Computer anchorage analysis of digitized picture of modified typodont.

In contemporary orthodontic treatment, the extraction of a premolar is frequently indicated, followed by canine retraction with bodily movement. The main problem is how to prevent the mesial movement of first molars (loss of anchorage) and loss of the space obtained by extraction. The aim of the study was to evaluate the anchorage capacity of posterior teeth using SW (straight wire) appliances after extraction of first premolars and to determine Goshgarian transpalatal arch as anchorage reinforcement. All experiments were recorded by video-camera, and the analogue signal has been digitized and saved on PC. Computer animation visualised the direction and the amount of tooth movement. Very significant loss of anchorage was found (in the control experiment), when molars and premolars were reinforced. No significant difference between the active and non-active transpalatal arch has been perceived in the sense of lateral anchorage stabilization.