Dr. Chun-Lin Su
Attending Surgeon
Topic
Orthognathic Surgery
Posnick Chapter 9: Temporomandibular Disorders: Effects of Occlusion, Orthodontic Treatment, and Orthognathic Surgery
Temporomandibular disorders (TMDs) affect the temporomandibular joint, masticatory muscles, and related craniofacial structures. Although TMD signs and symptoms are common, many cases improve spontaneously. Current evidence indicates that TMD has a multifactorial origin, with occlusion playing only a limited role. Certain occlusal features, such as open bite, excessive overjet, CR–CO discrepancy, posterior crossbite, and loss of posterior support, may be associated with TMD, but none reliably predicts disease. Orthodontic treatment does not appear to increase TMD risk. Orthognathic surgery may improve preexisting symptoms, but should not be performed solely to treat TMD; conservative, reversible management remains preferred.