Occlusal splints (MORA) vs. placebos show no difference in strength in symptomatic subjects: double blind/cross-over...

Many athletes with or without occlusal problems are now using mandibular orthopedic repositioning appliances (MORA) or simply occlusal splints, supposedly to enhance skeletal muscle strength. Recent research to establish these claims has suffered from design inaccuracies. In theory, the MORA reduces temporomandibular stress during clenched jaw efforts. It is suggested that pain in the temporomandibular joint (TMJ) and surrounding musculature could limit a maximum effort during an athletic endeavour. Eight subjects with TMJ disorders were tested for strength changes in 4 muscle groups with a custom MORA and placebo splint in a tightly controlled double-blind cross-over protocol using a Cybex II dynamometer. A two-way analysis of variance (ANOVA) did not show significant differences in strength change between the two splints. Neither were there any trends that would suggest strength benefits from the MORA.