Effect of Facial Asymmetry on Two-Dimensional and Three- Dimensional Cephalometric Measurements

Two dimensional (2D) lateral cephalometric analyses are used to measure the shape, size, position and orientation of the different facial units. These analyses are done on lateral cephalometric radiographs. In these radiographs, all the facial structures are projected onto a single sagittal plane. However, the information which can be gathered from them is limited. In determining position, the information is limited to the anteroposterior and vertical dimensions. In determining orientation, the data is limited to pitch. In determining size, the parameters are limited to length and height, while in determining shape the analysis is restricted to projections on the sagittal plane. In spite of all these limitations, clinicians have found lateral cephalometric analyses useful and have utilized them to study facial growth, to appraise facial deformities, to plan treatment, and to evaluate outcomes. The usefulness of these analyses arises from the fact that most individuals have facial symmetry. In this group of patients most of clinically relevant measurements can be determined from a lateral analysis. Nevertheless, as many as one third of patients with dentofacial deformities have facial asymmetries.1 Therefore, the effects of these types of deformities on 2D lateral cephalometric measurements needs to be established. Preliminary observations completed i