Abstract
The relationship between the eruption of succedaneous teeth, such as mandibular lateral teeth, and the factors contributing to their eruption was investigated statistically.
The materials were the serial 45° oblique cephalograms obtained from 20boys ranging from 3.8 years to 12.3 years of age. The variables used in this study were chronologic age, the amount of the eruption and formation of permanent canine, first premolar and second premolar, the amount of the root resorption of the deciduous canine, first molar and second molar, the amount of mandibular development. Based on the measurements, the product-moment correlation coefficients, partial correlation coefficients where the chronologic age was fixed, and the coefficient of determination between these variables by multiple regression analysis were calculated.
As a result, the partial correlation coefficients which eliminated the influence of chronological age indicated that the amount of root resorption of deciduous teeth and the eruption of succedaneous teeth revealed the highest correlation. The amount of root resorption of the predecessors was, therefore, found to be one of the important factors which could assess the amount of the eruption of succedaneous teeth.
Furthermore, multiple regression analysis was performed with the amount of eruption as a dependent variable and the amount of tooth formation, chronologic age, the square of the age, the cube of the age, the amount of root resorption of the deciduous teeth, and the amount of mandibular development as independent variables.
As a result, compared to the study by Kindaichi who made the polinominal regression analysis between two variables, a slightly higher coefficient of determination was obtained in the present study.
Eventually, it was found that the eruption of succedaneous teeth could be expressed as the combination of various contributing factors.
