diagnosis and management of impacted maxillary canines · impacted maxillary canine position in...

4 Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0001

Review Article

Maxillary canines play an important role in facial esthetics, since the canine eminence can support the alar

and the upper lip. Impacted maxillary canines is a common problem which requires multidisciplinary diagnosis

and treatment in dental clinic. The aim of this review is to integrate the studies that include clinical diagnosis

and guidelines for management of canine impaction. (Taiwanese Journal of Orthodontics. 31(1): 04-11, 2019)

Keywords: canine impaction; surgical exposure; orthodontic biomechanics.

Diagnosis anD ManageMentof iMpacteD Maxillary canines

Yu-Cheng Hsu, Chia-Tze Kao, Chih-Chen Chou, Wen-Ken Tai, Po-Yu YangOrthodontic Department, Chung Shan Medical University Hospital, Taichung, Taiwan

College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan

INCIDENCE OF CANINE IMPACTION

The incidence of maxillary canine impaction was

reported as second to the third molar.1 The incidence was

reported varies, from 0.92% to 2.2%, higher in some

races. Dachi and Howell reported an incidence of 0.92%,

while Thilander and Myrberg reported 2.2% in 7-13 years

of age.2,3

Ericson and Kurol also reported an incidence

of 1.7%, more common in women (1.17%) than in men

(0.51%) as a ratio about 2:1.4

Bilateral impactions present in about 8% of people

with maxillary impacted canines. Palatally impacted

canine occurs more than labially impacted canine by

the ratio of 2:1 to 3:1.5 Jacoby believed that most labial

impactions could erupt to a relatively labial and superior

position.6 He declared that 85% of palatally impacted

canines have enough space for eruption, whereas only

17% of labially impacted canines have enough space.

There were 83% of labially impacted canines cases who

had arch length deficiency, a primary etiologic factor for

labially impacted canines. However, palatally impacted

canines seldom erupt without surgical or orthodontic

intervention due to the thick cortical bone and dense

palatal mucosa. Moreover, palatally impacted canines are

often in a horizontal or oblique direction.

The prevalence of impacted maxillary canines

in Chinese people was different from Caucasians.7 The

ratio of labially and palatally impacted canines is 2.1: 1,

and the ratio of male to female having maxillary canine

impactions is 1.8:1.

ETIOLOGY AND DEVELOPMENTAL CONSIDERATION

Maxillary canines take the longest period to develop

and the longest course to travel into dental occlusion.8

During the development, the crowns of canines are close

to the roots of lateral incisors. Early correction of the root

Received: August 29, 2018 Revised: September 06, 2018 Accepted: March 16, 2019Reprints and correspondence to: Dr. Po-Yu Yang, College of Oral Medicine, Chung Shan Medical University No.110, Sec. 1, Jianguo N. Rd., South Dist., Taichung City 402, Taiwan Tel: 886-4-24718668 Fax: 886-4-24759065 E-mail: [email protected]

5Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0001

Impacted Maxillary Canine

position in maxillary lateral incisor with distal tipping and

flaring might either cause the impaction of canines or root

resorption of lateral incisors.9

The etiology of maxillary canine impaction may

be genetic, generalized or localized (Table 1). The labial

impaction is often the result of crowding or shifting of

the maxillary dental midline,10

whereas the etiology of

palatal impaction is hypothesized to be multifactorial and

genetic.11

Two main theories have been proposed to explain

the presence of palatally impacted canines: the guidance

theory and the genetic theory.1 The guidance theory

suggested that the length and timing of root formation

of the lateral incisors is crucial for guiding the mesially

erupting canine to a more favorably distal and incisal

direction.12

Becker et al. reported an increase of 2.4 times

of incidence of palatally impacted canines if absence of

lateral incisors.13

The genetic theory suggested that the

genetic factors are primary origin of palatally displaced

maxillary canines, resulting in the familial and bilateral

occurrence as well as gender preference.14

SEQUELAE OF IMPACTION

According to the study of Shafer et al., there are

some following sequelae of canine impaction:15

● Labial or lingual malpositioning of the impacted tooth● Migration of the neighboring teeth and loss of arch length● Internal resorption● Dentigerous cyst formation● External root resorption of the impaction or the

neighboring teeth● Infection particularly with partial eruption● Referred pain

Table 1. The etiologic factors of canine impaction.45,46


2. Occlusal films can also help to determine the

buccolingual position of the impacted canine.20

3. Panoramicfilms

Katsnelson et al. revealed 26.6 times of chances

for labially impacted canine if the angulation of the

impaction and the horizontal reference line is more

than 65°.21

4. Frontal/lateral cephalograms can sometimes be used

to determine the position of the impacted canine in

relation to adjacent structures such as the maxillary

sinus and the floor of the nose.

