane, the more perpendicular to the


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

a b

c d

e f

midline, and the closer to the midline, thegreater the chance that tooth im paction willoccur and the longer the duration oftreatment.36Many studies have shown that themesiodistal position gives the best predictionvalue, while angulation and vertical positionshowed no statistical significance.8,37-40

Furthermore, an impacted canine which iscloser to the midline, or whose cusp tip ismesial to the midline of the lateral incisor, ismore likely to be palatally impacted, and rootresorptions are also more frequent.41

MANAGEMENT OF CANINEIMPACTIONMaxillary canine impaction usually needsmultidisciplinary care, which involves oralsurgery and periodontics along withorthodontic treatment. It is essential that thevarious clinicians working on the case havegood communication to provide optimal carefor the patient.2 The management ofimpacted canines can be divided into 2treatment categories: interceptive treatmentand corrective treatment.

Interceptive TreatmentPreventive modalities should be performed in cases thathave a strong possibility of canine impaction. Theelimination of obstacles to the path of eruption and theprovision of sufficient room for underlying canines areessential. Therefore, extraction of the primary canine isthought to be a proper interceptive treatment. Many claimthat this is the best treatment and it provides the moststable results.1-5 When appropriate, interceptive treatmentis the most advantageous in terms of cost-benefit ascompared to other more aggressive methods.11

However, there are many factors to be considered beforeinterceptive treatment can be done. A classic study fromEricson and Kurol35 showed that extraction of the primarycanines between the ages of 10 and 13 years will obtain afavorable result with most palatally erupted canines. If thecusp tip of a permanent maxillary canine in the panoramic

radiograph does not exceed the midline of the lateral incisor,the chance of the canine erupting normally is 91%; if the cusptip does exceed the midline of the lateral incisor, the chancefor normally erupting drops to 64%.35

Many modifications have been added to the extractionof primary canines to improve the results, including the useof cervical pull headgear,42 double extraction of the primaryca nine and the primary first molar,43,44 the use of atranspalatal arch (TPA),45 and the use of a rapid maxillaryexpansion in combination with a TPA.46 All of these showfavorable results as compared to the extraction of primarycanines alone. The selection of these modifications shouldbe based on individual clinical presentations.

Corrective TreatmentCorrective treatment is performed in situations whereorthodontists cannot render preventive or interceptivetreatment for some reason, or patients present beyond thepoint of prevention. There should be an attempt to bring


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

a b

c d

e f

impacted maxillary canines down to occlusionif possible, because permanent canines areimportant for both functional and aestheticreasons. Treatment can be divided into 2types, labial or palatal, depending on theposition of the ectopic canines.

Three techniques have been proposedby Kokich47 for uncovering a labiallyunerupted maxillary canine (gingivectomy,apically positioned flap, and closed eruptiontechnique). He also suggested thatorthodontists should evaluate 4 criteria todetermine the correct method foruncovering the tooth so the outcomeachieves the optimum periodontal health.47

These criteria include the distance betweenthe canine cusp and the mucogingivaljunction; the labiolingual position; themesiodistal position; and the amount ofgingiva in the area of the impacted canine.

In palatally impacted canines, theconcern about the lack of keratinized gingivadisappears because palatal tissue is a denseconnective tissue. Bishara2 suggested 2surgical methods for exposing the impacted canines: surgicalexposure followed by allowing spontaneous eruption; andsurgical exposure with auxiliary attachment for furtherorthodontic treatment.

The first method is useful when the canine has a correctaxial inclination and needs no upright correction during itseruption, but this method may increase treatment time andbe unable to control the path of eruption.2 Kokich47

suggested performing this method before the beginning oforthodontic treatment or during the late mixed dentitionbecause the tooth will erupt in a more favorable location,which will facilitate orthodontic movement without draggingthe crown through the palatal gingiva. Schmidt andKokich48 also reported that this technique had minimaleffects on the periodontium and that the overall effects onthe impacted canine appeared better than those from theclosed exposure and early traction techniques.

