Wang Hongmei, Feng Qing, Li Ning, Xu Sheng
Graduate student, Department of Prosthodontics, College of Stomatology, Guangxi Medical University, Nanning, China.
Associate Professor, Department of Prosthodontics, College of Stomatology, Guangxi Medical University, Nanning, China.
J Prosthet Dent. 2016 Dec;116(6):916-923. doi: 10.1016/j.prosdent.2016.06.002. Epub 2016 Jul 25.
Limited information is available regarding the metal-ceramic bond strength of dental Co-Cr alloys fabricated by casting (CAST), computer numerical control (CNC) milling, and selective laser melting (SLM).
The purpose of this in vitro study was to evaluate the metal-ceramic bond characteristics of 3 dental Co-Cr alloys fabricated by casting, computer numerical control milling, and selective laser melting techniques using the 3-point bend test (International Organization for Standardization [ISO] standard 9693).
Forty-five specimens (25×3×0.5 mm) made of dental Co-Cr alloys were prepared by CAST, CNC milling, and SLM techniques. The morphology of the oxidation surface of metal specimens was evaluated by scanning electron microscopy (SEM). After porcelain application, the interfacial characterization was evaluated by SEM equipped with energy-dispersive spectrometry (EDS) analysis, and the metal-ceramic bond strength was assessed with the 3-point bend test. Failure type and elemental composition on the debonding interface were assessed by SEM/EDS. The bond strength was statistically analyzed by 1-way ANOVA and Tukey honest significant difference test (α=.05).
The oxidation surfaces of the CAST, CNC, and SLM groups were different. They were porous in the CAST group but compact and irregular in the CNC and SLM groups. The metal-ceramic interfaces of the SLM and CNC groups showed excellent combination compared with those of the CAST group. The bond strength was 37.7 ±6.5 MPa for CAST, 43.3 ±9.2 MPa for CNC, and 46.8 ±5.1 MPa for the SLM group. Statistically significant differences were found among the 3 groups tested (P=.028). The debonding surfaces of all specimens exhibited cohesive failure mode.
The oxidation surface morphologies and thicknesses of dental Co-Cr alloys are dependent on the different fabrication techniques used. The bond strength of all 3 groups exceed the minimum acceptable value of 25 MPa recommended by ISO 9693; hence, dental Co-Cr alloy fabricated with the SLM techniques could be a promising alternative for metal ceramic restorations.
关于通过铸造（CAST）、计算机数控（CNC）铣削和选择性激光熔化（SLM）制造的牙科钴铬合金的金属-陶瓷结合强度，现有信息有限。
本体外研究的目的是使用三点弯曲试验（国际标准化组织[ISO]标准9693）评估通过铸造、计算机数控铣削和选择性激光熔化技术制造的三种牙科钴铬合金的金属-陶瓷结合特性。
采用铸造、计算机数控铣削和选择性激光熔化技术制备了45个由牙科钴铬合金制成的试样（25×3×0.5mm）。通过扫描电子显微镜（SEM）评估金属试样氧化表面的形态。涂瓷后，通过配备能量色散光谱（EDS）分析的SEM评估界面特征，并通过三点弯曲试验评估金属-陶瓷结合强度。通过SEM/EDS评估脱粘界面上的失效类型和元素组成。通过单因素方差分析和Tukey诚实显著性差异检验（α=0.05）对结合强度进行统计学分析。
铸造组、计算机数控组和选择性激光熔化组的氧化表面不同。铸造组表面多孔，而计算机数控组和选择性激光熔化组表面致密且不规则。与铸造组相比，选择性激光熔化组和计算机数控组的金属-陶瓷界面显示出优异的结合。铸造组的结合强度为37.7±6.5MPa，计算机数控组为43.3±9.2MPa，选择性激光熔化组为46.8±5.1MPa。在测试的三组之间发现了统计学上的显著差异（P=0.028）。所有试样的脱粘表面均呈现内聚破坏模式。
牙科钴铬合金的氧化表面形态和厚度取决于所使用的不同制造技术。所有三组的结合强度均超过ISO 9693推荐的最低可接受值25MPa；因此，采用选择性激光熔化技术制造的牙科钴铬合金可能是金属陶瓷修复体的一种有前景的替代材料。
