Mixed dentition space analysis in Egyptian children

This study was done to examine the applicability of the Tanaka and Johnston and Moyers’ methods of prediction in Egyptian population and to develop a new prediction method for this specific population if necessary. A total of 325 Egyptian students 145 female, 180 male, mean age 14.4 years, SD±1.1 years were randomly selected from 10 preparatory and secondary schools in Mansoura city, Dakahlia governorate, Egypt during the academic year 2008–2009. The mesiodistal crown diameters of the permanent teeth were measured and compared with the predicted values derived from the Tanaka and Johnston's equations and from Moyers’ probability tables at 35%, 50% and 75%. Significant sexual dimorphism was found in tooth sizes. There were significant differences between the actual measurements and that derived from the Tanaka and Johnston's equation and Moyers’ tables. New linear regression equations were derived for both genders to allow accurate tooth size prediction in Egyptians. The correlation coefficients between the total mesiodistal width of the mandibular permanent incisors and that of the maxillary and mandibular canines and premolars were found to be 0.78 and 0.89 in male and 0.63 and 0.87 in female, respectively. It can be concluded that there is a limitation in the application of the Tanaka and Johnston's and Moyers’ prediction methods to Egyptian population. The developed prediction equation is more accurate for predicting the mesiodistal widths of unerupted canine and premolars of Egyptian population.