Difficulty index of mandibular third molar (M3M) surgery in relation to mandibular second molar (M2M)
| Parameter | Score | |
|---|---|---|
| Spatial relationship with M2M1 | ||
| Mesioangular | Long axis of M3M parallel to M2M | 1 |
| Horizontal | Long axis of M3M perpendicular to M2M | 2 |
| Vertical | Long axis of M3M inclined in mesial direction to M2M | 3 |
| Distoangular | Long axis of M3M inclined in distal direction to M2M | 4 |
| Depth of impaction in relation to occlusal of M2M2 | ||
| Position A | Uppermost portion of M3M is located at or above OP of M2M | 1 |
| Position B | Uppermost portion of M3M is located between OP and cervical line of M2M | 2 |
| Position C | Uppermost portion of M3M is located below cervical line of M2M | 3 |
| Available space in relation between mandibular ramus and distal part of M2M2 | ||
| Class I | Sufficient space between MR and distal part of M2M for accommodation of the mesio-distal width of M3M | 1 |
| Class II | Not enough space between MR and distal part of M2M for accommodation of the mesio-distal width of M3M | 2 |
| Class III | All or most of M3M is in MR | 3 |
| Total score | 3 to 10 |
(OP: occlusal plane, MR: ramus of the mandible)
Total score of three parameters is categorized as follows: minimally difficult, 3-4; moderately difficult, 5-7; very difficult, 8-10.