Effect of the short – term forward head posture correction for masseter muscle activity and temporomandibular joint function

The aim of the study: Determine the effect of short – term forward head posture correction for masseter muscle activity and temporomandibular joint (TMJ) function. Problem and hypothesis of study: Are many studies with significant results about connections between posture and stomatognathic system (Shousha et al., 2018). When head moves horizontally forward, tension of the muscle develops mandibular to retraction position (Danner et al., 2009). There is a lack of evidence how head posture correction changes stomatognathic system functions, that is why we did study to determine if a short – term head posture correction affects system. Methods of study: Evaluation of posture, TMJ range of motion, jaw opening stereotype, maximum bite force, electrical activity of masseter muscles. Research questions: Will short – term head posture correction affect the head inclination angle, TMJ amplitudes of active motion, jaw opening motion stereotype, electrical activity of masseter muscles, for individuals with upper cross syndrome. Results: After short – term head posture correction, head inclination angle alteration: Scapular R = 5,65°, Scapular L = 3,9°. Jaw opening amplitude alteration Scapular R 15,09 mm, Scapular L 15,58 mm. The difference between mandibular deviations decreased to Scapular R 1,60 mm; Scapular L 1,18 mm. Deviation during jaw opening reduce Scapular R 2,06 mm; Scapular L 2,38 mm Maximal bite force difference between sides increased Scapular R 4,27 kΩ; Scapular L 5,39 kΩ. There are no significant differences in the electrical activity of masseter muscles. Conclusions: Short – term head posture correction significantly reduce head inclination angle, mandibular opening movement amplitude and deviation from centerline, but no significant effect in the electrical activity of masseter muscles, in individuals with upper cross syndrome and asymmetric scapular position