Bruxism is a repetitive jaw muscle activity that occurs during sleep or while awake, characterized by teeth clenching or grinding. Bruxism affects millions of people worldwide and is considered one of the most harmful activities for the stomatognathic system due to its morphological, pathophysiological, psychosocial features and clinical consequences. Repetitive teeth clenching and grinding movements can cause spasms, stiffness, pain, and activity changes in the chewing muscles. Since bruxism is a disorder that depends on many variables, there is no single, specific treatment and multidisciplinary approaches are often required. Most treatment strategies are conservative and symptomatic, aiming to prevent the consequences of the disorder. The main purpose of physiotherapy techniques is to reduce the negative effects of bruxism on the chewing system. Physiotherapy techniques include exercises, manual therapy, electrotherapy, acupuncture, and posture awareness. It is not clear in the literature which physiotherapy techniques are effective in the management of bruxism; Therefore, more controlled studies need to be conducted. When studies in the literature are examined, no studies have been found that objectively investigate the effectiveness of relaxation techniques alone in people with muscle pain and increased muscle stiffness due to teeth clenching problems. Within the scope of this project, it is planned to investigate the effectiveness of the myofascial release technique (MGT) and post-isometric relaxation technique (PGT) using the grastone tool. MGT provides pain relief and functional recovery by creating a low load and long-term stretching effect on the myofascial structure. Post-isometric relaxation technique (PGT), a muscle energy technique, involves voluntary contraction in a precisely controlled direction against resistance. The results of this study will reveal the effects of MGT and PGT, which have different mechanisms of action, on muscle stiffness and pain in people with bruxism. In addition, by analyzing and presenting the data obtained, the gap in the current literature will be filled and it will contribute to becoming a component of the frequently used physiotherapy program in the management of bruxism. It is expected that patients' quality of life and productivity will increase depending on the relief of their symptoms. The study is a prospective, randomized, controlled, double-blind study. People with bruxism will be informed about the study and an informed consent form will be obtained. Participants' age, gender, body weight, height and Body Mass Index (BMI) will be evaluated and recorded with a specially prepared evaluation form. Individuals with bruxism between the ages of 18-65 who volunteer to participate in the study will be included. The study included patients with neurological, psychiatric, or systemic disease, dental treatment or physical therapy, using occlusal splints, being pregnant and having active cancer, having surgery planned for the relevant areas, having no more than two molars, using removable prostheses, and those using temporomandibular joint in the last three months. People receiving treatment will be excluded. Participants will be randomly divided into three groups. Participants will be assigned to the MGT group, PGT group, and Control group. In our study, MyotonPRO will be used to evaluate the stiffness of the sternocleidomastoid and masseter muscles of bruxism patients and the visual analog scale will be used to evaluate pain. All evaluations will be made by the same researcher before and immediately after the single-session intervention. No intervention will be made to the chin and cervical area before the first measurement. There will be a 2-minute break before the second evaluation begins.