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I) Impacted Upper Canines
• A canine that is prevented from erupting into its normal functional
position by bone, tooth or fibrous tissue.
• The palatal impaction of canines presents a special challenge in practice
of orthodontics. Three questions that immediately come to the mind of
the clinician after identification of an impaction are:
Eruption of maxillary canine
1. Has long path of eruption from the infra-orbital
place along the roots of upper laterals causing ugly
duckling space which resolve later, and then pass
along the buccal surface of the primary canine .
2. Upper canine erupts at 11-12yrs.
3. 3's palpable in buccal sulcus by 8-10 yrs.
(Ferguson, 1990 )
o Developmentally absent 3's: 0.08% (Brin et al, 1986)
o Impacted 3's: 2% (Ericsson, 1986)
o F:M = 70%:30%
o Unilateral: bilateral = 4:1
o Palatal: 61%; in line of arch: 34%; buccal: 4.5% (Mandal, 2000, Brin et al, 1986)
o Associated with peg lateral incisors (Brin et al 1986)
o High incidence associated with CI II div 2 malocclusions (Moosy, 1994)
• An long and tortious
• Earlier development than
adjacent lateral incisors.
• Small or developmentally
absent lateral incisors.
• Trauma with displacement
of tooth bud.
• Intra-alveolar Obstruction.
• Retained deciduous teeth.
• supernumerary tooth or
• Pathology, such as a
• thickened mucosa
following early extraction
of deciduous teeth
• Dental crowding.
• Endocrine deficiencies.
• Febrile disease.
• Irradiation .
• Heridetity .
• Malposed tooth germ.
• Presnse of an alveolar
Theories of impaction :
• Two main theories have been proposed :
A ) Guidance theory :
underlines a role of the lateral incisor root in guiding the
erupting canine crown in the proper direction towards
the dental arch.
• With small or developmentally absent lateral incisors,
the incidence are three times (Becker)
• Associated with peg lateral incisors (Brin et al 1986)
• High incidence associated with CI II div 2
malocclusions (Moosy, 1994)
B) Genetic theory: (Peck et al., 1994, 1995),
The palatal displacement of the canine is genetically determined.
This theory is supported by other dental anomalies frequently
occurring in patients with the ectopically erupting canines, so-called
microsymptoms (e.g. small teeth, enamel hypoplasia, aplasia of second
premolars, infraocclusion of primary molars, etc.)
Occurrence with specific race
Occurrence in family
Occurrence in female more than male
Occurrence with specific syndrome
Occurrence unilateral: bilateral is 4:1
Diagnosis of unerupted upper canine
A ) History and examination :
Practitioners should suspect ectopia if the canine is not palpable in
the buccal sulcus by the age of 10-11 years, if palpation indicates an
asymmetrical eruption pattern or the position of adjacent teeth
implies a malposition of the permanent canine.
The patient with an ectopic maxillary canine must undergo a
comprehensive assessment of the malocclusion, including accurate
localization of the canine
B ) Inspection
Clinical signs of impacted 3s :
• Delayed eruption.
• Asymmetrical eruption.
• Prolonged retained of C.
• Absence of buccal bulge at age of 10 years.
• Presence of palatal budges.
• Angulated or flared laterals.
• Change colour of centerls or laterals .
C) Palpation and percussion :
• Palpation of the upper canines is a vital step in assessing the
• Deciduous canines or adjacent permanent teeth should be
checked for mobility, tenderness and vitality.
• The use of various techniques has been advocated for localization of impacted
I. Right Angle Technique (Broadway & Gould, 1960) - (Coupland, 1987).
II. Horizontal Parallax Technique “ SLOB Rule” (Clark, 1909) .
III. Vertical Parallax Technique (Richards 1952, Rayne 1969, Keur 1986).
IV. CT scans (Ericson & Kurol, 1987).
V. Cone Beam Computed Tomography (CBCT).
VI. The single panoramic radiograph .
Right Angle Technique & Tube Shift Technique :
1) Upper standard occlusal (midline view) and periapical (centered on
the canine region)
2) Tow periapicals (one centerd on the upper central incisor and the
other centered on the canine region )
The single panoramic radiograph
• Chaushu, Chaushu and Becker (1999) have
described a method of localizing maxillary canines
using only a panoramic radiograph.
•This depends on the fact that objects nearer the x-ray
source (and further from the film) project a larger
image than objects closer to the film and further
from the x-ray source.
• Thus palatal canines will appear larger than buccal
canines (remember that the x-ray source from a
panoramic radiograph comes from behind the head).
• In the coronal and middle thirds of the adjacent incisor, the ectopic canines that
were positioned buccally had a canine-incisor width ratio of 0.78-0.1.11 and the
palatal canines a canine-incisor width ratio of 1.5-1.7.
• While not an infallible method of localizing canines, this can be a useful adjunct to
other methods and may help to provide a positive diagnostic localization.
Relates to prognosis and complexity of aligning canine.
Therefore, the aim was to investigate which of the following radiographic factors might
influence the orthodontist decision to expose, and align or remove an impacted upper
I. Canine angulation to the midline
II. Antero-posterior position of the canine root apex
III. Vertical height of the canine crown
IV. Canine crown overlap to the adjacent incisor
Study by: N. Stivaros & N.A. Mandall 2000
Root resorption of maxillary lateral Incisors
12% of cases with impacted canines ,
CT studies show 48% of laterals demonstrate a degree of root resorption (Ericson and Kurol, 2000).