5. CT/CBCT is an accurate technique for identifying

and locating the position of the impacted canine, and

assessing if any damage to the roots of adjacent teeth

and the amount of bone surrounding the teeth, yet

increasing the costs, time and radiation exposure.22,23

CONSIDERATION OF TREATMENT PLANNING

A number of factors can affect the prognosis and

should be considered before making the treatment

decision, including the patient’s age and cooperation,

general and dental health, skeletal variation and dental

spacing or crowding (Table 2).

Treatment optionsVarious treatment options are available including:

24

1. No treatment

No active treatment is recommended when:25

● the patient does not request treatment● there is no sign of resorption or other pathology of the

adjacent teeth ● the canine is severely displaced with no evidence of

pathology● the canine is remote from the dentition with a good

contact between lateral incisor and first premolar● the primary canine provides good esthetics/prognosis

Hsu YC, Kao CT, Chou CC, Tai WK, Yang PY

DIAGNOSIS

The diagnosis and localization of impacted maxillary

canine should be based on clinical and radiographic

evaluation.

Clinical EvaluationThe amount of space for eruption, the morphology

and position of the adjacent teeth, the contour of the bone,

the mobility of teeth should be considered through clinical

evaluation. Clinical signs of canine impaction are listed as

followings:16

(1) Delayed eruption of the permanent canine or

prolonged retention of the primary canine

(2) Absence of a normal labial canine bulge

On the other hand, the absence of the canine bulge

at earlier ages should not be considered as an only

indicator of canine impaction. According to study of

Ericson and Kurol, 29% of children had nonpalpable

canines at age of 10; but only 5% at age of 11, and

only 3% at later ages.17

(3) Presence of a palatal bulge

(4) Delayed eruption, distal tipping, or migration of the

lateral incisor

Radiographic EvaluationRadiographic evaluation includes periapical

radiographs, occlusal films, panoramic radiographs, lateral

cephalograms and cone-beam computed tomography

(CBCT).18

1. Periapicalfilms: A second periapical film is required.

The lingual object moves in the same direction of

the cone; the buccal object moves in the direction

opposite to the direction of the cone, as “same-lingual,

opposite-buccal (SLOB)” rule.19

(1) Tube-shift technique or Clark’s rule Two films are taken at different horizontal

angulation of the cone.

(2) Buccal-object rule Two films are taken at different vertical angulation

of the cone.


In this case, periodical monitoring is suggested in the

cases of cystic degeneration, root resorption and the other

possible complications. In most cases, the root of primary

canine will eventually resorb and need extraction.24

2. Interceptive treatment

The primary canine is usually extracted to facilitate

the eruption of the permanent canine or to let the

permanent canine move to a favorable position; it avoids

excessive duration, expense, and complex treatment.

Williams suggested extraction of the primary canines

at the age of 8 or 9 in Class I uncrowded cases for self-

correction of a labial or intra-alveolar canine impaction.26

Ericson and Kurol suggested that extraction of the primary

canine before the age of 11 will normalized the position

of the canines in 91% of the cases if the crown tip is distal

to the midline of the lateral incisor, while only 64% of the

cases can be normalized if the crown tip is mesial to the

midline of the lateral incisor.27

Baccetti et al. declared that

the extraction of the primary canine is an effective way to

normalize the eruption of maxillary canine by 2 times the

possibility than in untreated cases.28

Therefore, extraction of the primary canine before

the age of 11 as an interceptive approach to prevent

canine impaction can be concluded. Then clinical and

radiographic re-evaluation should be taken at 6-month

intervals. If there is no improvement within 12 months, an

alternative treatment is indicated.27


Table 2. Factors influencing the treatment decision of an impacted maxillary canine.47


3. Extraction

The extraction of the impacted canine is seldom

considered for the functional occlusion might be

compromised, yet it might be an alternative, only if:29

● it is ankylosed and cannot be transplanted● it is undergoing external or internal root resorption● its root is severely dilacerated● the impaction is severe● the occlusion is acceptable, with the first premolar in

the position of the canine and well-aligned● there are pathologic changes● the patient does not desire for orthodontic treatment

If the impacted canine is going to be extracted, then

the decision should be made whether to replace the canine

with first premolar or to restore the canine space with

prosthesis.

