Improvement of anterior disc displacement on the mandibular deviated side after intraoral vertical ramus osteotomy in a patient with facial asymmetry: a case report

Purpose: We present the orthognathic treatment of an adult skeletal Class III patient with facial asymmetry, mandibular rightward deviation, and anterior disc displacement without reduction (ADDwoR) at the right temporomandibular joint (TMJ) by intraoral vertical ramus osteotomy (IVRO).
Materials and methods: The patient was a 23-year-old man with complaints of mandibular deviation and crowded lower anterior teeth, resulting in facial asymmetry. The maxillary position was normal with protrusion and rightward deviation of the mandible. There was no cant of the maxilla. He experienced pain in the right TMJ during mastication, and Magnetic resonance imaging (MRI) revealed an ADDwoR on the right side. The patient was diagnosed with Class III malocclusion, skeletal Class III prognathism with mandibular deviation, and ADDwoR on the right side. Orthognathic surgery was proposed for jaw deformity, and IVRO was performed to correct mandibular deviation.
Results: One year and 2 months after treatment onset, IVRO was performed with differential setback: 2 mm on the right and 8 mm on the left side of the mandible. The midline of the lower dentition was rotated by 6 mm to coincide with the facial midline. Symptoms of temporomandibular disorders were not observed post-operatively. Active-treatment period was for 31 months. MRI findings showed improvement in anterior disc displacement on the right side during the post-retention.
Conclusion: In the case of facial asymmetry with anterior disc displacement on the mandibular deviated side, IVRO was suggested to have a potential effect on the positional relationship between the mandibular head and temporomandibular disc.