Cephalometric markers to consider in the treatment of Class II Division 1 malocclusion with the bionator

The principal aims of this study were to find the cephalometric predictors for good treatment results of bionator therapy and to justify bionator ther apy as an early phase I treatment for patients with Class II Division 1 mal occlusion. Forty subjects who had Class II Division 1 malocclusion and who were treated with the bionator were selected for this study. They were clas sified into a good treatment result group and a poor treatment result group in reference to the posttreatment molar relationship, posttreatment overbi te and overjet, posttreatment profile, and existence of relapse. Thirty-one cephalometric variables were analyzed on the pretreatment lateral cephalog rams by t-test to evaluate differences between the 2 groups. The variables that differed significantly were analyzed by discriminant analysis to asses s their predictability. The study showed that horizontal growth pattern, cl ose to normal anteroposterior relationship between the maxilla and mandible , upright mandibular incisor, and retrusive lower lip were important predic tors for good results. In particular protrusion-of the lower lip was the mo st important factor for the determination of the treatment results. In addi tion, the treatment times were much shorter for patients with these good pr edictors. The present study supports the premise that bionator therapy can produce clinically stable and favorable results if the patients are appropr iately selected with the use of these diagnostic criteria.