The function of the TM joint should be evaluated using a bilateral technique. Place the fingertips over the joint and have the patient open and close slowly (Figures 23 and 24), move the jaw to the left and right and jut the chin out.
Look for altered opening and closing pathways, abnormal sounds, tenderness and limitations in opening. There are two basic types of altered opening pathways, deviations and deflections. An altered pathway on opening which comes back to the midline at maximum opening is termed a deviation. If the greatest distance from the midline occurs at maximum opening it is called a deflection. Abnormal sounds may be heard or felt and usually fall into one or more of three major categories, clicks, pops and crepitus. Clicks and pops are associated with articular disk derangement and crepitus is usually associated with some form of arthritis. Correlate TM joint findings with the patient’s occlusal classification and other dental findings such as missing teeth and poorly fitting partial and/or full dentures. Follow-up questions should focus on the history of any observed symptoms and determination of any life style or dietary modifications the patient may have made to alleviate discomfort. Examination of the TM joint provides a perfect transition point for the intraoral examination.