The purpose of this study was to investigate and evaluate what proportion is the characteristics in Korean dental arches with normal occlusion. Many others have already indicated Golden proportion in normal dental arches, but have not considered any racial and sociocultural differences. So the author postulated (√2)n relations in Koreans. The materials were consisted of 134 dental casts with normal occlusion, which have never undergone orthodontic and prosthodontic procedures. Measurements were made on the arch dimensions using sliding caliper and data were computerized. The findings were as follows: 1. The width between the distal surfaces of the upper centrals, had (√2)³ relation with the width between the buccal surfaces of the upper 1st premolars in Koreans. 2. The width between the distal surfaces of the lower laterals had (√2) relation with the width between the distal surfaces of the lower canines, and had (√2)² relation with the distal surfaces of the upper centrals. 3. The width between the distal surfaces of the lower centrals had (√2)² relation with the width between the distal surfaces of the lower laterals, and had (√2)³ relation with the width between the distal surfaces of the upper centrals.
