Predicting Treatment Success Of The Functional Therapy in Class II Division 1 Patients

Abstract

Objective: The aim of this study was to determine the cephalometric variables that can predict the treatment success of Twin Block appliance in patients with skeletal class II divison 1 malocclusion.

Materials and Methods: The patients who were treated with the Twin Block appliance were recruited from the archive of the clinic. They were divided into 2 groups as success and failure according to the change in ANB angle. By the 6th month after treatment, patients with a change in ANB angle of 3º or more were included in the success group (14 patients; 7 females, 7 males). Patients with a change of 1º or less were included in the failure group (14 patients; 5 females, 9 males). Seventy-five variables were measured on the pre-treatment lateral cephalograms and the groups were compared. For each variable that showed a statistically significant difference between the two groups, the percentage of correct classifications was calculated.

Results: Of the seventy-five variables, fifteen showed a statistically significant difference between the two groups (p < 0.05). The percentages of correct classification ability of the variables varied between 82% and 57%. The variables with the highest classification success were as follows: Pg-NB (mm) (82.1%), U1NA (°) (78.6%), and L1-NB (mm) (75%).

Conclusions: The variables with the highest predictive ability showed that patients with a prominent chin tip, protrusive upper incisors and retrusive lower incisors were more likely to be successfully treated with Twin Block appliance.