The second method is used when there is no eruptionforce left or the tooth does not lie in a favorable direction

and orthodontic force is required to move the impactedtooth away from the roots of the adjacent teeth and bring itto the proper position. After sufficient space has beencreated, surgical exposure is performed and the attachmentis placed. Light orthodontic force (not to exceed 60 g or 2oz) is then applied to move the tooth to the desired positionby various orthodontic techniques (Figures 1a to 5f).2,5

Removal of an impacted canine is one approach that israrely used but might need to be considered if the impactedcanine is ankylosed, has internal or external root resorption,severe dilaceration, or the position is undesirable and it isimpossible to bring it to the occlusion.2,5 Wriedt et al30

suggested that if the inclination of impacted canines inpanoramic radiographs is more than 45°, they will morelikely require surgical removal. If this is the final decision, theorthodontist must consider alternative treatments tosubstitute for the missing canine. The options can bepremolar substitution, autotransplantation, or prostheticsubstitution by working together with other specialties. The


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

a b

c d

e f

patient should be informed of all these treatment outcomepossibilities be fore beginning the treatment.5

SUMMARYCanine impaction is a relatively frequent clinical presentationin dentistry, with challenges that should be resolved. A goodunderstanding by the clinician of the situation and treatmentoptions can have a significant impact on the treatmentoutcome. Therefore, clinicians should be competent toperform the proper investigation, provide a correct diagnosis,develop an optimum treatment plan, and render appropriatetreatment for each individual patient so each patient realizesthe best outcome possible.

REFERENCES1. Schindel RH, Duffy SL. Maxillary transverse

discrepancies and potentially impacted maxillarycanines 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 andinterception of potential maxillary canine impaction. J Am Dent Assoc. 1998;129:1450-1454.

4. Ngan P, Hornbrook R, Weaver B. Early timelymanagement of ectopically erupting maxillarycanines. Semin Orthod. 2005;11:152-163.

5. Bedoya MM, Park JH. A review of the diagnosis andmanagement of impacted maxillary canines. J AmDent Assoc. 2009;140:1485-1493.

6. Jacobs R. Dental cone beam CT and its justified usein oral health care. JBR-BTR. 2011;94:254-265.

7. Litsas G, Acar A. A review of early displaced maxillarycanines: etiology, diagnosis and interceptivetreatment. Open Dent J. 2011;5:39-47.

8. Sambataro S, Baccetti T, Franchi L, et al. Earlypredictive variables for upper canine impaction asderived from posteroanterior cephalograms. AngleOrthod. 2005;75:28-34.

9. Cooke J, Wang HL. Canine impactions: incidence andmanagement. Int J Periodontics Restorative Dent.2006;26:483-491.

10. Proffit WR, Fields HW, Sarver DM. ContemporaryOrthodontics. 4th ed. St. Louis, MO: Mosby Elsevier;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 impactionof maxillary canines. Acta Odontol Scand.1968;26:145-168.

13. Ericson S, Kurol J. Radiographic assessment ofmaxillary canine eruption in children with clinical signs of eruption disturbance. Eur J Orthod. 1986;8:133-140.

14. Ericson S, Kurol J. Radiographic examination ofectopically erupting maxillary canines. Am J OrthodDentofacial Orthop. 1987;91:483-492.

15. Al-Nimri K, Gharaibeh T. Space conditions and dentaland occlusal features in patients with palatallyimpacted maxillary canines: an aetiological study. Eur J Orthod. 2005;27:461-465.

16. Peck S, Peck L, Kataja M. Site-specificity of toothagenesis in subjects with maxillary caninemalpositions. Angle Orthod. 1996;66:473-476.

17. Rebellato J, Schabel B. Treatment of a patient with an impacted transmigrant mandibular canine and apalatally impacted maxillary canine. Angle Orthod.2003;73:328-336.

18. Rajic S, Muretic Z, Percac S. Impacted canine in aprehistoric 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 maxillarypermanent canine in relation to anomalous or missinglateral incisors: a population study. Eur J Orthod.1986;8:12-16.