If the canine space is going to be replaced with the

first premolar by orthodontic protraction, several factors

should be taken into consideration; such as the lingual

cusp interference of premolar, tooth size discrepancy, the

unilateral mechanics, the smile esthetics. For orthodontic

alignment, it may need to intrude the first premolar

and restoring the premolars with composite resin or

porcelain prosthesis, or to apply negative crown torque

and mesiopalatal rotation to imitate the appearance of a

canine. The canine guidance can be replaced by premolar

guidance or group function.30

4. Autotransplantation

The ideal stage for autotransplantation is at 50-75 %

of the root formation.31

The prognosis of transplantation

of the impacted canine in adult is poor, most of them need

endodontic treatment.32

5. Surgical exposure and orthodontic treatment

Considerations for exposing the impacted canine

should be emphasized, including surgical technique,

marginal gingival placement, control of inflammation,

magnitude of force, atraumatic surgery, and proper

gingival attachment.

Three main techniques may be performed:33

(1) Excisional uncovering (gingivectomy)

(2) Apically positioned flap (APF)

(3) Closed technique: Including vestibular incision

subperiosteal tunnel access (VISTA) technique.34,35

Kokich had proposed 4 criteria for surgical exposure:33

(1) Labiolingual position of the crown

If the canine is impacted labially, then the 3

techniques are viable; if the canine is impacted at the

center of the alveolus, then APF and gingivectomy

might not be feasible for the extensive bone removal.

(2) Vertical position of the tooth relative to the

mucogingival junction (MGJ)

If the crown is positioned apically to MGJ, then

closed technique is the most appropriate approach.

If the crown is slightly apical positioned, then APF is

used.

If the crown is positioned coronally to MGJ, then any

of the 3 techniques can be used.

(3) Amount of attached gingiva

The amount of 2-3 mm of attached gingiva should

be sufficient after eruption. If there is no sufficient

attached gingiva, APF could bring out to preserve the

attached gingiva for periodontal health.

(4) Mesiodistal position of the crown

If the crown is posi t ioned mesial ly, APF is

recommended for it could be difficult to move the

tooth through the alveolus unless complete exposure.

Orthodontic considerationsWhich biomechanics to be used depends on several

factors, such as the location and the angulation of the

canine relative to the dental arch, the adjacent teeth and

the occlusal plane.36

The appliances such as ligature wires, brackets,

buttons or eyelets may be used to attach onto impacted

tooth. Various traction methods has been proposed,

including light wires, auxiliary springs or arms from

main the archwire or transpalatal arch, mousetrap loops,



K-9 spring, ballista loops and Kilroy I, II springs.33,37,38

Also, temporary anchorage devices (TADs) can be

reliable and then brackets bonding can be delayed until

canine eruption.39

Hawley type removable appliances

can be used as anchorage unit; however, the need for

patients’ cooperation, limited control of tooth movement

and the inability to treat complex malocclusions are the

disadvantages.24

Initially, the arch should be leveled and aligned until

a rigid rectangular wire is placed. Then enough space is

required before the surgical exposure. Whatever materials

are used, the direction of the force applied on the impacted

tooth should first move the impaction away from the root

of the adjacent tooth. The force should be light, no more

than 2 oz (60 g).24

When a palatally impacted canine is encountered,

the tooth surface available for bonding is often on the

palatal side. However, Becker reckoned that the palatal

surface is an undesirable site for applying traction force

from main archwire, for it could embed the buccal surface

of the crown and produce periodontal problems and

make it harder to move the canine to a better position

and angulation.40

Therefore, it would be better to let the

canine erupt vertically until the buccal surface could be

bonded.41

As for the labially impacted canines, periodontal

conditions such as bony dehiscence and recession of

labial gingival margin should be prevented by guide the

impacted tooth to erupt between the alveolar cortical

plates.42

RETENTION

Becker found an increase incidence of rotations or

spacings on the impacted side (17%), as compared to

the control side (8.7%).43

Besides, the rebound of canine

extrusion might happen in some cases as well, therefore,

circumferential supracrestal fiberotomy is recommended

to prevent relapse of these conditions.44

CONCLUSION

Impacted maxillary canine is the second most

frequent impaction, early diagnosis and intervention

make the best solution. The keys to treat the impacted

canines successfully include accurate localization,

use of appropriate surgical procedure and orthodontic

biomechanics.

