Trismus

Trismus is the clinical term for restricted jaw opening caused by spasm of the muscles of mastication, particularly the masseter, temporalis, and medial pterygoid muscles. In dental practice, trismus most commonly presents as a post-operative complication following third molar extractions, especially impacted lower wisdom teeth. It can also result from prolonged dental appointments where the mouth is held open for extended periods, infections spreading into the fascial spaces adjacent to the jaw, trauma, radiation therapy to the head and neck region, or temporomandibular joint disorders.

The condition is clinically significant because it can interfere with oral hygiene, nutrition, and subsequent dental treatment. Normal maximum mouth opening ranges from approximately 35 to 55 millimeters, and trismus is generally diagnosed when interincisal opening falls below 35 millimeters. Mild cases typically resolve within one to two weeks with conservative management including warm compresses, gentle stretching exercises, soft diet, anti-inflammatory medications, and muscle relaxants. Severe or persistent cases may require referral for physical therapy or further investigation to rule out underlying pathology such as infection or neoplasm.

In day-to-day revenue cycle work, trismus creates billing considerations at multiple levels. The initial procedure that caused the complication should be well documented with pre-operative risk factors noted. Follow-up visits for managing trismus need appropriate evaluation and management codes, and any prescribed therapies or medications should be recorded. If the trismus delays planned treatment, such as restorative work or prosthetic impressions, the practice must track and reschedule these appointments. Thorough documentation protects the practice in the event of patient complaints or insurance inquiries about the frequency of post-operative visits.