Alikhasi Marzieh, Ameri Narges, Siadat Hakimeh, Shamshiri Ahmad Reza, Nejati Mohammadreza
Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Front Dent. 2019 May-Jun;16(3):194-205. doi: 10.18502/fid.v16i3.1591. Epub 2019 Jun 29.
Internal fit of implant frameworks is an important factor determining the long-term success of dental implant restorations. This in-vitro study aimed to evaluate dimensional changes of implant-supported zirconia frameworks fabricated by two computer-aided design/computer-aided manufacturing (CAD/CAM) systems from scanning to sintering.
A master model of a three-unit fixed partial denture was fabricated with two implant abutments. In each CAD/CAM system (AmannGirrbach and Zirkonzahn), the master model was scanned 12 times, and data were saved as Standard Transformation Language files (scanning groups). Using semi-sintered zirconia, 12 real-size frameworks (milling groups) and 12 enlarged frameworks, were sintered (sintering groups) and made by each system. Dimensions of the master model and frameworks in each phase were measured. Dimensional changes (compared to the master model) were calculated. Data were analyzed using repeated measures analysis of variance, independent t-test, and paired sample t-test (α=0.05).
Comparison of the two systems revealed that although dimensional changes were greater in the milling phase of Zirkonzahn, they were larger in the sintering phase of the AmannGirrbach system. Evaluation of fabrication phases revealed greater dimensional changes in the milling phase compared to the other phases in the Zirkonzahn system (P<0.05). However, in the AmannGirrbach system, the values were not significantly different between milling and sintering phases (P>0.05).
Within the limitations of this study, the results showed that fabrication phases, CAD/CAM system type and abutment size had significant effects on dimensional changes.
种植体支架的内部适合性是决定牙种植修复长期成功的重要因素。本体外研究旨在评估由两种计算机辅助设计/计算机辅助制造（CAD/CAM）系统制作的种植体支持的氧化锆支架从扫描到烧结过程中的尺寸变化。
制作一个带有两个种植体基台的三单位固定局部义齿的母模。在每个CAD/CAM系统（阿曼吉尔巴赫和齐康赞）中，母模被扫描12次，数据保存为标准转换语言文件（扫描组）。使用半烧结氧化锆，每个系统制作12个实际尺寸的支架（铣削组）和12个放大的支架，并进行烧结（烧结组）。测量每个阶段母模和支架的尺寸。计算尺寸变化（与母模相比）。使用重复测量方差分析、独立样本t检验和配对样本t检验对数据进行分析（α = 0.05）。
两个系统的比较显示，尽管齐康赞系统在铣削阶段的尺寸变化更大，但阿曼吉尔巴赫系统在烧结阶段的尺寸变化更大。对制作阶段的评估显示，与齐康赞系统的其他阶段相比，铣削阶段的尺寸变化更大（P < 0.05）。然而，在阿曼吉尔巴赫系统中，铣削阶段和烧结阶段的值没有显著差异（P > 0.05）。
在本研究的局限性内，结果表明制作阶段、CAD/CAM系统类型和基台尺寸对尺寸变化有显著影响。
