Position and anatomical landmarks
Infiltration is carried out with the patient in the supine position with the head in a slightly backward flexion position. The head is positioned in the midline.
In adult patients, the second bicuspid tooth is located and the mental foramen palpated and marked. The distance between the mental foramen and the midline is about 2.5cm (see figure).
The surrounding area is disinfected and covered with sterile drapes. A needle (22-G) is inserted perpendicularly (under ultrasound guidance) just medial to the mental foramen until there is contact with bone. The location of the nerve is confirmed when the patient experiences paresthesia in the chin. The needle is slightly withdrawn and bupivacaine 0.25% with 20 mg of methylprednisolone is injected (in 2 ml).
- The most serious complication of the injection is infection.
- Small subcutaneous bleedings may result in a temporary increase in pain after the injection.