Changes of the condylar position after modified disk repositioning: A retrospective study based on magnetic resonance imaging.

OBJECTIVE: This study aimed to explain the malocclusion resulting from the changes in condylar position after unilateral open disk repositioning surgery. STUDY DESIGN: Patients treated with unilaterally modified temporomandibular joint disk repositioning were reviewed. All patients underwent magnetic resonance imaging (MRI) before and immediately after surgery. Occlusion was checked, and the changes in the joint space and condylar position were measured by using MRI. The paired t test was used for analysis. RESULTS: Thirty-two patients were included in the final analysis. The incidence rates of the posterior open bite in the affected side were 100%, 87.5%, 71.9%, 9.4%, 3.1%, and 3.1% at 0, 3, and 7 days and 3 and 6 months, and at the last follow-up after surgery, respectively. Mean distances of the condylar movements were 2.67 and 0.32 mm in the affected joints and normal joints, respectively. There were significant differences for the anterior (P = .03), superior (P < .001), and posterior (P < .001) joint spaces of the affected joints as demonstrated by MRI. CONCLUSIONS: The joint spaces significantly increased postoperatively, in addition to the changes in condylar position in anterior and inferior movements, leading to posterior open bite; however, the position returns to normal 3 months after surgery. We concluded that disk repositioning, when done unilaterally, results in stable occlusion over time.