A Cephalometric Analysis Comparing Incremental Skeletal Growth in the Adolescent Face with Projected Growth

Abstract

This study investigated the correlation between predicted growth in cranial base, maxilla, and mandible and the actual growth in these structures over a two-year period. The treatment sample consisted of 13 males and 16 females who prior to orthodontic treatment had a Class I skeletal relationship and an Angle Class I arch length discrepancy. The developmental age varied from 11.0 to 17.0 years of age in males and from 9.5 to 15.0 years of age in females. The control group of 14 males and 16 females had Class I skeletal patterns and Angle Class I occlusions. All subjects were Caucasians. To determine the actual growth values for the treatment sample, a standardized technique was used for taking two lateral cephalometric headplates: one at the beginning of orthodontic treatment and another approximately two years later. A wristplate was also taken from which the developmental age of each subject was determined. Two year growth prediction increments were calculated for each structure in the treatment sample based on the individual's developmental age. These prediction increments represent the average growth of the corresponding structure in the control sample. With the exception of the female mandible, when the predicted growth increments were compared to actual growth, the correlation coefficients were not large enough to justify using mean growth values as predictors of individual craniofacial growth. It was concluded that the individual variation in growth rate precludes the use of a group statistic, such as a mean increment, for predicting facial changes.