Aim: To investigate the association between mid-line deviation of the mandible, as determined by upper to lower labial frena, and signs and symptoms of Temporomandibular Disorders (TMDs). Materials and Methods: The current study was original research conducted on a sample of 439 medical records of TMD patients treated at Tufts University. All patients underwent a clinical examination revealed a detailed information regarding temporomandibular joints, history of pain, and comprehensive intra-oral findings. Subjects were divided into three groups: 1. No frenal deviation, 2. Deviation to the right, and 3. Deviation to the left. Results: Signs and symptoms of TMD tend to occur more likely on the side of the frenum deviation. The signs and symptoms that were significantly associated to frenum position were TMJ crepitation sounds and locking, right muscles pain on palpation (medial pterygoid and sternocleidomastoid), and “reported locking on the left TMJ”. Subjects with aligned frena showed a statistically significant increase in the range of motion to the right side. The results also revealed a highly significant association between maxillary plane canting and mandibular frenum position. Left posterior cross bite was significantly more prevalent in the left frenum deviation group. Conclusion: Expression of TMD signs and symptoms was more prevalent on the side of frenum deviation. TMD population showed a higher prevalence of left mandibular frenum deviation. Several signs and symptoms were significantly associated to frenum position.


TMD, Labial frenum, Frenum deviation