The purpose of the present study is to compare the experimental and clinical results of permanent and removable appliances on headgears. 3 dymentional photo-elastic models were used in the experimental work. On these models, forces applied to face bows which were attached to permanent and removable ancher units. After the experiment sagittal sections prepared and analised under polariscope. The results of the 8 case with removable ancher units and 7 case with permanent ancher units were compared by sephalometric processes. As a result, there was no significant difference between permanent and removable headgears.

Keywords: Permanent And Removable Headgears, Distalisations of Upper First Molar Teeth, Method Of Fotoelasticity