21. Becker A, Zilberman Y, Tsur B. Root length of lateralincisors adjacent to palatally-displaced maxillarycuspids. Angle Orthod. 1984;54:218-225.

22. Miller B. The influence of congenitally missing teethon the eruption of the upper canine. Dent Pract DentRec. 1963;13:497-504.

23. Pirinen S, Arte S, Apajalahti S. Palatal displacementof canine is genetic and related to congenital absenceof teeth. J Dent Res. 1996;75:1742-1746.

24. Peck S, Peck L, Kataja M. Concomitant occurrence ofcanine malposition and tooth agenesis: evidence oforofacial genetic fields. Am J Orthod DentofacialOrthop. 2002;122:657-660.

25. Frazier-Bowers SA, Puranik CP, Mahaney MC. Theetiology of eruption disorders—further evidence of a‘genetic paradigm.’ Semin Orthod. 2010;16:180-185.

26. Ericson S, Kurol J. Longitudinal study and analysis ofclinical supervision of maxillary canine eruption.Community Dent Oral Epidemiol. 1986;14:172-176.

27. Jacobs SG. Radiographic localization of uneruptedmaxillary anterior teeth using the vertical tube shift


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technique: the history and application of the methodwith some case reports. Am J Orthod DentofacialOrthop. 1999;116:415-423.

28. Kaeppler G. Applications of cone beam computedtomography in dental and oral medicine. Int J ComputDent. 2010;13:203-219.

29. Smith BR, Park JH, Cederberg RA. An evaluation ofcone-beam computed tomography use inpostgraduate orthodontic programs in the UnitedStates and Canada. J Dent Educ. 2011;75:98-106.

30. Wriedt S, Jaklin J, Al-Nawas B, et al. Impacted uppercanines: examination and treatment proposal basedon 3D versus 2D diagnosis. J Orofac Orthop.2012;73:28-40.

31. Walker L, Enciso R, Mah J. Three-dimensionallocalization of maxillary canines with cone-beamcomputed tomography. Am J Orthod DentofacialOrthop. 2005;128:418-423.

32. Ericson S, Kurol J. Resorption of incisors after ectopiceruption of maxillary canines: a CT study. AngleOrthod. 2000;70:415-423.

33. Batista WO, Navarro MV, Maia AF. Effective doses inpanoramic images from conventional and CBCTequipment. 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 usingmagnetic resonance imaging. Clin Oral Investig.2010;14:169-176.

35. Ericson S, Kurol J. Early treatment of palatallyerupting maxillary canines by extraction of the primarycanines. Eur J Orthod. 1988;10:283-295.

36. Crescini A, Nieri M, Buti J, et al. Orthodontic andperiodontal outcomes of treated impacted maxillarycanines. Angle Orthod. 2007;77:571-577.

37. Lindauer SJ, Rubenstein LK, Hang WM, et al. Canineimpaction identified early with panoramic radiographs.J Am Dent Assoc. 1992;123:91-92, 95-97.

38. Warford JH Jr, Grandhi RK, Tira DE. Prediction ofmaxillary canine impaction using sectors and angularmeasurement. Am J Orthod Dentofacial Orthop.2003;124:651-655.

39. Fleming PS, Scott P, Heidari N, et al. Influence ofradiographic position of ectopic canines on theduration of orthodontic treatment. Angle Orthod.2009;79:442-446.

40. Olive RJ. Factors influencing the non-surgical eruptionof palatally impacted canines. Aust Orthod J.2005;21:95-101.

41. Jung Y, Liang H, Benson B, et al. The assessment ofimpacted maxillary canine position with panoramicradiography and cone beam computed tomography.Dentomaxillofac Radiol. 2012;41:356-360. Epub 2011Nov 24.

42. Leonardi M, Armi P, Franchi L, et al. Two interceptiveapproaches to palatally displaced canines: aprospective longitudinal study. Angle Orthod.2004;74:581-586.

