DIỄN TIẾN HÌNH THÁI KHỚP CẮN TỪ BỘ RĂNG SỮA ĐẾN HỖN HỢP VÀ VĨNH VIỄN Ở NHÓM CÓ TƯƠNG QUAN MẶT PHẲNG TẬN CÙNG RĂNG CỐI SỮA THỨ HAI DẠNG THẲNG

Abstract

Background: There are three types of the final step in the deciduous dentition: flush terminal plane, mesial step and distal step. Although the flush terminal plane typically accounts for the highest proportion and is considered to be one of the factors of "ideal occlusion" of the deciduous dentition, it is about 20-50% to become abnormal Class II molar relationship in the permanent dentition. Therefore, many authors believe that it is necessary to reconsider the notion that the flush terminal plane relationship is one of the criteria for an ideal occlusion in the deciduous dentition. In Vietnam, no studies have been done to evaluate the progression of occlusal morphology of the flush terminal plane during the whole process of the dentition. Thus, we conducted a study "Progress of occlusal morphology from the deciduous to mixed and permanent dentition in flush terminal plane relationship group". It is truly valuable in both research and orthodontic treatment. From the findings, appropriate prevention and intervention plans can be made to help children achieve normal occlusal in the future. Objectives: To evaluate the progression of occlusal morphology of the flush terminal plane group during the whole process of dentition from the deciduous to mixed and permanent dentition. Materials and methods: Longitudinal study on 48 flush relationships of the deciduous dentition. To evaluate the changes of that group from deciduous to mixed and permanent dentition. Results: In 48 flush relationships, when transitioning from the deciduous to the mixed dentition, the conversion rate was 15% and 85% respectively compared with Class I and Class II 50% molar relationship. When change from the mixed dentition to the permanent stage, 100% of the Class I molar relationship will maintain this correlation. For the Class II 50% molar group in the mixed dentition, when switching to the permanent stage, 63% will be converted into Class I molar, and the rest will keep a Class II 50% molar correlation. When changing from the deciduous dentition to the permanent stage, there are 69% will be converted into normal Class I molar, the rest will be converted into Class II molar relationship. Conclusion: During the development from deciduous teeth to permanent teeth, though the flush plane correlation is considered ideal in the deciduous dentition, the transition rate to Class II in the permanent dentition exceeds 30%.