A Study Of Bolton's And Pont's Analysis On Permanent Dentition Of Nepalese

Objective: The purpose of this study was to establish a normative standard of overall tooth size ratio (OR) and anterior tooth size ratio (AR) for Nepalese population by performing Bolton's analysis and to see if there is gender difference in OR and AR and also to compare Nepalese OR and AR with the Bolton's OR and AR for Caucasian and OR and AR value of Chinese.Next purpose was to find the reliability of Pont's index and also to study whether there is any relation between sum of maxillary incisors and the arch width in premolar area and molar area for Nepalese.Methods: Sample contained 100 Nepalese subjects, male and female in almost equal ratio (51 male and 49 female), age ranged from 14 to 24 years. All subjects were with individual normal occlusion with molar and canine class I relationship. Statistical analysis was performed to calculate mean, standard deviation, coefficient of correlation, independent t-test, one sample t-test of Bolton's OR and AR for Nepalese. The percentage of population outside Bolton 2 standard deviation was also been calculated. The tooth size ratios obtained for Nepalese were compared to the Bolton's standard and also compared with mean overall and anterior ratio for Chinese. Mesio-distal tooth size measurement, arch width measurement in premolar area and, molar area was performed. All the measurements were done with vernier caliper. Coefficient of correlation was calculated to find the reliability of Pont's analysis for prediction of arch width and also to find the correlation between sum of incisors and arch width.Results: The normative value on mean overall ratio (OR) for Nepalese is found 91.22% with a standard deviation of 1.99 and the mean anterior ratio (AR) 78.04% with standard deviation of 2.72. No significant difference was found between Nepalese male and female in OR and AR. No significant difference was found in OR between Nepalese and Bolton's for Caucasians as well as Nepalese and Chinese. The AR for Nepalese was larger than Bolton's standards and smaller than Chinese normal mean value. For Nepalese the frequency of tooth size discrepancy the Overall ratio outside 2 standard deviation of Bolton overall ratio was 4% (outside -2 SD were 2% and outside +2 SD were 2%) where as anterior ratio outside 2 standard deviation of Bolton anterior ratio was 15% (outside -2SD was 6% and outside + 2 SD was 9%).The correlation coefficient between the measured arch width values and the corresponding calculated values according to Pont's indices were low in all cases with r values ranging from 0.07 to 0.29.Conclusions:1. The normative standard of OR for Nepalese is similar to that obtained by Bolton for Caucasian and that of Chinese, but the normative standard of AR obtained for Nepalese is significantly different than that obtained by Bolton for Caucasian and also that of Chinese.2. There is no significant difference found between Nepalese male and female in OR and AR.3. Pont's index is not reliable for predetermination of ideal arch width values for Nepalese male and female.