Mixed dentition space analysis in kodava population: a comparison of two methods.

AIMS To evaluate the reliability of Tanaka and Johnston and Moyer's (75th percentile) mixed dentition prediction methods in Kodava population sample, to formulate regression equations for predicting the mesiodistal widths of unerupted canines and premolars and to construct probability tables for the Kodava population. SETTINGS AND DESIGN Data was obtained from Kodava subjects visiting the clinics for routine dental check up. MATERIALS AND METHODS Dental models of 30 male and 30 female Kodava subjects (age range is 16 - 23 yr) were used. Teeth measured included mandibular permanent incisors, maxillary and mandibular permanent canines, first and second premolars. Digital caliper calibrated to 0.01mm was used to record mesiodistal dimensions. The actual teeth measurements were then statistically compared with the predicted values derived from the Tanaka and Johnston's equations and Moyers probability tables at the 75(th) percentile. STATISTICAL ANALYSIS USED Descriptive statistics including means, standard deviations were calculated for the actual and predicted tooth sizes. Student's t-tests were performed to compare the differences between the measured mesiodistal widths of canine, first and second premolars and the predicted values derived from Moyers. Correlation and regression analysis were performed to formulate standard regression equations. RESULTS Tanaka and Johnston prediction equations overestimated the mesiodistal widths of permanent canines and premolars in both the arches. Moyers 75(th) percentile also overestimated the actual measurements except for the maxillary arch in female subjects. The percentage of overestimation was more for Tanaka - Johnston prediction method than that of Moyers (75(th) percentile). Correlation and regression analysis were performed between the predicted and actual tooth size and standard regression equations were developed for the Kodava population. Probability tables were also constructed from the data obtained. CONCLUSION The data from present study illustrates the limitation of Tanaka and Johnston regression equations and Moyer's (75(th) percentile) chart when applied to Kodava population. From this data, regression equations and probability tables were derived for tooth size prediction for Kodava population. This would be more accurate when applied to local children of Kodava community.