Résumé
This study determines and compares the frequency distribution and results of two methods establishing morphology of the dental arch form. It was conducted on 250 patients visiting Lahore Medical and Dental College, Lahore. The casts were measured and photocopied, which were analyzed first by using a mathematical model as advocated by Noroozi3 and then by superimposing orthoform templates to determine the arch forms. The dental arches were classified into square, ovoid, and tapered forms to determine and compare the frequency distributions between the two methods. The comparison between results of both methods was made by applying chi square test. Cross tabulation was done to observe the congruence of two methods on different arch forms. According to Noroozi's mathematical model, frequency distribution of ovoid, square and tapering arch forms was found to be 82%, 64%and 11.2% respectively while according to orthoform templates those were 53.2%, 9.2% and 37.6% respectively. There was a statistically significant difference between results of two methods [P<.001]. The ovoid arch form was most common arch form according to both methods. There was a statistically significant difference in the results of two methods as well as their frequency distribution