Transverse development of the jaws: norms for the posteroanterior cephalometric analysis.

Norms available for the posteroanterior (PA) cephalometric analysis yield different information. The material used to generate these standards is not clearly defined. The purpose of this study was to use data from the Bolton-Brush Growth Study to generate new norms for the PA analysis. The Bolton material is recognized as a controlled longitudinal record of growing children. The assumption that growth in the transverse dimension is the first to be completed is challenged by finding that increments in maxillary and mandibular width vary, like sagittal and vertical growth, according to gender and chronologic age.