下颌固定桥基牙牙槽骨单侧吸收对基牙应力分布的影响

目的:研究双端固定桥基牙牙槽骨单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、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,分析基牙牙槽骨单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单侧吸收达25%、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单侧吸收达35%、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:下颌后牙双端固定桥基牙应力分布与基牙牙槽骨吸收形式密切相关,但二者之间不是线性关系而是存在临界区,基牙牙槽骨单侧吸收的程度对基牙应力分布的影响弱于多侧吸收。

Influences of single-side absorption of alveolar bone in rigid fixed bridge on the stress distribution of abutments

AIM:To study the effects of single-side absorption of alveolar bone in rigid fixed bridge on the stress distribution of abutments.METHODS:Two-dimensional images of mandibular bone,teeth and periodontal supporting tissue of healthy people were scanned by spiral CT.Three-dimensional digital model were developed by imaging software.Then the three-dimensional finite element model of fixed denture on mandibular posterior teeth was developed.Stress distribution of fixed bridge loaded with the same vertical and horizontal forces was analyzed during single-side absorption of alveolar bone around abutments.RESULTS:When single-side absorption of alveolar bone around a premolar abutment reached 25% and no absorption of alveolar bone around a molar abutment,the stress of premolar abutment would be concentrated.When single-side absorption of alveolar bones around a molar abutment reached 35% and no absorption of alveolar bones around a premolar abutment,the stress of molar abutment would be concentrated.CONCLUSION:There was a non-linear relationship between stress concentration of abutments of fixed denture on mandibular posterior teeth and absorption of alveolar bone around abutments.The effects of single-side absorption of alveolar bones on the stress distribution of abutments were less than multi-side absorption of alveolar bones.