A 65-year-old male with a myocardial infarction one year ago, coronary artery disease, and Type 2 diabetes presents for extraction of tooth #18 with buccal swelling and purulent drainage. He takes aspirin 81 mg, lovastatin, and metformin. Which complication following an inferior alveolar nerve block (IANB) injection is LEAST likely to occur?

Correct answer: A. Infection

• A. CORRECT — LEAST likely. Infection as a complication of an IANB injection is extremely rare. The oral mucosa is naturally colonized by bacteria, but the aseptic technique used during injections and the vascularity of the area make infection following a standard nerve block uncommon. It is the least commonly listed complication of local anesthetic injections.
• B. INCORRECT (trismus IS a recognized complication). Trismus (limited mouth opening) can occur after an IANB due to trauma to the medial pterygoid muscle from multiple injections, intramuscular bleeding/hematoma, or infection. It is a well-documented complication.
• C. INCORRECT (hematoma IS a recognized complication). Hematoma can occur from inadvertent puncture of the pterygoid venous plexus or inferior alveolar vessels during an IANB. This is an established complication.
• D. INCORRECT (ecchymosis IS a recognized complication). Ecchymosis (bruising) from extravasated blood following vascular puncture is a recognized, though typically minor, complication of IANB.