Clinical evaluation of the technique of electrical neurostimulation of the masticatory muscles as a stage of deprogramming in the orthopedic treatment of patients with partial adentia complicated by temporomandibular joint dysfunction

Background. In the early stages of temporomandibular joint (TMJ) dysfunction, the disorders are functional in nature and are often associated with changes in occlusion. In response, compensatory contraction of the masticatory muscles occurs, and unilateral overstretching of the fibres is one of the factors that provokes the onset of pain symptoms in the TMJ and can cause dislocation (subluxation) of the intra-articular disc. Accurate determination and registration of the central relationship of the jaws remains the cornerstone of orthopedic treatment, especially in the presence of TMJ disorders complications. Deprogramming of the masticatory muscles for such patients is mandatory, which undoubtedly improves the functional quality of prosthetic treatment. Purpose – to evaluate the effectiveness of the method of deprogramming the masticatory muscles by means of their electro-neurostimulation with low-frequency impulse currents at the stage of determining and registering the central jaw relationship in orthopedic treatment of patients with musculo-articular dysfunction of the TMJ. Materials and Methods. This study involved 61 patients (45 women and 16 men) aged 28 to 68 years who had orthopedic treatment over a period of 5 years and had been diagnosed with partial secondary adentia complicated by musculo-articular dysfunction of the TMJ. All patients had a preliminary questionnaire, a standard dental examination protocol, and an additional thorough examination of the TMJ for an objective diagnosis. During orthopedic treatment, at the stage of determining and registering the central jaw relationship, a technique was used to deprogram the masticatory muscles by means of their electro-neurostimulation with lowfrequency impulse currents. In accordance with the established physiological position of the central jaw relationship, an occlusal splint was made and indicated for use until prosthetics. The statistical analysis of the results obtained was performed using the Statistica13.0 software package. The significance of the differences between the indicators before and after the procedure using the method we proposed was determined using the t-test. Results. Based on the results of the questionnaire, medical history and clinical examination, the main clinical symptoms of this dysfunctional condition were identified. The use of the muscle relaxation technique we propose allows for the elimination of muscle spasms in the masticatory and cervical muscles through their complete and deep relaxation. Therefore, it allows the elimination of restrictions in myofascial structures and is based on the use of neurophysiological inhibition mechanisms that help reduce muscle tension immediately after their isometric contraction. The selected pulse shape in the proposed method corresponds to the pulse shape in nerve fibres, and the limits of other parameters correspond to their generalised parameters. Accordingly, this series of pulses makes it possible to erase pathologically altered muscle function and restore the natural position of the jaws. Conclusions. Studies conducted at the clinic have shown that individually selected electro-neurostimulation modes lead to a massage effect and anti-contracture relaxation, reduce increased tension in the anterior temporal and masticatory muscles, lead to muscle relaxation, and restore the correct relationship between the teeth of the upper and lower jaws. Improved microcirculation in the areas of influence, in turn, leads to improved oxygen supply to soft tissues, has an anti-oedema effect, and additionally activates metabolic processes at the cellular level. The proposed technique allows for the accurate determination of the correct position of the central jaw relationship, which is crucial for effective orthopedic treatment of patients, especially when complicated by TMJ dysfunction, and also reduces the time required for the use of an occlusal splint.