固定桥基牙牙槽骨三侧吸收对基牙应力分布的影响

Effects of Three-side Absorption of Alveolar Bone in Rigid Fixed Bridge on the Stress Distribution of Abutments

目的:研究双端固定桥基牙牙槽骨三侧吸收对基牙应力分布的影响。方法:采用螺旋CT扫描获取健康人下颌骨、牙齿及牙周支持组织的二维图像,通过图像合成软件建立三维数字模型,并应用三维有限元分析软件生成下颌后牙三单位固定桥的三维有限元分析模型。在相同垂直和水平载荷情况下,分析基牙牙槽骨三侧吸收时固定桥各基牙的应力分布。结果:当前磨牙端基牙牙槽骨三侧吸收达15%、磨牙端基牙牙槽骨无吸收时,前磨牙端基牙开始出现应力集中;当磨牙端基牙牙槽骨三侧吸收达25%、前磨牙端基牙牙槽骨无吸收时,磨牙端基牙开始出现应力集中。结论:下颌后牙固定桥基牙牙槽骨吸收形式的不同直接影响着其应力分布,基牙牙槽骨三侧吸收的程度对基牙应力分布的影响强于单侧和多侧吸收时。

Objective：To study the effects of three-side absorption of alveolar bone on the stress distribution around the abut-ment teeth of rigid fixed bridges.Methods：Two-dimensional images of mandibular bone,teeth and periodontal supporting tissue of healthy people were obtained by spiral CT.Three-dimensional digital model was developed by imaging software.Then the three-dimensional finite element model of three-unit fixed bridge of mandibular posterior teeth was developed.With asorption of three-side alvoelar bone,stress distribution around the abutment teeth of fixed bridge was analyzed under the ver-tical and horizontal load.Results：When three-side alveolar bone absorption around the premolar abutment reached 15% and no absorption in the alveolar bone around the molar abutment,stress concentration appeared in the premolar area.When three-side absorption of alveolar bones around the molar abutment reached 25% and no absorption in the alveolar bones around the premolar abutment,stress concentration appeared in the molar area.Conclusions：Differences in the alveolar bone absorption of abutment teeth of the posterior fixed bridge directly affected the stress distribution around the abutment.Influence of three-side absorption of the alveolar bone on the abutment stress distribution was more severe than those of one-side and two-side alveolar bone absorption.