The study group will consist of 100 women (GI) aged 20 to 45 who report pain and increased facial muscle tension in masseter muscles.~The diagnosis will be made according to RDC/TMD (Research Diagnostic Criteria for Temporomandibular Disorders), which will determine the occurrence of painful myofascial disorders. Patients will undergo both external and intraoral dental examinations to exclude odontogenic and articular causes of pain. Patients will then be palpated for the masseter muscles and both: the range of mandibular abduction (linear measurement in mm) and the level of pain intensity (VAS scale).~The control group (GII) will consist of 100 women between 20 and 45 years of age with no signs of masticatory disorders or orofacial pain during a physical examination and with no such reference in their medical records.~In order to obtain a homogenic study group the following inclusion criteria will be applied:~Myofascial pain of less than 12 months in duration that is evoked by an active motion of the mandible or by palpation.~A feeling of an increased muscle tension~Presence of all occlusal contact zones~Female sex~Exclusion criteria:~Past or present, neurological disease, neuromuscular disease or severe systemic disease.~Temporomandibular joint pathology based on X-ray imaging or stomatological examination.~Orthodontic or prosthetic treatment~Contraindication to physiotherapeutic treatment~Patients with a stomatognathic system disorder will be randomized into four therapeutic subgroups, 26 patients each, who will receive a physiotherapy treatment of the masseter muscles for a period of 10 days (excluding Saturdays and Sundays). The duration of a single therapy session will be 12 minutes per patient in each of the subgroups.~The division of the study group into subgroups is as follows:~IA: magnetotherapy; a pulsating, non-homogeneous magnetic field generated by the Viofor JPS apparatus (Med & Life, Poland) will be applied with an elliptical applicator with a beamwidth of approx. 5 cm.~IB: magneto-led therapy; synergistic action of a slowly changing magnetic field generated by the Viofor JPS apparatus (Med & Life, Poland) and LED diodes with the wavelength of 860 nm will be applied with an elliptic magnetic-light (IR) applicator with a diameter of 5 [cm] containing 47 infrared diodes.~IC: magneto-laser therapy; synergistic action of a slowly changing magnetic field generated by the Viofor JPS apparatus (Med & Life, Poland) and a low-energy laser with an infrared wavelength of 808 [nm] (max. power 300 mW) will be applied. The dose would increase from 3,0 J/cm2 to 5,0 J/cm2 and the total dose applied per each patient from this subgroup was 40 J/cm2.~ID: manual therapy of soft tissues (i.e. post-isometric relaxation of the masseter, cellular and tissue mobilization with Kibler fold, masseter trigger point therapy).~Immediately after the therapy, the patients' pain level will be assessed via VAS scale. After the last day of physiotherapy, a linear measurement of mandibular abduction will be performed.
The study will determinate influence of four selected physiotherapeutic procedures on the pain intensity and the range of mandibular mobility in patients with myofascial disorders in the SS.