CANINES AND ECTOPIC TEETH (17)

Question 1

What is an impacted tooth?

Answer 1

An impacted tooth, which may be unerupted or partially erupted, is one that fails to achieve a normal, functional position.
This may be due to lack of space, obstruction by another tooth or bone or an abnormal path of eruption

Question 2

Sequelae of canine ectopia?

Answer 2

1. Root resorption (RR) of U2s will have RR when U3s are ectopic and unerupted
2. Coronal resorption
3. Cystic change (Low risk)

Question 3

What is the Aetiology of ectopic teeth ? Why some teeth have abnormal position ?

Answer 3

1: Generalized (genetic disorders)

2: localized:
- Hypodontia
- Tooth size : arch length discrepancies
- Prolonged retention or early loss of the deciduous canine
- Peg lateral incisor
- Odontomes
- Supernumerary teeth
- Ankylosis
- Alveolar cleft
- Cysts or neoplastic

Question 4

Assessment of Ectopic or unerupted teeth?

Answer 4

1. Clinical examination:
   - Asymmetric presentation
   - Absence of the bulge or presence of palatal bulge
   - Delayed eruption of permanent canines or prolonged retention of primary teeth
   - Splaying of lateral incisors
2. Radiographs (2 Horizontal parallax PA’s “more reliable”, Vertical parallax anterior occlusal or OPT)

Question 5

why to use radiographs to assess the ectopic teeth?

Answer 5

• To locate the impacted canine
• To investigate associated pathology
• To evaluate resorption of the involved teeth
  To choose appropriate treatment

Question 6

Treatment options for ectopic canines (or any other ectopic tooth)?

Answer 6

1. No Treatment
2. Interceptive treatment by extraction of the deciduous canine
3. Surgical exposure and orthodontic alignment
4. Extraction of impacted canine and orthodontic movement of a first premolar to close the space
5. Auto-transplantation
6. Prosthetic replacement

Question 7

Surgical exposure and Orthodontic alignment:

what are the 2 types of surgical exposure?

Answer 7

1.. Palatal surgical exposure:
- Raise a flap (Palatal flap +/- Buccal flap), then remove the overlying bone and follicle to the ADJ using Chisel&Mallet but not beyond the ADJ to avoid damaging the root cementum

2.. Labial surgical exposure

Question 8

what is Vertical rule of thirds?

Answer 8

Horizontal line drawn along cervical margin, along middle 1/3 of root, along apical 1/3 of root. So, Ectopic canines closer to the apical 1/3 are difficult to be mobilised into position (canines higher up aren’t ideal for mobilisation)

Question 9

what is Horizontal rule of thirds?

Answer 9

If the canines are closer to the midline they are not suitable for mobilisation.