Remodeling dental anatomy vs sham therapy for chronic temporomandibular disorders. A placebo-controlled randomized clinical trial.

BACKGROUND: Evidence regarding the etiology or effective treatments for chronic orofacial pain, the majority diagnosed as temporomandibular disorder (TMD), is limited. PURPOSE: To investigate whether occlusal equilibration therapy (ET) and decreasing the (higher) angle of the lateral guidance on the nonworking-side leads to a reduction in chronic TMDs intensity. METHODS: It was conducted a randomized, explanatory, single blind with blinded assessment, placebo-controlled trial with strong protection against bias involving patients with chronic TMDs. Participants were randomly assigned to receive equilibration therapy or sham therapy. ET in this study consisted of minimal invasive occlusal remodeling to obtain balanced occlusion with reduction of the steeper angle of lateral mandibular movement with respect to the Frankfort plane. The primary outcome was a change in the pain intensity score (on a 0-10 point scale, with 0 indicating no pain and 10 the worst possible pain) at month 6. Secondary outcomes include maximum unassisted mouth opening and psychological distress. RESULTS: A total of 77 participants underwent randomization, 39 of whom received ET and 38 sham therapy. The trial was stopped early for efficacy, according to preestablished rules when 67 participants (n = 34, n = 33, respectively) had completed the analysis. At month 6, the mean unadjusted pain intensity score was 2.1 in the ET and 3.6 in the sham therapy group (adjusted mean difference, -1.54; 95% confidence interval [CI] -0.5 to -2.6; P = 0.004; ANCOVA model). The mean increase in maximum unassisted mouth opening (main secondary outcome) was significantly higher in the real therapy group (adjusted mean difference 3.1 mm, 95% CI 0.5-5.7, p = 0.02). CONCLUSION: ET significantly reduced the intensity of facial pain associated with chronic TMDs and increased maximum unassisted mouth opening, as compared with sham therapy, over the course of 6 months. There were no serious adverse events. Funded by the Instituto de Salud Carlos III from the Ministry of Science and Innovation of the Government of Spain and European Regional Development Fund, Grant nº PI11/02507; "una manera de hacer Europa".

Asymmetry of dental or joint anatomy or impaired chewing function contribute to chronic temporomandibular joint disorders.

INTRODUCTION: The etiologies of most chronic temporomandibular joint disorders are unknown. However, an association between habitual chewing on a particular side and chronic temporomandibular joint disorders has been reported. The aim of this study was to investigate the differences between sides (affected vs unaffected) of biodynamic factors (including lateral dental guidance determined by dental anatomy) or condylar path angles (determined by temporomandibular joint morphology) and chewing function (physiological alternate chewing vs single habitual chewing side). The study scope was to investigate possible etiological factors to improve the understanding of temporomandibular joint disorders. The null hypothesis was that no difference would be found between sides that are or are not affected by chronic temporomandibular joint disorders in chewing function or in levels of dental or temporomandibular joint remodeling. METHODS: This cross-sectional, double-blind study involved 24 adults with substantial, chronic, unilateral symptoms diagnosed as temporomandibular joint disorders. Chewing function, temporomandibular joint remodeling (using axiography) and dental anatomy (lateral guidance angles using kinesiography) were assessed. RESULTS: Habitual chewing on one particular side was observed in 17 of 24 participants; significantly more (n=15) chewed on the affected side than on the unaffected side (P=0.002 in a two-tailed Fisher's exact test; risk estimate=4.5; 95% CI 1.326-15.277). The condylar path (CP) angle was steeper on the affected side than on the unaffected side (mean (standard deviation)=50.52° (9.98°) versus 45.50° (7.98°); P=0.002 in a two-tailed t-test). The lateral guidance (LG) angles were flatter on the affected side in all 24 participants. CONCLUSION: Our results suggest that habitual chewing on one side may be associated with increasing condylar path, with flattening lateral guidance angles, and also with chronic temporomandibular joint disorder on the habitual chewing side.

Unilateral vicious mastication ­ The importance and resolution: A case report

Introduction: Patients presenting Temporomandibular Disorders (TMD) are common in our daily clinical practice. One of the possible conditions that lead to TMD is the habitual chewing side syndrome. Methods: In this case report a clinical approach is presented to manage the TMD related to unilateral vicious mastication. A 42 years old woman presented reporting headaches, difficulty to open mouth, presence of sensitivity in the left ear and TMJ region, soreness on the left side temporal region and sensitivity in the anterior inferior teeth. It was noted that the patient habitually clenched and ground teeth. Patient mentioned chew more on the left side. Results: After confirming the unilateral mastication, a modified therapy based on the Neuro occlusal Rehabilitation was applied through the use of a splint. After 60 days the patient described absence of the previous symptoms and pain relief. Conclusion: The evaluation of the masticatory pattern is often neglected; however, it is of great importance since it can lead to several conditions such as condyle wear, pain, alteration of the occlusal plane, deviation of the medial line, deviation of the mandible at mouth opening, bone alterations, Temporomandibular joint(TMJ) hypofunction, headache, among others.