Correlations between mandibular asymmetries and temporomandibular disorders (TMD).

INTRODUCTION: Mandibular asymmetries are the fulcrum of many debates among modern orthodontists and maxillofacial surgeons. The interest is even greater when facial asymmetries are correlated to the development of TMJ symptoms and temporomandibular disorders (TMD).

OBJECTIVE: The aim of this study is to investigate how mandibular asymmetries constitute etiological or predisposing factors for the development of temporomandibular disorders (TMD). We considered patients with mandibular asymmetries associated with TMD. Using orthodontic or surgical-orthodontic treatment, patients experienced correction of their TMJ symptoms. Thus, mandibular asymmetries represent a major risk factor for the development of TMD.

MATERIAL AND METHODS: We studied a sample of 16 subjects aged between 14 and 36-years-old (11 females and 5 males) with mandibular asymmetries (81% structural asymmetry, 19% functional asymmetry). These subjects presented skeletal and dental malocclusions combined with several temporomandibular disorders, mostly due to muscle tension. In 100% of cases, patients received orthodontic treatment. We compared pre- and post-treatment postero-anterior (PA) cephalometric analyses in order to evaluate asymmetry resolution.

RESULTS: Comparison of measurements from pre- and post-therapy PA cephalograms showed resolution of mandibular asymmetries after treatment. The treatment resolved mandibular asymmetries and completely eliminated temporomandibular symptoms.

CONCLUSIONS: Orthodontic treatment of patients presenting mandibular asymmetry enables correction of all TMJ symptoms and TMD. Mandibular symmetries can therefore be considered to constitute etiological or predisposing factors for the development of TMD.