REFERENCES

1. Litsas G, Acar A. A Review of Early Displaced

Maxil lary Canines: Et iology, Diagnosis and

Interceptive Treatment. Open Dent J 2011;5:39-47.

2. Dachi SF, Howell FV. A survey of 3,874 routine full

mouth radiographs. Oral Surg Oral Med Oral Path

1961;14:1165-9.

3. Thilander B, Myrberg N. The prevalence of

malocclusion in Swedish school children. Scand J

Dent Res 1973;81:12-20.

4. Ericson S, Kurol J. Radiographic assessment of

maxillary canine eruption in children with clinical

signs of eruption disturbances. Eur J Orthod

1986;8:133-40.

5. Fournier A, Turcotte J, Bernard C. Orthodontic

considerations in the treatment of maxillary impacted

canines. Am J Orthod 1982;81:236-9.

6. Jacoby H. The et iology of maxil lary canine

impactions. Am J Orthod 1983;84:125-132.

7. Zhong YL, Zeng XL, Jia QL, Zhang WL, Chen L.

Clinical investigation of impacted maxillary canine.

Zhonghua Kou Qiang Yi Xue Za Zhi. 2006;41:483-5.

8. Dewel BF. The upper cuspid: its development and

impaction. Angle Orthod 1949;19:79-90.

9. Broadbent BH. Ontogenic development of occlusion.

Angle Orthod 1941;11:223-41.

10. Kokich VG. Surgical and Orthodontic Management

of impacted maxillary canines. Am J Orthod Dentofac

Orthop 2004; 126:278-283.



11. Pirinen S, Arte S, Apajalahti S. Palatal displacement

of canine is genetic and related to congenital absence

of teeth. J Dent Res 1996;75:1742-1746.

12. Brin I, Becker A, Shalhav M. Position of the maxillary

permanent canine in relation to anomalous or missing

lateral incisors: A population study. Eur J Orthod

1986;8:12-16.

13. Becket A, Smith P, Behar R. The incidence of

anomalous lateral incisors in relation to palatally

displaced cuspids. Angle Orthod 1981;51:24-9.

14. Peck S, Peck L, Kataja M. Site-specificity of

tooth maxillary agenesis in subjects with canine

malpositions. Angle Orthod 1996;66:473-476.

15. Shafer WG, Hine MK, Levy BM, Editors. A Textbook

of Oral Pathology. 2nd Ed. Philadelphia: WB

Saunders; 1963.

16. Ngan P, Hornbrook R, Weaver B. Early timely

management of ectopically erupting maxillary

canines. Seminars in Orthodontics 2005;11:152–163.

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

of clinical supervision of maxillary canine eruption.

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

18. Bishara SE. Clinical management of impacted

maxillary canines. Seminars in Orthodontics

1998;4:87-98.

19. Langland OE, Francis SH, Langlois RD. Atlas of

special technics in dental radiology. In: Textbook of

Dental Radiology. Springfield, IL: Charles C. Thomas

Publishes; 1984.

20. Ericson S, Kurol J. Radiographic examination of

ectopically erupting maxillary canines. Am J Orthod

Dentofac Orthop 1987; 91(6) 483-492.

21. Katsnelson A, Flick WG, Susarla S, Tartakovsky

JV, Miloro M. Use of panoramic x-ray to determine

position of impacted maxillary canines. J Oral

Maxillofac Surg. 2010;68:996-1000.

22. Liu DG, Zhang WL, Zhang ZY, Wu YT, Ma XC.

Localization of Impacted Maxillary Canines and

Observation of Adjacent Incisor Resorption with

Cone-Beam Computed Tomography. Oral Surg Oral

Med Oral Pathol Oral Radiol Endod 2008;105:91-98.

23. Alqerban A, Jacobs R, Keirsbilck P, Aly M, Swinnen

S, Fieuws S, Willems G. The effect of using CBCT

in the diagnosis of canine impaction and its impact

on the orthodontic treatment outcome. J Orthodc Sci

2014;3:34–40.

