A method for identifying tooth regions. The method includes generating a first threshold image from a first tooth image by selecting intensity data values higher than a first predetermined threshold value c1; generating a second threshold image from a second tooth image by selecting intensity data values higher than a second predetermined threshold value c2; generating a preliminary tooth regions image that defines at least a first tooth region from the intersection of the first and second threshold images; generating a reference binary image from the first image by selecting intensity data values higher than a third predetermined threshold value c3, wherein threshold value c3 exceeds c1; and generating a refined tooth regions image from at least the first tooth region in the preliminary tooth regions image. The first tooth region is connected to objects in the reference binary image.