1. Method for the geometrical analysis of scan data (D) from oral structures, comprising the steps of selecting a number of parameterized tooth models (M) of desired tooth types according to the scan data (D) to be analyzed, whereby the parameterization is performed on the basis of model parameters comprising position parameters and/or shape parameters and line parameters, and whereby each tooth model (M) comprises at least one boundary line (LS, LP) whose path is defined by line parameters and which divides a tooth model (M) in at least one active adjustment area (AA) and at least one inactive adjustment area (AI), adjusting the tooth models (M) and their boundary lines (LS, LP) to the scan data (D) for individualization, whereby the individualization is performed by variation of model parameters, and whereby the active adjustment areas (AA) of the tooth models (M) are weighted more than the inactive adjustment areas (AI), segmenting the scan data (D) on the basis of the individualized tooth models (M) and their individualized boundary lines (LS, LP) and/or determining at least one boundary line (LS, LP) in the scan data (D).