Objective: The objective of this study was to determine quantitatively the wear resistance of a newly developed light-curing resin for two different types of occlusal splints over a period in situ of six months. Materials and Methods: The study included two samples of ten patients each that had been provided with either stabilization or distraction splints. These occlusal splints were repositioned on remount casts and the occlusal aspect was surveyed prior to insertion and at the four-week, three-month, and six-month recalls. The test setup consisted of an anti-vibration table framework, three translation stages, an inductive displacement transducer, a stereomicroscope, and a digital measurement unit for data acquisition and analysis. The coordinates for the occlusal contacts were stored at the baseline examinations and reproducibly sought out during the recall examinations. Each examination included ten repeat measurements each in the regions of teeth 13, 23, 16, and 26. Results: After six months, the stabilization splints showed a median vertical gain of 1 µm in the region of tooth 13 and a median vertical loss of 24 µm in the region of tooth 23. Regions 16 and 26 exhibited median vertical losses of 37 µm and 33 µm, respectively. In the second sample (distraction splint), the corresponding vertical loss values were 1 µm (tooth 13), 23 µm (tooth 23), 33 µm (tooth 16), and 64 µm (tooth 26). Statistical analysis (Mann-Whitney U-test, p Conclusions: The present study clinically confirms the good wear resistance results of the new resin splint material obtained in a previous in-vitro study [Ottl et al., Dtsch Zahnärztl Z 52, 342 (1997)]. This parameter is of great importance for maintaining the therapeutic mandibular position during the treatment period. Keywords: craniomandibular disorders, temporomandibular joint, clinical follow-up study, occlusal splint therapy, resin, wear resistance