Incisal and Dental Archwidths ? Norms and Ratios

In the present study, one hundred sets of study casts of normal occlusion were obtained from Hyderabad population (50 males and 50 females) with age ranging from 13 to 18 years. The mesiodistal widths of incisors, the inter canine, inter premolar and inter molar widths of maxillary and mandibular arches were measured. The means and S.D.were calculated. Though the mean values in males were slightly more than in females, the differences were not statistically significant. The width ratios between upper and lower arches were calculated and these ratios were constant and stable statistically. Applying these norms clinically, it was possible to evaluate dental arch width, to locate the discrepancy in posterior crossbites and to plan treatment accordingly.