【摘要】 目的比较不同的扫描对象对计算机辅助设计(CAD)/计算机辅助制造(CAM)钴铬烤瓷冠精确性的影响。方法利用CAD/CAM技术制作15个钴铬烤瓷冠试件,根据不同的扫描对象:预备离体牙、硅橡胶印模和石膏模型,均分为实验B组(B1、B2和B3组),另外使用传统失蜡法铸造5个试件作为对照(A组),采用微计算机断层扫描技术比较边缘(AMD点和MG点)及内部适合性(CA点、AW点、AOT点、OA点)的差异,对结果进行单因素方差分析和配对t检验。结果在边缘适合性上,B组AMD点的数值均明显小于A组(P<0.05),两组在MG点上的差异无统计学意义;在内部适合性上,B组除OA点外的其他位点的测量数值均小于A组,其中AOT、AW、OA点B1、2组与A组的测量差异有统计学意义(P<0.05),B3组与A组的差异无统计学意义(P>0.05);B组与A组CA点的差异均无统计学意义(P>0.05)。结论硅橡胶印模的精确性明显优于预备后的离体牙及石膏模型,CAD/CAM相比传统失蜡铸造技术来说,试件具有更佳的边缘及内部适合性。更多还原

【Abstract】 Objective To evaluate the effects of different scanning objects on the accuracy of computer aided design(CAD)/computer aided manufacture(CAM) Co-Cr metal porcelain crowns. Methods Fifteen Co-Cr metal porcelain crown specimens were fabricated by CAD/CAM technology. According to different scanning objects: prepared teeth, silicone rubber and stone die, they were divided into experimental B groups(group B1, B2, B3). Five specimens of traditional lost wax casting were used as control(group A). Marginal fits(AMD point and MG point) and internal fits(CA point, AW point, AOT point and OA point) were measured by the micro-CT. Statistical analysis was performed via one-way ANOVA and paired-t-test. Results The AMD point’ marginal fits of the experimental B groups were smaller than group A(P<0.05), there was no statistic difference in MG point’ marginal fits between the experimental B groups and group A. The experimental B groups had smaller internal fits than group A except OA point. The internal fits of group B1, 2 were smaller than the group A at AOT, AW and OA points(P<0.05), except group B3(P>0.05). There was no statistic difference in CA point’ internal fits between the experimental B groups and group A(P>0.05). Conclusion The accuracy of silicone rubber is higher than the prepared tooth and stone die. Comparing to the traditional casting, the CAD/CAM has better marginal and internal fits.更多还原