24. Bishara SE. Clinical management of impacted

maxillary canines. Seminars in Orthod 1998;4:87-98.

25. Mc Sherry PF. The ectopic maxillary canine: a review.

Br J Orthod 1998;25:209-216.

26. Williams BHJ. Diagnosis and prevention of maxillary

cuspid impaction. Angle Orthod 1981;51:30-40.

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

erupting maxillary canines by extraction of the

primary canines. Eur J Orthod 1988;10: 283-295.

28. Baccetti T, Leonardi M, Armi P. A randomized clinical

study of two interceptive approaches to palatally

displaced canines. Eur J Orthod 2008;30:381–385.

29. Bishara SE. Impacted maxillary canines: a review. Am

J Orthod Dentofac Orthop 1992;101:159-171.

30. Mirabella D, Giunta G, Lombardol. Substitution of

impacted canines by maxillary first premolars: a valid

alternative to traditional orthodontic treatment. Am J

Orthod and Dentofac Orthop 2013; 143:125-33.

31. Kristerson L. Autotransplantation of human premolars.

Int J Oral Surg 1985;14:200-213.

32. Ahlberg K, Bystedt H, Eliasson S, Odenrick L. Long-

term evaluation of autotransplanted maxillary canines

with completed root formation. Acta Odontologica

Scandinavica 1983;41: 23–31.

33. Kokich VG. Surgical and orthodontic management

of impacted maxillary canines. Am J Orthod and

Dentofac Orthop 2004;126:278-283.

34. Zadeh HH. Minimally invasive treatment of maxillary

anterior gingival recession defects by vestibular

incision subperiosteal tunnel access and platelet-

derived growth factor. Int J Period Rest Dent

2011;31:653-660.



35. Chen CK, Chang CH, Roberts WE. Class I II multiple

gingival recession: vestibular incision subperiosteal

tunnel access (VISTA) and platelet-derived growth

factor. Int J Orthod Implantol 2014;35:22-36.

36. Kokich VG, Mathews DA. Impacted teeth: surgical

and orthodontic considerations. In: JA McNamara Jr.

(ed.) Orthodontics and Dentofacial Orthopedics. Ann

Arbor, Michigan: Needham Press; 2001.

37. Bowman SJ, Carano A. The Kilroy spring for

impacted teeth. J Clin Orthod 2003;37:683-688.

38. Shastri D, Nagar A, Tandon P. Alignment of palatally

impacted canine with open window technique and

modified K-9 spring. Contem Clin Dent 2014;5:272–

274.

39. Park HS, Kwon OW, Sung JH. Micro-implant

anchorage for forced eruption of impacted canines. J

Clin Orthod 2004;38:297-302.

40. Becker A, Shpack N, Shteyer A. Attachment bonding

to impacted teeth at the time of surgical exposure. Eur

J Orthod 1996;18:457-463.

41. Sinha PK, Nanda RS. Management of impacted

maxillary canines using mandibular anchorage. Am J

Orthod Dentofac Orthop 1999;115:254-257.

42. Crescini A, Nieri M, Buti J, Baccetti T, Pini Prato GP.

Pre-treatment radiographic features for the periodontal

prognosis of treated impacted canines. J Clin Period

2007;34:581-587.

43. Becker A, Kohavi D, Kohavi D, Zilberman Y.

Periodontal status following the alignment of palatally

impacted canine teeth. Am J Orthod 1983;84:332-336.

44. Edwards JG. A long-term prospective evaluation of the

circumferential supracrestal fiberotomy in alleviating

orthodontic relapse. Am J Orthod Dentofacial Orthop

1988;93:380-7.

45. Bedoya MM, Park JH. A review of the diagnosis and

management of impacted maxillary canines. J Am

Dent Assoc 2009;140:1485-1493

46. Manne R, Gandikota C, Juvvadi SR, Medapati Rama

H, Anche S. Impacted canines: etiology, diagnosis,

and orthodontic management. J Pharm Bioall Sci

2012;4:234-8.

47. Charles A, Duraiswamy S, Krishnaraj R, Jacob S.

Surgical and orthodontic management of impacted

maxillary canines. J Res Dent Sci 2012;3:198-203.


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