Impacted canines Flashcards
Impacted tooth : definition
Tooth that is prevented
from eruption due to obstruction of fibrous tissue, other teeth or bone
Prevalence:
U3’s =2%
L 3’s = 0.35%
Unilateral : Bilateral 4:1
Female : Male 70:30
Resorption U 1 and 2
due to impacted 3’s = 0.7%
Congenital absence U3’s= 0.3%
L3’s=0.1%
Guidance theory:
Canines are guided in eruption by the distal roots of the U 2’s.
They have a long path of eruption
Short rooted or absent U 2’s - increase in the incidence of palatally displaced 3’s
6% of impacted 3’s have small lateral incisors
Genetic theory:
- Greater prevalence in Europe than other racial groups
- More common in Females
- Familial occurrence
- Occurs in association with other anomalies ( hypodontia, transposition, variation in tooth size, ectopic position of other teeth, infra-occluded teeth)
- Polygenetic inheritance of U 3’s that are palatally displaced
Aetiology:
Genetic theory
Guidance theory
Displacement of the tooth cript Crowding - The main cause of buccal canine impaction 85%. Retention of deciduous canines Analysis Trauma Pathology
When do upper canines start to develop?
Start developing at 4-5 month old
Development of canines?
- commence high in the maxilla
- start to develop at 4-5 months
- crown calcification 6-7 yrs
- Migrate forward and downwards to lie buccal and mesial to the apex of U C’s before erupting down the distal aspect of U 2’s.
Last anterior tooth to erupt
Pressure from erupted canines on roots of laterals can cause incisors to flare
Eruption dates for Upper and lower canines?
Eruption:
U = 11-12 yrs
L = 10-11 yrs
How do you do a clinical assessment for impacted canines?
Visual examination = blanching or swelling
Palpation= buccal sulcus and palatally
Inclination of the lateral incisors
Vitality + Mobility of U2’s and U c’s
What radiographers you might take to check for impacted canines and why?
OPG Upper occlusal 3d CBCT, Parallax SLOB + BAPS To asses : - location of canine crown and root - prognosis - presence of resorption on Incisors - if c's present we can check the roots of c's
Associations of impacted canines?
Anomalies of tooth size and number: Class II div 2 incisors Small or developmental absent lateral incisor Crowding Resorption Hereditary
Talk about resorption due to impacted canines?
Unerupted / impacted 3’s can cause resorption of lateral incisor roots
Incisors resorption more common in Female
Angulation of an ectopic canine to the midline on an OPG is greater than 25 degrees = risk increases 50%
Proceeds at a rapid rate
Identifiable on rads
Intervention is needed quickly
Interceptive treatment for impacted canines?
- Palpate for unerupted canine around 9yr.
- Early detection of abnormal eruption path
- Extraction of c’s may result in improvement of position - allow normal eruption to occur- reduce the degree of displacement.
Important to locate position before extractions
Normal development: slightly distal to U 2’s root – good prognosis for extraction
E+B may be required
Talk about transposition: definition, prevalence, and treatment
Interchange in position of 2 teeth
Aetiology not fully understood. But appears to be genetic link with tooth size/number
Rare
F=M
U 3’s and 4’s most common
Lower 2’s and 3’s most common
Treatment: Position of the root is important
- Acceptance
- Xla of most displaced
- orthodontic treatment
Management of buccal displaced impacted canines?
More likely to erupt due to the buccal mucosa being thinner
Associated with crowding
- relive crowding prior to eruption usually leads to spontaneous improvement.
- Space should always be maintained if C’s are extracted
- If severely displaced = xla is required
- orthodontic treatment on extraction or non-extraction basis,
- surgical exposure ( apically repositioned flap to preserve the attached gingivae)
