Upper cervical spine abnormalities as a radiographic index in the diagnosis and treatment of temporomandibular disorders

Objective: The aim of this study was to investigate the clinical characteristics and treatment outcomes of patients with temporomandibular disorders (TMD) according to the presence of upper cervical spine abnormalities and craniofacial morphology. Study Design: Clinical examinations were conducted on 43 patients with TMD. Upper cervical spine characteristics (fusion, posterior arch deficiency [PAD], and craniofacial morphology) reflecting head-and-neck posture were evaluated on lateral cephalograms. Condylar bone changes in the temporomandibular joint were evaluated by using cone beam computed tomography. Clinical characteristics and treatment outcomes after 1 year of conservative therapy were statistically analyzed between groups, according to the presence of upper cervical spine abnormalities. Results: Pain on neck muscle palpation was more frequent in patients with cervical fusion (P = .019) and with either fusion or PAD (P = .004) before treatment. Patients with PAD had smaller comfortable mouth opening ranges compared with those without the deficiency (P = .044) before treatment and smaller comfortable (P = .020) and maximum (P = .021) mouth opening ranges after treatment. Patients with PAD also had mouth opening limitation (P = .028) and pain on masticatory muscle palpation (P = .014) more frequently after treatment compared with patients without the deficiency. Conclusions: Associations exist between upper cervical spine characteristics and treatment outcomes in patients with TMD, suggesting such parameters as a possible radiographic index in TMD diagnosis and treatment.