Changes in tooth size-arch length relationships from the deciduous to the permanent dentition: a longitudinal study

The purpose of this investigation is to determine the changes in the maxillary and mandibular tooth size-arch length relationship (TSALD) after the complete eruption of the deciduous dentition (mean age = 4.0 years) to the time of eruption of the second molars (mean age = 13.3 years). In addition, an attempt was made to determine whether TSALD in the permanent dentition can be predicted in the deciduous dentition. Records on 35 male and 27 female subjects were evaluated. Each subject had a clinically acceptable occlusion--that is, a normal molar and canine relationship, at the time of eruption of the deciduous and permanent teeth. In addition, each subject had a complete set of data at the two stages of dental development. These selection criteria limited the number of subjects in this investigation to 62. The mesiodistal diameter of all deciduous teeth and their permanent successors, as well as various dental arch width and length parameters, were measured in the deciduous and permanent dentitions. A total of 68 parameters were measured or calculated. Student t tests were used to determine whether significant differences were present between the right and left sides for both male and female subjects. Correlation coefficients r were performed between the deciduous and the corresponding permanent teeth and also for the arch length parameters, as well as TSALD in the two dentitions. Significance was predetermined at the 0.05 level of confidence. Stepwise regression analysis (R2) was used to determine which of the variables in the deciduous dentition could be included in a regression model to determine associations between maxillary and mandibular TSALD in the permanent dentition.(ABSTRACT TRUNCATED AT 250 WORDS)