IMPACTED MANDIBULAR THIRD MOLARS

IMPACTED MANDIBULAR THIRD MOLARS

Impacted mandibular third molars are classified on the basis if their position in the bone and relation to the adjoining tooth. 

1)Based on relation of tooth to ramus of the mandible and second molars:

Class 1 - where there is sufficient amount of space between ramus of mandible and distal surface of second molars to accommodate the mesio-distal diameter of crown of the third molar. 

Class 2 - The space between distal surface of second molar and ramus is less than mesio- distal diameter if the crown of third molar. 

Class 3 - when the third molar is located within the ramus of the mandible. 

2) Based on relative depth of third molar in the bone:

Position A-  when highest portion of the third molar is at the level of occlusal  line or above it. 

Position B-  when the highest portion of the tooth is below the occlusal line but above the cervical line of second molar. 

Position C- when the highest portion of the tooth is below the cervical line of the second molar. 

3) Based on position of long axis of impacted third molar in relation to long axis of second molar:

1) Vertical

2) Horizontal

3) Inverted

4) Mesioangular

5) Distoangular

6) Buccoangular

7) Linguoangular

8) Unusal position.


PRE-OPERATIVE ASSESSMENT OF THE IMPACTED MOLARS

It is required for proper treatment plan.
The diagnosis should be framed on the basis of history, clinical examination and radiological examination. The radiograph should be studied very carefully before planning a surgical procedure. The number, size  and curvature of roots should be studied. Classify the impaction that best fits into the classification. Study the relationship of roots to inferior dental canal. The exact position and depth of the tooth should be ascertained. Three imaginary lines are drawn for this purpose and are know as Winter's lines. 

White line

White line represent the line joining the buccal cusps of erupted molars and going posterior over the third molars region. The relationship to the white line will indicate the relative depth of the third molars.

Amber line

Runs at the level of the crest of interdental septum between the molars and represent the bone level covering the impacted tooth.

Red line

It is the line drawn perpendicular from the amber line to an imaginary point where the elevator will be applied. It indicates the amount of of resistance and difficulty encountered during removal of impacted third molars.