Walker 2004 used CBCT and showed 67%
• CT could be considered when resorption cannot be ruled
out from intra-oral films.
Risk factors for resorption of lateral roots:
- female, age <14yrs, horizontal palatal canines
- advanced canine root development
- canine crown medial to midline of lateral incisor
According to RCSEng 2016 Husain and McSherry
1 ) No active treatment/leave and observe
• Indications :
1. Patient does not want treatment
2. Canine very displaced, ie high and above roots of incisors
3. No evidence of resorption of adjacent teeth or other pathology
4. Ideally good contact between lateral incisor and first premolar wih
5. Good prognosis for the deciduous canine
Radiographic monitoring should take place to rule out cystic
formation (frequency unknown), migration, resorption etc
2) Interceptive treatment by extraction of the primary canine
• in carefully selected cases , where the ectopic permanent canine is not severely displaced ,
there is some evidence that interceptive extraction of the adjacent primary canine can result in
an improvement in position of an ectopic permanent canine.
• the patient should be aged between 10-13 years , with better results reported in the absence
of crowding .
• if radiographic examination reveals no improvement in the ectopic canines position 12
months after extraction of the primary canine , alternative treatment options should be
Ericson and Kurol : suggested that removal of the deciduous canine
before the age of 11 years will normalize the position of the
ectopically erupting permanent canines in 91% of the cases if the
canine crown is distal to the midline of the lateral incisor. On the
other hand, the success rate is only 64% if the canine crown is
mesial to the midline of the lateral incisor
Evidences of interceptive extraction of
3) Surgical exposure and orthodontic alignment
• The case is not suitable for interceptive treatment .
• The patient should be well motivated and have good dental health.
• The patient should be willing to wear fixed orthodontic appliance.
• The degree of malposition of the ectopic canine should not be so great that
orthodontic alignment is impractical .
• The success of treatment decreases with age in adults .
4) Surgical removal of the ectopic permanent canine
•If the patient declines active treatment .
• If there is radiographic evidence of early root resorption of the
adjacent incisor teeth .( but exposure and alignment of the ectopic
canine is usually indicated in cases where severe root resorption of an
incisor tooth has occurred necessitating the extraction of the incisor ).
• If there good contact between 2 and 4 “best result”.
• Where interception has failed and grossly malpositioned
• ideally with open apex at 13-14 yrs. to aid vitality.
• optimal development stage for auto transplantation is
when the root is 50-75% formed = half to three-quarters complete .
• The prognosis should be good for the canine tooth to be transplanted with no evidence
of ankylosis .
• The transplanted canine may require root canal therapy to be commenced within 10
days following transplantation.
II) Impacted maxillary central incisors:
Delayed eruption of the permanent maxillary incisor teeth can be considered in the
a. eruption of the contralateral incisor occurred more than 6 months earlier.
b. the maxillary incisors remain unerupted more than one year after the eruption
of the mandibular incisors.
c. There is a significant deviation from the normal eruption sequence (for
example, lateral incisors erupting prior to the central incisor).
Incidence : 0.13 %
the maxillary central incisor is the third-most commonly impacted tooth after
third permanent molars and maxillary canines.
Causes of delayed eruption
General causes :
o Hereditary gingival fibromatosis .
o down syndrome .
o Cleidocranial dystosis .
Localized causes :
o Crowding .
o Delayed exfoliation of primary tooth.
o Supernumerary tooth .
o Abnormal position of crypt .
Management of unerupted central incisors
• RCSeng recommandations (Yaqoob et al 2010):
III) Impacted lower second premolar
• The mandibular second premolar is one of the most frequently impacted teeth.
• The recommended treatment is to extract the second primary molar with or without removing
the bone along the eruption path, to uncover the tooth surgically and move it into the arch by
• . The prevalence of impacted premolars has been found to vary according to age . the overall
prevalence in adults has been reported to be 0.5%.
• Premolar impactions may be due to local factors such as mesial drift of teeth arising from
premature loss of primary molars; ectopic positioning of the developing premolar tooth buds;
or pathology such as inflammatory or dentigerous cyst.
• They may also be associated with over retained or infraocclusal ankylosed primary molars or
with syndromes such as cleidocranial dysostosis .
Management of infra-occluded primary second molars.
• Husain J, Burden D, McSherry P. Management of
the palatally ectopic maxillary canine. London: The
Royal College of Surgeons of England, Faculty of
Dental Surgery, 2010.
• Surgical and orthodontic management of
impacted maxillary canines .Vincent G. Kokich,
• Bishara SE. Impacted maxillary canines: a
review. Am J Orthod Dentofacial Orthoped
1992; 101: 159–171.
• Ericson S, Kurol J. Longitudinal study
and analysis of clinical supervision of
maxillary canine eruption. Community
Dent Oral Epidemiol 1986; 14: .
• Becker A, Chaushu S. Success rate and
duration of orthodontic treatment for
adult patients with palatally impacted
maxillary canines. Am J Orthod
Dentofacial Orthop 2003; Nov 124