1. Canine Impactions Ectopic Eruption
Lecture 6
Ingrid Reed DDS, MS
Department of Orthodontics and Dentofacial Orthopedics
IMPACTIONS / ECTOPIC
ECTOPIC means out of the normal position. Malposition of a permanent tooth bud can lead to eruption in the wrong place. Contrast this with IMPACTED.
By definition IMPACTED TEETH are teeth that are so closely lodge in the alveolar bone as to be unable to erupt. Usually third molars and maxillary cuspids.
Impacted teeth may or may not be ectopic

2. Impacted vs. Ectopic eruption
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)
Causes of Interference with eruption Mosby Orthodontic Review page 19
Ectopic eruption is when a tooth erupts away from the normal position.
Multifaceted etiology:
Abnormal position of tooth bud in order of prevalence
Maxillary first molars
Maxillary canines
Mandibular canines
Maxillary premolars
Mandibular premolars
Maxillary lateral incisors
Ectopic eruption of permanent tooth an cause two things:
Undermining resorption of the primary tooth as in the case of first molars or
Non-resorption of primary roots usually
Mandibular second 1° molars (due to size) and
Maxillary second 1° molars due to palatal root.

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

6. Palpable high in the buccal vestibule
4-6 months
Development (calcification) begins high in the maxilla
6 years
Crown completed
10 years
Palpable high in the buccal vestibule
11-13years
Eruption
years
Root completed
Normal development of canine

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

9. Impacted third molars and canines

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 ~ years of age, when the maxillary canines migrate labially

12. Overretention of Primary Canines
Canine erupts 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
MAXILLARY
MANDIBULAR
First molar
Central incisor
Lateral incisor
First premolar
Canine
Second premolar
Second molar

16. Clinical Signs of Maxillary Canine Impaction
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. Lack of space for caninesNA
Noah Armstrong
Lack of space for canines

20. 9 years 4 months NA
Note need for several extraction

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
Clark’s rule – as change horizontal position of tube head, lingual position moves in same direction as tube, buccal moves in opposite direction.

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

24. Normal development

25. Megan Ehrnman

26. Canines impacted with resorption of lateral roots

27. Central and lateral incisor roots resorbed

28. Angulation of the lateral and central due to pressure of the canine

29. 10/31/05
Age 9 yrs 3 mos
Patient A
Canine impactions and impacted premolars due to lack of space
Recommend TE deciduous canines and 1st primary molar on right and 2nd primary molar on left.
Will later TE 1st premolar on left and leave in Class II on left. Distalizing the 1st molar could cause second molar impaction
Patient did nothing

30. Patient A
40°

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

32. Age 12yrs. 7 mos
Patient B
The first thing you should do is extract the deciduous canines, there is no guarantee that the canines will come in but if you do nothing there is a much greater chance they will be impacted, especially when crossing over the roots of the laterals.

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

34. Horizontal impactions, note mandibular canine

38. Mandibular canine impactions
Amy Risch
Mandibular canines can be impacted as well

39. Management of Impacted Canines
Extract
Deciduous Canine
Age 10
May help normalize eruptive path in palatally displaced canine
Radiographic improvement in 6-18 months
No Treatment
Poorly motivated patient
Inform of resorption risk and cystic change within canine follicle
Monitor radiographically every 12 months
Orthodontic
Alignment
Following surgical exposure
Gold chain bonded to the tooth
Space created
TPA in place
Surgical
Removal
Very unfavorable canine position
Poorly motivated patients
Orthodontic treatment contraindicated
Severe crowding (substitute 1st premolar)

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

41. KF
Case of palatally impacted canine

42. KF
Canine palatally located
4/13/07

43. KF
12/1/07

44. KF
8/7/08

45. KF

46. KF

47. KF

49. Impacted second molar

50. Ectopic Eruption
Out of normal position

51. Ectopic Eruption Maxillary first molars Maxillary canines
Mandibular canines
Maxillary premolars
Mandibular premolars
Maxillary lateral incisors

52. Ectopic eruption Malposition of a permanent tooth bud
Eruption in the wrong place
Most common – maxillary first permanent molars
Ectopic eruption of other teeth rare but can lead to transposition
pgs 139, ,

53. Ectopic eruption
Permanent tooth causes resorption of tooth other than the one it is supposed to replace or
Resorption of an adjacent permanent tooth
Can be 1st permanent molar or lateral incisor causing resorption of primary canine

54. Lateral incisors
Ectopic eruption causes resorption of primary canine – indicates lack of space
Loss of only one primary canine can cause midline shift – need to maintain lateral incisor position with appliance or
Extract contralateral canine
Loss of mand. 1° canines causes incisors to tip lingually with loss of arch perimeter
Space analysis important – passive LLA or active LLA

55. Ectopic Maxillary First Molar
Prevalence
2-6% (20-25% if cleft lip/palate)
Etiology
Crowding / large crown / mesial eruption
MANAGEMENT
OBSERVE
Active Treatment
May correct spontaneously
Rarely after age 8 years
Brass wire or elastic separator – mild cases
Distalizing appliances more serve cases
Extract primary if pulpal involvement – space maintainer or regainer

56. Age 8yr. O months Patient Y Zumwalt 495-5-27
Ectopic eruption of maxillary laterals (resorbing maxillary canines)
Mandibular lateral resorbing canine
Age 8yr. O months

57. Patient Y
Zumwalt

58. 8 years 2 months
Patient Z
Emily Lopez

59. 6 weeks
Patient Z corrected

60. Missing 2nd premolars Age: 7 years 8 months
Morgan Brown Consider removing 2nd primary molar and allowing 1st permanent molar to move mesially
Age: 7 years 8 months

61. DOB 11-1-02, Pano 7-20-10 age 7 years 8 months W.E.
Evans, W.

62. W.E.

63. Transposed Teeth
S.N.

64. Early Loss of Primary Teeth
Early loss of 2nd 1° molar
Mesial drift of first permanent molar
Greater if no occlusal forces are on it
Early loss of 1° first molar or canine
Distal drift of incisors
Force from active contraction of transseptal fibers
Pressure from the lips and cheeks
pgs –