Temporomandibular joint disorders (TMJD) are frequent in patients with dentofacial deformities. Orthognathic surgery aims to restore occlusion, facial aesthetics and function, but its effects on TMD and quality of life (QoL) remain controversial. This study aimed to evaluate the evolution of TMJD-related clinical findings after orthognathic surgery and to assess their impact on QoL.

This prospective multicenter study included 192 patients undergoing first-time orthognathic surgery in France (2022–2024). TMJD-related symptoms (pain, joint noise and locking), maximal mouth opening (MMO), and self-reported bruxism were assessed preoperatively and at 4–6 weeks postoperatively. QoL was measured with the Orthognathic QoL Questionnaire (OQLQ) before surgery and at 8–12 months.

Preoperatively, 45.8% of patients presented with TMJD symptoms. Postoperatively, this prevalence decreased to 29.7% (p = 0.001), with significant reductions in joint clicking, noise, and deviated mouth opening, while joint pain remained unchanged. We observed a non-significant decrease in the prevalence of joint pain from the preoperative to the postoperative period. MMO transiently decreased after surgery (4.2 cm vs 3.0 cm, p < 0.0001). OQLQ scores improved significantly (31.8 ± 20.1 vs 15.4 ± 15.8; p < 0.0001), particularly in social and aesthetic domains. Patients with Class III malocclusion showed greater functional gains. The presence of TMJD was associated with lower preoperative QoL, and postoperative bruxism remained strongly correlated with poorer outcomes.

Orthognathic surgery contributes to significant improvement in TMJD mechanical symptoms and QoL. Comprehensive management, especially of parafunctions such as bruxism, is crucial to optimize long-term outcomes.