Mandibular Arch Form Analyses: a Comparison between Results of Two Different Methods

This study was conducted to determine the morphology of mandibular dental arch forms. Two different methods were used for this purpose and compared to find out the frequency distribution. It was conducted on 100 patients visiting Lahore Medical and Dental College, Lahore. Dental casts were photocopied and investigated to find out the square, tapering and ovoid arch forms. A mathematical model of arch form determination advocated by Noroozi and superimposition of orthoform templates were the two methods used. A comparison of frequency distribution for the results of two methods was carried out by applying “Chi square” test. Cross tabulation was done to study the congruence of the two methods on various arch forms. Frequency distribution of ovoid, square and tapering arch forms was 74%, 14%and 12% respectively by Noroozi’s mathematical model and 56%, 7% and 37% respectively by the orthoform templates. There was a noteworthy difference in frequency distribution of arch forms according to the two methods. The p-value (p <0.001) was statistically significant. However both methods showed ovoid arch form as the most prevalent in the sample.