Analysis of all ceramic restorations in different CAD/CAM restorations

• Main Authors: Chih-Hao Chang, 張志豪
• Other Authors: Chun-Cheng Hung
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/83316228334431809208

碩士 === 高雄醫學大學 === 牙醫學研究所 === 97 === Objective: Internal and marginal fitness are the most commonly used parameters in measuring dental restorations. The majority of current CAD/CAM systems use indirect method to obtain intra-oral information. Change of occlusal height, marginal and internal fitness were used in this study to evaluate the influences of direct and indirect digital techniques for CAD/CAM restorations.. Materials & methods: Implant analog (048.160, ITI System; Straumann) was used to replace the teeth 25. Three CAD/CAM systems, Cerec 3D, Cerec inLab and Procera systems were used in this study. For Cerec 3D system, intra-oral camera combined with anti-reflecting powder was used to collect abutment information; Cerec inLab and Procera use laser scan and mechanical contact digitalization respectively. VITA MARK II blocks were used for Cerec inLab and Cerec 3D systems while zirconia was used in procera. Each sample was made directly into the form of a single crown,five samples for each group. No post-treatments were made in order to avoid further deformities. All samples were fit back to the standard model to insure no interference present. 3D coordinate measuring machine was used to measure changes of occlusal surface and mark the location of cutting lines. Samples were set with zinc phosphate cement. Continuously static pressure of 50 Newton was applied until cement completely set. Multiple cutting methods were used to observe the internal and marginal fitness. Interactions between multiple factors, including marginal and internal fitness, different CAD/CAM systems, surfaces were incorporated into the statistical module settings (α = 0.05). If the sample size of statistic models cannot reach normal distribution and Central Limit Theorem, nonparametric statistics（Kruskal-Wallis/ Wilcoxon Rank Sum / Signed Rank Test） were used to analyze the data（α＝0.05）. Results: Mean marginal fitness was 114.3 ± 26.83μm, no difference between surfaces. Cerec 3D group was significantly larger while Cerec inLab and Procera did not difference from each other. Mean internal fitness was 123.2 ± 35.93μm, no difference between Cerec 3D and Cerec inLab groups. Internal fitness was significantly different between surfaces, height and CAD/CAM systems. Change in occlusal height had an average of 112.0 ± 110.25μm, Procera and Cerec inLab did not differ from each other and Cerec 3D group was significantly larger. Change in occlusal height was significantly different between occlusal measuring points and CAD/CAM systems. Conclusion: Direct digitalization technique simplified clinical procedures while, less accuracy and precision for direct method comparing with indirect digitalization method was noticed under our experimental limitation