Métodos de previsão na análise da dentição mista: validação na população portuguesa

Abstract

Objectives: To verify if Moyers' probability tables at both 50th and 75th percentiles and the Tanaka-Johnston equations are reliable methods for the mixed dentition analysis applied to a Portuguese population sample. Methods: 58 study models were selected and mesio-distal measurements were performed on all teeth, 16 to 26 and 36 to 46. Statistical analysis was performed using Matlab and Excel programs. Results: Once applied the methods to evaluate the percentage of cases for deviation greater than 1. mm between predicted and real measurements, the method of Moyers at 50th percentile presents a total value of 29%, the Tanaka-Johnston 38% and Moyers at the 75th percentile, 45%. Moyers' method at the 50th percentile, presents for deviations greater than 1. mm, only in 12% of the cases by underestimation and 17% of the cases by overestimation.The method of Moyers at the 75th percentile and Tanaka-Johnston determine by underestimation the difference between predicted and real values by more than 1. mm in 3% of the sample. By other hand, for overestimation, the figures change to 42% and 35% respectively. Conclusions: From this study it can be concluded that mixed dentition analysis by Moyers' method at the 50th percentile, presents the lower number of cases where the difference between predicted and real values is greater than 1. mm. Therefore, Moyers' method at the 50th percentile appears as the most reliable method to be applied for this purpose in the analysis of the Portuguese population, when compared to the other two methods evaluated.