Comparison of two non-radiographic techniques of mixed dentition space analysis and evaluation of their reliability for Bengali population

CONTEXT: Mixed dentition arch analysis system is an important criterion in determining the type of orthodontic treatment plan. Different mixed dentition arch analysis system are available and among them both Moyer's and Tanaka-Jhonson method of space analysis was developed for North American children. Anthropological study reveals that tooth size varies among different ethnicities The present study was performed to determine the reliability of Moyer's and Tanaka-Jhonson's method of mixed dentition arch analysis system among Bengali population. AIMS: To perform the comparative evaluation of the two mixed dentition space analysis system among Bengali population. MATERIALS AND METHODS: Dental casts of maxillary and mandibular arches of 70 Bengali children with permanent dentitions were fabricated. The mesiodistal crown dimensions of all erupted permanent incisors, canines, and premolars were measured with digital callipers. For particular sum of mandibular incisors, Moyer's and Tanaka-Jhonson's mixed dentition arch analysis were calculated and further statistical analysis was carried on. STATISTICAL ANALYSIS USED: Descriptive statistics including the mean, standard deviation, and minimum and maximum values, unpaired‘t’ tests, correlation coefficient “r” were calculated and tabulated. RESULTS: Tanaka and Johnston regression equations under-estimated the mesiodistal widths of permanent canines and premolars. On the other hand, there were no statistically significant differences between actual mesiodistal widths of canines and premolars and the predicted widths from Moyers charts at the 50% level for the lower and upper arches, among Bengali population. CONCLUSIONS: The study suggested that both Moyer's and Tanaka-Jhonson's mixed dentition arch analysis are applicable in Bengali population but with little modification in their regression equation.