A new method of predicting mandibular length increment on the basis of cervical vertebrae.

The purpose of this study was to establish an equation to predict incremental mandibular length on the basis of the analysis of the cervical vertebrae in a single cephalometric radiograph and to compare the predictive accuracy with other methods. Data comprised two groups of 23 Japanese girls between CVMS I and CVMS V. Group A was examined to construct the predication equation. Group B served to compare the predictive accuracy with the growth potential method and the growth percentage method. The following results were obtained: (1) an equation was determined to obtain mandibular length increments on the basis of the measurements in the third and fourth cervical vertebral bodies, and (2) the average error between the predicted increment and the actual increment was 1.5 mm for the equation method, 2.4 mm for the growth potential method, and 2.8 mm for the growth percentage method. These results suggest that with the use of cervical vertebral measurements, it may be possible to evaluate the mandibular growth potential.