Symptoms and prevalence of the temporomandibular disorders before and after orthognathic surgery

Aim: The aim of this study was to evaluate temporomandibular joint (TMJ) symptoms, the functional and neuromuscular changes after surgical-orthodontic treatment of orofacial deformities with temporomandibular dysfunction (TMD). Material and Methods: The study was based on a group of 400 dysgnathic patients. Were evaluated skeletal and dental malocclusion type, TMJ symptoms, headache, cervical and neck pain, otovestibular symptoms. Electromyography and kinesiography were used to assess the muscular activity and the mandibular movements. Results: TMJ symptoms in low and normal angle mandibular retrognatism patients have improved (p<0,01).The post-treatment results showed that almost all craniomandibular symptoms were significantly reduced postoperatively above all muscular spasms (93%) and headache (62%), (P<0.01); mandibular kinesology (84%) was improved (P<0,01). Also cervical pain, otovestibular and postural symptoms seem to benefit from treatment. Even if preoperatively asymptomatic, patients with TMJ problems after surgery (8,8%) have resulted (P<0.1). In preoperatively asymptomatic patients who developed TMJ symptoms after surgery, the highest incidence was found in high angle patients with severe mandibular retrognatism, treated by bimaxillary surgery. Conclusion: The combined surgical-orthodontic treatment may be of a great benefit in the correction of discrepanciesin occlusion and maxillo-mandibular relationship in the severe orofacial deformities associated to temporomandibular disorders. Conversely orthognathic surgery can produce TMJ symptoms by changing the position of the mandible and the maxilla with regard to each other and therefore the position of the condyle in the glenoid fossa. Mandibular ramus, osteotomies have a direct influence on this position, whilst in maxillary osteotomies the influence is indirect because of autorotation.