Figure 1.

Standard model grouping. Group 1: The right maxillary central incisor as the abutment, with the remaining teeth complete; Group 2: The second left maxillary molar as the abutment, with the remaining teeth complete; Group 3: The first right maxillary premolar and first right maxillary molar as the abutment, with the missing second right maxillary premolar filled with wax, and the remaining teeth complete; Group 4: The right to left maxillary cuspid as the abutment, with the remaining teeth complete; Group 5: All of the right maxillary side teeth as the abutment, with the teeth on the left side complete; Group 6: All of the maxillary teeth as the abutment.