Which complication following an inferior alveolar nerve block injection is least likely to occur?

Infection following an inferior alveolar nerve block (IANB) is the least likely complication. The most common complications of IANB are trismus (due to hematoma formation in the medial pterygoid or trauma to muscle fibers), hematoma (from inadvertent puncture of the inferior alveolar vessels), and ecchymosis (bruising from blood tracking into soft tissues). True infection is rare because the oral mucosa is punctured with a sterile disposable needle in an area that naturally hosts bacteria, but the body's defenses typically prevent infection unless there is an immunocompromised state or significant bacterial inoculation.