Three-dimensional analysis of changes in location of crowns and root apices of maxillary central incisors.

A method has been described for analyzing the direction and extent of movement of root apices and midpoints of the incisal edges of maxillary central incisors. The system permits a detailed examination of the effectiveness of any orthodontic technique in relocating maxillary incisors and is particularly useful in determining the efficacy of "torquing" mechanisms.