43. Alessandri Bonetti G, Incerti Parenti S, Zanarini M, etal. Double vs single primary teeth extraction approachas prevention of permanent maxillary canines ectopiceruption. Pediatr Dent. 2010;32:407-412.

44. Alessandri Bonetti G, Zanarini M, Incerti Parenti S, et al. Preventive treatment of ectopically eruptingmaxillary permanent canines by extraction ofdeciduous canines and first molars: A randomizedclinical trial. Am J Orthod Dentofacial Orthop.2011;139:316-323.

45. Baccetti T, Sigler LM, McNamara JA Jr. An RCT ontreatment of palatally displaced canines with RMEand/or a transpalatal arch. Eur J Orthod. 2011;33:601-607.

46. Sigler LM, Baccetti T, McNamara JA Jr. Effect of rapidmaxillary expansion and transpalatal arch treatmentassociated with deciduous canine extraction on theeruption of palatally displaced canines: A 2-centerprospective study. Am J Orthod Dentofacial Orthop.2011;139:e235-e244.

47. Kokich VG. Surgical and orthodontic management ofimpacted maxillary canines. Am J Orthod DentofacialOrthop. 2004;126:278-283.

48. Schmidt AD, Kokich VG. Periodontal response to earlyuncovering, autonomous eruption, and orthodonticalignment of palatally impacted maxillary canines. Am J Orthod Dentofacial Orthop. 2007;131:449-455.


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POST EXAMINATION INFORMATION

To receive continuing education credit for participation inthis educational activity you must complete the programpost examination and receive a score of 70% or better.

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POST EXAMINATION QUESTIONS

1. Which tooth has the longest and most tortuouseruption 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 theoral cavity?

a. Maxillary canine.

b. Mandibular second premolar.

c. Maxillary lateral incisor.

d. Mandibular third molar.

3. Which criterion (criteria) is (are) used to determinethe proper access for uncovering impacted maxillarycanines?

a. The distance between the canine cusp and themucogingival 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 localetiological factor of impacted 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) ofimpacted maxillary canines?

a. Absence of a labial bulge.

b. Peg shaped lateral incisor.

c. Retained primary canine.


6. When moving the x-ray tube in a mesial direction tolocalize the palatally impacted 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 theposition of impacted maxillary canines?

a. Periapical radiograph.

b. Lateral cephalogram.

c. Panoramic radiograph.

d. Cone beam computed tomography (CBCT).


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8. What is the advantage of CBCT?

a. Gives a 3-dimensional view.

b. Free of superimposition.

c. 1:1 magnification.


9. To predict impacted maxillary canines, which of thefollowing could be used?

a. Canine angulation.

b. Vertical distance of canine cusp from occlusal plane.

c. Mesiodistal position of the canine cusp.


10. One of the most negative consequences of impactedcanines 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 treatmentmodality for impacted maxillary canines?

a. Extraction of primary canine.

b. Extraction of primary canine in combination withcervical pull headgear.

c. Extraction of primary canine in combination withtranspalatal arch.


12. According to the study from Ericson and Kurol, withextraction of the primary canine at age 11 yearswhen the cusp tip of the permanent maxillary canineis between the central and the lateral incisors, thechance that this canine will erupt normally is:

a. 91%.

b. 75%.

c. 64%.

d. 50%.

13. Which of the following is NOT a surgical exposuretechnique for labially impacted canines?

a. Gingivectomy.

b. Coronally positioned flap.

c. Closed eruption technique.

d. Apically positioned flap.

14. Which surgical technique is NOT performed in thecase of a palatally impacted canine?

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 toorthodontically move an impacted canine is:

a. 30 g.

b. 45 g.

c. 60 g.

d. 90 g.

16. When an impacted canine has to be removed, whichof the following is a restorative treatment option?

a. Tooth autotransplantation.

b. Premolar substitution.

c. Prosthetic substitution.



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impacted maxillary canines: diagnosis and management · chair of the postgraduate orthodontic ......

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