Efficiency of 1-phase and 2-phase treatment protocols in Class II, division 1 malocclusions

Rodrigo Hermont CANÇADO, Arnaldo PINZAN, Guilherme JANSON, José Fernando Castanha HENRIQUES, Leniana Santos NEVES, Conceição Eunice CANUTO

Aim: The purpose of this study was to compare the occlusal outcomes and the eficiency of 1-phase and 2-phase treatment protocols in Class II, division 1 malocclusions. Treatment eficiency was deined as a better dentoalveolar result in a shorter treatment time. Methods: Class II, division 1 subjects (n = 139) were divided into two groups in agreement with the treatment protocol adopted for Class II correction. Group 1 comprised 78 patients treated with 1-phase treatment protocol (single-stage group) at initial and inal mean ages of 12.51 (± 1.28) and 14.68 (± 1.49) years. Group 2 comprised 61 patients treated with 2-phase treatment protocol (two-stage group) at initial and inal mean ages of 11.21 (± 1.21) and 14.70 (± 1.55) years. Lateral cephalometric radiographs were taken at the pretreatment stage to evaluate morphological differences among treatment groups. Evaluations were performed on the initial and inal study models of the patients using treatment priority index (TPI). Chi-square tests were used to compare the two groups regarding initial molar Class and gender distribution. Variables regarding occlusal results were compared using independent t-tests. Finally, a multiple linear regression analysis was completed, with total treatment time as the dependent variable to identify clinical factors that predict treatment length for patients with Class II malocclusions. Results: Results demonstrated that similar occlusal outcomes are obtained between 1-phase and 2-phase treatment protocols, but the duration of treatment was signiicantly smaller in the 1-phase treatment protocol group. Conclusion: Based on the results of this investigation, it can be concluded that treatment of Class II, division 1 malocclusions is more eficient with the 1-phase treatment protocol.

Keywords: Angle Class II malocclusion. Treatment outcome. Activator appliances.

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