The post-isometric relaxation techniques were administered to the mandibular adductors and muscles responsible for lateral movements of the mandible.

The myofascial release procedure was performed successively in the area of the anterior parts of the temporal muscles, the superficial parts of the masseter muscles and the sternocleidomastoid muscles.

1: Therapist (T) abducted the patients' (P) mandible until the functional barrier. P performed isometric tension of the mandibular adductors with about 20% of the maximum force, balanced by the T. After 10 secs of isometric tension, P relaxed his muscles, and T abducted the mandible to a new functional barrier. During one treatment, the cycle was repeated 3 times, each time starting from the previously obtained barrier.

2: T performed passive lateral translation of the mandible until the functional barrier. P performed isometric tension with about 20% of maximum force, as to initiate the movement of the mandible towards the resting position. T balanced the force generated by the P. After 10 secs of isometric tension, P relaxed his muscles and T deepened the lateral movement of the mandible until a new functional barrier was reached. During one treatment, the cycle was repeated 3 times, both to the right and left side, each time starting from the previously obtained barrier.

The electrical activity of the anterior part of the temporal and masseter muscles was assessed by surface electromyography (sEMG). The assessment was performed using a two-channel device - NeuroTrac MyoPlus 4 (Verity Medical Ltd.) and surface electrodes (Noraxon inc.). Examination of the same muscles on the right and left sides of the body was performed at the same time. The muscle tone of the anterior part of the temporal muscles was assessed first, followed by the masseter muscles. The parameter describing the degree of electrical activity of the muscle was the mean value of the thirty-second sEMG measurement.

Assessment of the intensity of spontaneous pain in the masticatory muscles The intensity of spontaneous pain in the masticatory muscles was assessed on the basis of a 10-point visual analogue scale(VAS).This scale included 11 pain grades- from 0 to 10,where 0 was no pain at all, 5 was moderate pain, and 10 was the strongest pain imaginable.