occlusal splint therapy of temporomandibular disorders

Abstract

Introduction

Temporomandibular joint disorder (TMD) is a term covering acute or chronic inflammation of the temporomandibular joint, which connects the mandible to the skull. Since tissue adaptation seems to play a major role in the natural course of TMD, treatment should be oriented toward promoting a joint condition that is most likely to repair or adapt. The individually fabricated and adjusted occlusal stabilization splint is one of the most commonly advocated devices for treatment of signs and symptoms of TMD. However, their mechanism of action or the precise conditions underlying the final therapeutic effect are largely unknown. The effectiveness of stabilization splint therapy in reducing symptoms in patients with TMD is controversial. The aim of this review is to put together and evaluate the mechanism of occlusal stabilization splint therapy in reducing symptoms in patients with TMD.

Main discourse

The effectiveness of occlusal splint therapy in reducing symptoms in patients with pain dysfunction syndrome is evaluated. Occlusal splint therapy was compared to: acupuncture, bite plates, biofeedback/stress management, visual feedback, relaxation, jaw exercises, non-occluding appliance and minimal/no treatment. There is weak evidence to suggest that the use of SS for the treatment of PDS may be beneficial for reducing pain severity, at rest and on palpation, when compared to no treatment. There is insufficient evidence either for or against the use of occlusal splint therapy for the treatment of temporomandibular pain dysfunction syndrome. Establishing mechanism of occlusal splints helps to support using occlusal splint as therapeutic tools. The effect of splint on muscle is 1) muscle activity change 2) changing of postural activity of mandible and body (trunk and cervical muscle included) 3) establishing balance by reduction muscle asymmetry. Occlusal splints are a means of reversibly altering the occlusion to reduce masticatory muscle activity. Occlusal splint with equal-intensity contacts on all of the teeth, with immediate disclusion of all posterior teeth by the anterior teeth and condylar guidance in all movements, will relax the elevator and positioning muscles. The neuromuscular harmony that follows provides optimal function and predictability to the system. Insertion of occlusal splint changes muscle activity, symmetry, VD and occlusion. All of these changes are co-related and have an impact on postural balance. Occusal splint changes not only masticatory muscle including masseter muscle, but also whole body postural muscles, in turns it influence on postural activity. However, the articles that have no control group and low grade evidence level like case report are insufficient to show clear relevance between occlusal splint and postural activity change. Many studies concerning postural activity change by occlusal splint can be unreliable and outdated. Temporomandibular joints are susceptible to overload. Splints reduce stress on condyle by 1)distracting TMJ 2) free movement on new postural position without interference. Most of studies compared condyle/fossa changes before and after occlusal splint therapy. It is researched with X-ray radiography, MRI image, axis indicator, intra articular pressure measurement. The mechanism to improve symptom is splints had an impact on condyle/disc complex. However, that is not valid conclusion but still hypothesis because it is hard to see 3-dimentional position of condyle with these measurement tools. Some studies demonstrated occlusal splint changes disc: disc position, mobility, strength. However, most of them are non-controlled study and had a limitation with their evidence level. Occlusal splints have therapeutic effect by reduction occlusion force, occlusal interference, occlusion duration, occlusal contact area and stabilization of occlusal contact. The flat surface of the occlusal splint facilitates mechanically the action of clenching lateral movements (eccentric bruxism) and in turn modifies and/or reduces the duration of the episodes of muscle activity. The occlusal splint provides smooth pathways for mandibular excursions, and prevents the mandible locking laterally, beyond the interocclusal relationship during the eccentric bruxism. Clenching and grinding (trauma) in such an extreme lateral position, can harm the masticatory system, especially in the joint region. Pain reduction produced by splints is associated with reduction in parafunctional activity.

Conclusion

Occlusal Splints do not heal patients; they give patients the opportunity to heal themselves There is sufficient credible literature to support the use of splint therapy to reinstitute neuromuscular harmony in a compromised masticatory system. Occlusal splint therapy has better long-term results in reducing the symptoms of TMD. In this review, there are many hypotheses concerning occlusal splint mechanism and more well-controlled studies are needed. However, occlusal splint has better patient compliance, fewer side effects, and is more cost-effective than other therapeutic modalities; hence, it can be chosen for the treatment of patients with TMD.