A three-dimensional analysis method for edentulous mandibular ridge shape.

The aim of this study was to develop a three-dimensional method to analyze edentulous ridge shapes. A laser projection method was used to record the shape of edentulous plaster models. Contour of residual ridge on the reconstructed image was then subdivided into small triangles, and a 'normal line' representing the center of gravity of each triangle was determined buccolingually and anteroposteriorly. Angle between the normal line on the residual ridge and the tentative occlusal plane was calculated for each triangle. These angles were then used to analyze the ridge shape. This method was used to analyze the ridges of 20 edentulous patients with excessive bone resorption. The results suggested that this method was useful for analyzing edentulous ridges regardless of ridge shape and degree of resorption.