Measurements will be made before and after intervention to assess the effect of anterior deprogrammer application on the tone of the selected masticatory muscles and condyles position in mandibular fossa. The first group (control) will be counsel with an explanation of the pathomechanism of masticatory muscles pain and preventive principles. In the second group, the Sliding Guide will be used for a period of 12-15 minutes, in the third Dawson B-Splint for 7 days, and in the fourth Kois deprogrammer for 14 days. Devices in group 3 and 4 will be used by patients for 24 hours a day, with breaks for oral hygiene procedures and eating/drinking.