Occlusal-surface shape data and occlusal-surface position data of dentures are acquired on a dentist side, and the data is then transmitted to a grinding data provider side. A maxillomandibular occlusal state data is reproduced from the occlusal-surface shape data and the occlusal-surface position data on the grinding data provider side. A maxillomandibular occlusal adjustment portion is determined by changing a maxillomandibular occlusal vertical dimension by the grinding data provider side. Cutting data including the occlusal adjustment portion data and the occlusal-surface position data are prepared on the grinding data provider side, and the data is transmitted to the dentist side. An occlusal adjustment is carried out by cutting the dentures by a grinding machine based on cutting data on the dentist side.
