INBDE (Integrated National Board Dental Examination) Practice Exam

In which TMD condition do you deviate toward one side and then return to midline at max opening?

1. Disc displacement with reduction

2. Deviation

3. Deflection

4. Ankylosis

The correct answer is: Deviation

During the process of opening the mouth, the temporomandibular (TMJ) joint involves a combination of rotational and translational movements. In cases of deviation, the temporomandibular joint may not be functioning properly, causing the condyle (part of the mandible or lower jaw) to deviate to one side. This deviation often results in an asymmetric opening of the jaw, with the movement deviating to one side and returning to midline at maximum opening. In contrast, disc displacement with reduction (A) is a specific TMD condition in which the condyle deviates during opening, but also returns to its correct position during closing when the disc is repositioned onto the condyle. Deflection (C) is a general term used to describe any deviations in jaw movement, while ankylosis (D) is a serious condition in which the jaw joint becomes fused and movement is limited. Therefore, the most appropriate answer is B, deviation, as it accurately describes the condition described in the question.