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

Abstract The Evaluation of Soft and Hard Tissue Change for Retraction of Lower Anterior Tooth in Bimaxillary Protrusion Patients acco rding to Two Different Therapeutic Methods: Mandibular Anterior Segme ntal Osteotomy and Orthodontic Treatment with Teeth Extraction Young-Joo Kim, Kyung-A Kim 1 , Yong-Jae Yu, Kyung-Sun Ryu, Jeong-Min Ryu, Joo-Young Ohe, Su-Jung Kim 1 , Seoung-Hun Kim 1 , Baek-Soo Lee Departments of Oral and Maxillofacial Surgery, 1 Orthodontics, Kyung Hee University School of Dentistry Purpose: The purpose of the study is to evaluate the effectiveness of a nterior segmental osteotomy (ASO) in bimaxillary protrusion (BP) patients by comparison between the mandibular s oft and hard tissue changes from orthodontic treatment and ASO.Methods: All 44 patients were diagnosed with BP in Kyung-Hee Medical Ce nter. Orthodontic treatment with teeth extractions were underwent by 23 patients (Group A) and 21 patients underwe nt ASO (Group B). Mandibular soft and hard tissue changes were measured and evaluated, which were based on the vertical a nd horizontal reference line in lateral cephalometric radiograp hs. Statistical significance between the changes and correlation be tween each measurement were analyzed.Results: The amount of B point movement was lesser than that of the low er 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 low er 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 l ower 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. Consequent ly, ASO is more effective in BP cases because it ensures the controlled movement of the lower incisors.Key words:Bimaxillary protrusion, Anterior segmental osteotomy, Ort hodontic treatment