Introducing a New Cephalometric Analysis Technique by Studying the Natural Age Changes of the Soft Tissue Facial Profile: The Stable Cartesian Coordinate System [SCCS] Analysis

Abstract

SUMMARY: The most common method used to analyze lateral cephalograms involves plotting the landmarks and then studying the angles and distances between them. This paper introduces a new analysis technique and use it to examine the natural age changes of the soft tissue facial profile. Cephalograms from the same subjects at three time periods were analyzed: ages 20s, 30s, and 40s. None of the subjects received orthodontic treatment prior or during the observation period. The landmarks were analyzed using the new SCCS analysis to obtain landmark specific horizontal and vertical displacement information. Data was collected for each landmark in terms of x- and y-coordinates. The results show that the age related changes correspond well with previous studies done in this area which used the standard method. Additionally, the results indicate that ageing is not a gradual process, but occurs in bouts. This ageing bout takes place about 10 years earlier for the female, however when it does occur in males the changes are more numerous and of greater magnitude. The SCCS analysis gives more detailed landmark specific information. It allows for a mathematically accurate, real-world scale, visual representation of the average facial profile. Also, superimposition is no longer necessary. Finally, a method was designed to take advantage of the positive aspects of the standard method and the SCCS analysis simultaneously.