Temporomandibular Disorders are a common clinical picture that appear in particular in people between the age of 20 and 40 years. About 33% of the total population shows symptoms and signs of TMD. Among the temporomandibular joint disorders anterior disc displacement appear to be the most common. In case of limitations of jaw movements and or pain conservative methods including combinations of behavior change, physiotherapy, stabilization appliance therapy and medication are most popular. The benefit of a self-treatment program to strengthen the lateral pterygoid muscle and to learn a properly executed lower jaw sideways movement to achieve pain reduction is up to now not well investigated. The aim of this study is to examine the effectiveness of muscle training for the treatment of patients with anterior disc displacement with reduction (DDWR). 60 patients with DDWR and pain (≥18 years) will be randomly allocated to two groups: 1. Physical exercises, 2. Stabilization appliance therapy. All patients receive a functional examination according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) at baseline. The training in group 1 includes eccentric and concentric counter-movements of the lower jaw muscle to strengthen and restore a physiological lateral movement of the mandible. The muscle exercises should be performed once a day with 5-6 repetitions per side. The treatment with an equilibration appliance in the lower jaw serves as a comparison group. Patients are instructed to wear the appliance while sleeping. The wearing rhythm is described as intermittent. (three nights - wearing the appliance, one night - not wearing the appliance). The primary target variable is the occurrence of pain in the head and joint area before and during therapy. The variable is measured using a numeric rating scale (NRS; 0-10) during the baseline examination and control check-ups after 2, 4 and 6 months.