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. ...