Pont’s index is an average measurement for a group, and although it can be applied to all group members, it must not be applied to the individual. Participants in the study (Navajo males and females, and dental students) had ideal occlusions with crowding or spacing of less than 1 mm. The measurements of the interarch widths of the maxillary premolars and first molars were compared with those calculated with use of Pont’s index. Differences between the measurements ranged from −12.5 to +9.8 mm for premolar widths, and from −15.1 to +14.7 mm for the molar widths. In most participants, the observed measurements were less than the calculated ones. Differences were found between arch forms in males and females with similar Pont indexes.