1. Canine Impactions
Ectopic Eruption
Dr.Abu-Hussein Muhamad
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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
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3. Eruption process
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 Permanent tooth erupts
 Resorption of overlying bone
 Resorption of 1° tooth roots
 Eruption through gingiva

4. Interference with eruption
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 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
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6. 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
14 - 15 years Root completed
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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
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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
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9. Normal Development of the Maxillary
Canine
4-5 months
Development (calcification)
begins high in the maxilla
6 years Crown completed
10 years
palpable high in the buccal
vestibule
11-12 years Eruption
13.5 years Root completed
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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
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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
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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
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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
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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.
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15. Sequence of Eruption Permanent Teeth
MAXILLARY MANDIBULAR
First molar First molar
Central incisor Central incisor
Lateral incisor Lateral incisor
First premolar Canine
Second premolar First premolar
Canine Second premolar
Second molar Second molar

16. Clinical Signs of Maxillary Canine Impaction
Clinical signs
1. Failure to palpate canine bulge in buccal vestibule by 10 years
2. Immobility of the deciduous canine
3. Palatal bulge indicating possible underlying canine
4. Increased mobility, non-vital central or lateral incisors
5. Inadequate space within the dental arch for canine eruption
6. Flared lateral incisors – can also be normal
7. Asymmetry of eruption
1. Impacted maxillary canines in individuals > 40 years susceptible to
ankylosis
2. Failure of movement in an adolescent indicates ankylosis
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17. Lack of Space
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19. NA
Lack of space for canines
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20. 9 years 4 months
NA
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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
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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
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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
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10/31/05 Age 9 yrs 3 mos Patient A

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Patient A40°

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

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Age 12yrs. 7 mos
Patient B

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

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Mandibular canine impactionsMandibular canine impaction

39. Management of Impacted CaninesExtract
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)
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40. Impacted teeth - considerations
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 Surgical exposure
 Attachment to the tooth
 Orthodontic mechanics to bring the tooth into the
arch

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KF

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KF
4/13/07

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KF
12/1/07

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KF
8/7/08

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KF

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KF

47. KF 2-2009 47

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Impacted second molar

50. OUT OF NORMAL POSITION
Ectopic Eruption
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51. Ectopic Eruption
 Maxillary first molars
 Maxillary canines
 Mandibular canines
 Maxillary premolars
 Mandibular premolars
 Maxillary lateral incisors
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52. Ectopic eruption
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 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

53. Ectopic eruption
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 Permanent tooth causes resorption of tooth other
than the one it is supposed to replace or
 Resorption of an adjacent permanent tooth

54. Lateral incisors
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 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

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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
Ectopic Maxillary First Molar

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Age 8yr. O months
Patient Y

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Patient Y

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8 years 2 months
Patient Z

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6 weeks
Patient Z corrected

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Age: 7 years 8 months
Missing 2nd premolars

61. DOB 11-1-02, Pano 7-20-10 age 7 years 8 months W.E.
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62. W.E.
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63. Transposed Teeth S.N.
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64. Early Loss of Primary Teeth
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 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

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