The masticatory system is a complex entity, with its important functions of mastication, swallowing and speech that interfere in everyday life. It consists of the upper and the lower jaw, temporomandibular joints, masticatory muscles, teeth in occlusal relationships and associated support structures. Occlusion is a term which relates to mutual contacts of opposing teeth during mandibular movement. It includes static and dynamic occlusal relations. Temporomandibular disorders are a common group of symptoms that affect the masticatory system. Their etiology is not completely understood, but it is considered that there are five main groups of causes, including the state of occlusion. Previous research has shown that static occlusal relations do not affect the symptoms of temporomandibual disorders. Dynamic occlusal relations affect the occurrence of temporomandibular disorder symptoms through orthopedic stability and sudden or acute changes of occlusal state. Treatment of occlusal relations that can cause temporomandibular disorder symptoms is in the scope of dental practice. It can be divided into two groups: reversible and irreversible. Irreversible treatment can include occlusal adjustment, orthodontic repositioning, restorative and surgical procedures or a combination of different methods. Reversible treatment is carried out by means of occlusal splints, and it can be applied both as an initial treatment and a diagnostic method for assessment whether the occlusal state caused symptoms, and as a final treatment.