Sleep-related breathing disorders (SBAS) are one of the most common causes of non-restorative sleep. Sleep therapy options include positive pressure ventilation with continuous positive airway pressure (CPAP) masks, mandibular advancement of the mandible with mandibular advancement devices (MAD), back restraining, weight reduction, ear, nose and throat surgical procedures, bimaxillary or mandibular remodeling osteotomies, and neurostimulation procedures N. hypoglossal. In mild to moderate obstructive sleep apnea syndrome (OSAS), MAD, back suppression and weight reduction are potential treatment options. This study aims to identify possible side effects in the temporomandibular system that occur during nocturnal support of a mandibular arch over two years. Two different MADs are compared in terms of construction, height (bite elevation) and protrusion mechanics: the H-MAD with an hinge system according to Herbst and the SomnoDent Fusion ™ MAD (called F-MAD) with sliding side wings. In addition, it is to be evaluated whether hinge system according to Herbst as a protrusion-controlling element and the reduction of the splint body for a reduced bite elevation leads to a significant reduction of side effects compared to the F-MAD.