游离端半精密附着体义齿的支持骨表面应力分析

【目的】研究双侧游离缺失活动义齿使用不同类型的半精密附着体时周围支持骨组织的生物力学特征。【方法】采用电阻应变测量法 ,在人体下颌骨标本上测量基牙联冠数目分别为 1,2 ,3单位的冠内及冠外半精密附着体式双侧游离缺失活动 固定联合修复体的表面应力值 ,并做统计分析。【结果】基牙数目从 1个增至 2个 ,支持骨组织应力分布明显变均匀 ,但基牙数目从 2个增至 3个时 ,应力值的改变无显著差异 ;冠内附着体在基牙周围牙槽骨上产生的总体应力较大 ,而冠外附着体在缺牙区牙槽嵴和近缺隙侧基牙远中颈部牙槽嵴上产生的应力较大。【结论】在设计游离端附着体义齿时 ,基牙联冠不宜跨度过大 ;附着体类型的选择应根据缺牙区牙槽嵴及远中基牙牙体、牙周条件酌情而定。

The Surface Stress Analysis of the Supporting Bone Tissue of Distal Extension Denture Retained with Semi precision Attachment

Objectivel To measure the surface stress of the periodontal supporting bone of bilateral distal extension removable partial denture retained by intracoronal or extracoronal attachment and with different number of abutments by strain gauge. Method Strain gauges were bonded in the human mandible to measure the surface stress of bilateral distal extension removable partial denture retained by intracoronal or extracoronal attachments and with different number of abutments. Results Increasing the splinted abutment number from 1 to 2, the stress distribution significantly became more evenly, but increasing the number from 2 to 3, there were no significant changes in stress values. Intracoronal attachment generally produced higher stress in the alveolar bone around the abutments than the extracoronal attachment, but extracoronal attachment produced higher stress in the edentulous alveolar crest and distal cervical alveolar bone of the distal abutment than the intracoronal attachment. Conclusion While designing the attachment retained distal extension removable partial denture, the splinted abutment span should not be too long. The selection of intracoronal or extracoronal attachment should be decided by different situations of the periodontal condition of distal abutment and the edentulous alveolar crest.