The management of impacted canines is important in terms of esthetics and function. Clinicians must formulate treatment plans that are in the best interest of the patient and they must be knowledgeable about the variety of treatment options. When patients are evaluated and treated properly, clinicians can reduce the frequency of ectopic eruption and subsequent impaction of the maxillary canine. The simplest interceptive procedure that can be used to prevent impaction of permanent canines is the timely extraction of the primary canines. This procedure usually allows the permanent canines to become upright and erupt properly into the dental arch, provided sufficient space is available to accommodate them. In the present article, an overview of the incidence and sequelae, as well as the surgical, periodontal, and orthodontic considerations in the management of impacted canines is presented.
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
3
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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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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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
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
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