Avoiding the mental foramen during periapical surgery

By Moiseiwitsch JR

Date: 02/1996
Journal: JOE

  Purpose:

Presents several techniques to decrease the risk of an un-favorable outcome following periapical surgery in proximity to the mental foramen.

Summary:

3 stages of the endodontic surgery, during which, the risk of mental nerve damage decreases which are: -Preoperative Dx, flap design, and flap retraction.

Preoperative Dx:

A PA radiograph vertically placed with a paralleling device is advised rather than PA only (Fig.1). OPG is considered, although, it’s associated with magnification and blurring artifacts.

-Flap design:

If surgery is indicated in a tooth posterior to the mental foramen a distal releasing incision is opted instead of the standard mesial releasing incision. The rational is to protect the mental nerve form retraction. Caution is advised to not injure the inferior labial branch of the facial artery although it can only occur if the incision is extended to the buccal vestibule. Injury to  the long buccal nerve is unlikely as it pierces the buccal fat pad anterior to the ramus of the mandible. The major part of reflection is inferior rather than mesial or distal, placing the releasing incision distally improves visualization and access.

-Surgical technique:

If nerve damage occur during surgery it is usually by stretching or crushing of the neurovascular bundle with the retractor. Although stretching may be avoided by the flap design. crush injuries are often caused by impinging the retractor against the base of the flap in which the mental nerve is contained. It is easy for the retractor to slip against the base of the flap. This problem may be avoided by grooving the bone at the approximate level of the apex, but coronal to the mental foramen (Fig.2).

Conclusion:

It is important to offer the most predictably successful result from endodontic surgical procedures.