Abstract: A normal vector or a curvature at each of a plurality of vertexes that are included in data relating to an oral cavity shape including a tooth crown shape of at least one tooth and define the oral cavity shape is acquired. Then, a vertex group that defines the tooth crown shape of the at least one tooth is extracted from the plurality of vertexes based on the acquired normal vectors or curvatures. Further, the extracted vertex group is outputted as tooth crown shape information that specifies a tooth crown portion in the oral cavity shape. Consequently, automatic construction of a database for a tooth crown shape can be implemented.

Abstract: A normal vector or a curvature at each of a plurality of vertexes that are included in data relating to an oral cavity shape including a tooth crown shape of at least one tooth and define the oral cavity shape is acquired. Then, a vertex group that defines the tooth crown shape of the at least one tooth is extracted from the plurality of vertexes based on the acquired normal vectors or curvatures. Further, the extracted vertex group is outputted as tooth crown shape information that specifies a tooth crown portion in the oral cavity shape. Consequently, automatic construction of a database for a tooth crown shape can be implemented.

Abstract: A movable table positioned to a predetermined position with respect to a base through manual movement, fixed to the base after the positioning. A lift mechanism that releases a top plate from a fixed state and lifts the top plate from the base against an attraction force of a magnet, or against the attraction force and the gravity of the magnet, and a mechanism that lowers the top plate from a predetermined lifted position with either or both the attraction force or the gravity of the magnet, and fixes the top plate to the base with an action of the attraction force of the magnet.