The Evaluation of Soft and Hard Tissue Change for Retraction of Lower Anterior Tooth in Bimaxillary Protrusion Patients according to Two Different Therapeutic Methods: Mandibular Anterior Segmental Osteotomy and Orthodontic Treatment with Teeth Extraction

Kim, Young Joo; Kim, Kyung A; Yu, Yong Jae; Ryu, Kyung Sun; Ryu, Jeong Min; Ohe, Joo Young; Kim, Su Jung; Kim, Seoung Hun; Lee, Baek Soo

Abstract

PURPOSE
The purpose of the study is to evaluate the effectiveness of anterior segmental osteotomy (ASO) in bimaxillary protrusion (BP) patients by comparison between the mandibular soft and hard tissue changes from orthodontic treatment and ASO.
METHODS
All 44 patients were diagnosed with BP in Kyung-Hee Medical Center. Orthodontic treatment with teeth extractions were underwent by 23 patients (Group A) and 21 patients underwent ASO (Group B). Mandibular soft and hard tissue changes were measured and evaluated, which were based on the vertical and horizontal reference line in lateral cephalometric radiographs. Statistical significance between the changes and correlation between each measurement were analyzed.
RESULTS
The amount of B point movement was lesser than that of the lower incisal tip (LIT) retraction, and LIT was tilted lingually in group A. The posterior movement discrepancy between LIT and B point was insignificant, and the inclination of lower incisor was not changed in group B. The soft tissues, including the lower lip, showed a posterior movement and reduction in the depth of mento-labial groove. According to the correlation analysis, the movement of the lower incisor was significantly related to the movement of the lower lip in group A, and the movement of the lower incisor was significantly related to that of the movement of lower lip, B point and Pog in group B.
CONCLUSION
The orthodontic treatment in BP patients results in posterior tilting movement of the lower incisor, but ASO results in the bodily movement of the lower incisor. Consequently, ASO is more effective in BP cases because it ensures the controlled movement of the lower incisors.