MC CAD/CAM全瓷冠三维有限元应力分析

目的运用三维有限元法分析CAD/CAM全瓷冠受载的应力分布规律,为指导CAD/CAM全瓷冠的临床应用提供理论依据。方法建立下颌第一磨牙MC陶瓷全瓷冠三维有限元模型,全瓷冠设计为单层结构和底层-饰瓷复层结构两种形式,垂直面加载600N,分析不同模型的应力分布。结果全瓷冠在受载时的应力分布形式基本相同,最大应力都在修复体加载点周围,位于面加载点下方,从加载点向周围逐步递减,牙本质内应力较低,分布较均匀,全冠内应力相对较高;两种形式的全瓷冠应力分布无明显差别。结论单层和底层-饰瓷复层两种形式对MC全瓷冠应力分布无明显影响,全瓷冠的面接触点和边缘的强度对其长期应用的完整性影响较大。

3-D finite element analysis of MC CAD/CAM all-ceramic crown

Objective To guide the clinical application for CAD/CAM all-ceramic crown, 3-D finite element analysis was used in this study to evaluate the stress distribution on CAD/CAM all-ceramic crown under load. Methods A three- dimensional finite element model representing a mandibular first molar with MC CAD/CAM all-ceramic crown was constructed. The all-ceramic crown was given two types of design: single-layer porcelain and two-layer porcelain (coping and veneering porcelain). A load of 600N was applied vertically on the crown. Results Stress distribution patterns were basically the same among the two types of all-ceramic crown, with the highest stress located in the crown and just under the occlusal loading point. The stress decreased gradually from the loading point to the circumferential area. The stress in dentin was relatively lower and more evenly distributed than that in the all-cramic crown where bore relatively higher stress. Conclusions No significantly influence was found on the stress distribution in the all-ceramic crown by both types of design with single-layer porcelain and the two-layer porcelain . The strengths of the occlusal loading points and the margins could possibly influence the long-term integrity of MC CAD/CAM all-cermic crowns.