Canine Impactions Ectopic Eruption

1. Canine Impactions Ectopic Eruption Lecture 6 Ingrid Reed DDS, MS Department of Orthodontics and Dentofacial Orthopedics

2. Impacted vs. Ectopic eruption • Impacted • Condition of being firmly lodged (impacted in alveolar bone) or wedged by a physical barrier, usually other teeth, so it is prevented from erupting • Ectopic eruption • Located away from the normal position

3. Eruption process • Permanent tooth erupts • Resorption of overlying bone • Resorption of 1° tooth roots • Eruption through gingiva

4. Interference with eruption • Ectopic eruption of permanent tooth • Undermining resorption of the 1° tooth • Non-resorption of 1° roots, may be result not cause • Supernumerary teeth – remove as indicated • Heavy fibrous gingiva – may need to expose tooth • Sclerotic bone – may need to expose tooth • Ankylosed tooth • Lack of space – consider serial extraction or orthodontics (age/crowding dependent)

5. Normal Development of Maxillary Canines • Age 3 – located high in maxillary bone –mesially & lingually directed crown • Intrabony migration – lateral roots – ‘ugly duckling’ • Spontaneous closing of midline diastema as canines simultaneously upright and erupt

7. Prevalence of Maxillary Canine Impaction • Maxillary canine 2nd most frequently impacted tooth • Third molars most frequently impacted • Maxillary 50 times greater than mandibular • Palatal versus buccal - range 2:1 to 12:1

8. Etiology - Maxillary Canine Impaction • Availability of space in arch • Eruption path • Horizontal angulation of tooth • Trauma to 1° tooth bud • Disturbance in eruption sequence • Rotation of tooth buds • Premature root closure

10. Maxillary Canine Impaction – Diagnostic Problem • Usually last tooth to replace primary tooth • Fewer radiographs taken at recall – bitewings may not show canines • Need knowledge of crown development, root development and eruption

11. Impacted Maxillary Canines • The most opportune time to observe the maxillary canines beginning their eruption and detect an eventual impaction is when children are ~ 8 - 9 years of age, when the maxillary canines migrate labially

12. Overretention of Primary Canines • Canine erupts 11-13 years • Primary canine not exfoliated, overretention may be result of, not cause of, ectopic position of canine • Permanent canine has not precipitated vertical resorption of the primary tooth’s root • Canine crown inclined too far mesially • Canine crown having slipped over the root of the permanent lateral incisor, is deprived of the eruptive guidance of the lateral incisor’s distal surface

13. Extraction of Primary Canines • Canines begin to deviate from a normal eruptive position in patients ~9 years of age • If permanent canine path is errant, extract primary canines at age 10. • Teeth take the path of least resistance • Improvement usually seen in 6-18 months

14. Extraction of Primary Canines Degree of horizontal angulation important Study by Ericson an Kurol • 78% of canines changed angulation within 18 months of 1° canine extraction • 91% if tip of canine cusp had not passed midline of lateral root • Must have space for canine to erupt- maintain or create after primary extraction.

15. Sequence of Eruption Permanent Teeth

16. Clinical Signs of Maxillary Canine Impaction Clinical signs • Failure to palpate canine bulge in buccal vestibule by 10 years • Immobility of the deciduous canine • Palatal bulge indicating possible underlying canine • Increased mobility, non-vital central or lateral incisors • Inadequate space within the dental arch for canine eruption • Flared lateral incisors – can also be normal • Asymmetry of eruption • Impacted maxillary canines in individuals > 40 years susceptible to ankylosis • Failure of movement in an adolescent indicates ankylosis

17. Lack of Space

19. NA Lack of space for canines

20. 9 years 4 months NA

21. Screening panoramic radiograph • Dental age 8-9 • Full eruption of • Maxillary central and lateral incisors • Mandibular central and lateral incisors • All four first molars • Anytime prior with cause

22. Radiographic Signs of Probable Canine Impaction • Long axis of the canine is angled more than 10 ° to the vertical plane. The greater the angle the more likely a problem. • 25° - impaction • Canine overlaps the lateral or central incisor root • Parallax technique shows buccal/palatal position

23. Clark’s rule – Horizontal change • The lingual object moves in the same direction as the x-ray source • The buccal object moves in the opposite direction of the x-ray source because it is farther away from the film than the root of the lateral incisor

29. Age 9 yrs 3 mos 10/31/05 Patient A

30. 40° Patient A

31. 2 yrs 5 mo later Age 11 yrs. 8 mos Patient A

32. Age 12yrs. 7 mos Patient B

33. 4 years 3 months later Age 16 yrs 10 months Patient B

38. Mandibular canine impactions Mandibular canine impaction

39. Management of Impacted Canines

40. Impacted teeth - considerations • Surgical exposure • Attachment to the tooth • Orthodontic mechanics to bring the tooth into the arch

41. KF

42. KF 4/13/07

43. KF 12/1/07

44. KF 8/7/08

45. KF

46. KF

47. KF 2-2009

49. Impacted second molar

50. Ectopic Eruption Out of normal position