Effects of myocentric vs. manual methods of jaw position recording in occlusal splint therapy - a pilot study

Occlusal splint therapy is a central element of the treatment of temporomandibular disorders (TMD). However, little has been reported about the effect of transcutaneous electrical nerve stimulation (TENS)-based methods of myocentric jaw position recording on the effect of splint therapy. In this randomized clinical trial, 40 patients with myofascial pain of the jaw muscles were treated with occlusal splints fabricated using bimanual manipulation (Michigan group, n = 20) or myocentric jaw position recording (myocentric group, n = 20) for determination of centric vs. myocentric relation. Therapeutic effects were evaluated based on the change in pain symptoms and the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) procedure after 4 and 12 weeks of treatment. The extent of change in mandibular position was determined by condymeter measurements and magnetic kinesiography as well as by comparison with a healthy control group. Twelve weeks of wearing the respective splints at night resulted in the significant relief of symptoms in both groups, as determined based on subjective pain reports and visual analog scale (VAS) scores. Group comparison revealed that the VAS scores were significantly lower in the myocentric group. Myocentric positioning of the mandible led to mandibular position changes of similar extent in TMD patients and healthy controls. The use of TENS to establish myocentric relation for splint therapy is therapeutically effective and achieves a greater reduction in pain. Furthermore, TENS treatment alone also has a significant pain-relieving effect. Keywords: condylar position, jaw relation, Michigan splint, myocentric relation, occlusal splint, positioning, pain reduction, treatment effect