Lecturer, Department of Materials Science and Technology, Faculty of Odontology, Malmö University, Malmö, Sweden.
Graduate student, Department of Materials Science and Technology, Faculty of Odontology, Malmö University, Malmö, Sweden.
J Prosthet Dent. 2017 Jul;118(1):95-101. doi: 10.1016/j.prosdent.2016.09.025. Epub 2016 Dec 23.
New production methods have been developed for metal-ceramic restorations. Different production methods may show different surface roughness and fit, which may affect retention and long-term success.
The purpose of this in vitro study was to examine 3 different production methods with regard to surface roughness, marginal and internal fit, and retention of cobalt-chromium alloy single-crown copings.
A master abutment of a premolar mandibular tooth preparation with 4-mm height and a 0.6-mm deep 120-degree chamfer finish line with a 12-degree angle of convergence was replicated in die stone and scanned. Thirty-six cobalt-chromium alloy copings were produced using 3 different production techniques. Twelve copings were produced by laser-sintering, 12 by milling, and 12 by milled wax/lost wax. The surface microstructure of 2 copings in each group was analyzed using interferometry. The remaining 10 copings in each group were used to evaluate marginal and internal fit by using an impression material replica method, and retention was evaluated by using a uniaxial tensile force pull-off test. The copings from each test group were cemented with zinc phosphate cement onto resin abutments. Statistical analyses of differences in marginal and internal fit were performed using 1-way ANOVA and the Mann-Whitney U test. Differences in surface topography were analyzed with the Kruskal-Wallis and Mann-Whitney U tests for nonparametric data. Differences in retentive values were analyzed using the Mann-Whitney U test for nonparametric data (all α=.05).
Differences in surface microstructure were seen. The laser-sintered copings showed increased surface roughness compared with milled and milled wax/lost wax copings. Differences in marginal and internal fit were noted. Laser-sintered showed significantly smaller spaces between coping and abutment than milled wax/lost wax copings (P=.003). At the margins, laser-sintered copings showed significantly smaller spaces than either the milled wax/lost wax group (P=.002) or the milled group (P=.002). At the chamfer, laser-sintered copings showed significantly smaller spaces than milled wax/lost wax copings (P=.005). At the center of the axial walls, laser-sintered copings showed significantly smaller spaces than those in the milled wax/lost wax (P=.004) and milled copings (P=.005). No significant differences were noted between milled and milled wax/lost wax copings (P>.05). No significant differences were detected regarding retentive forces in the pull-off tests (P>.05).
Laser-sintered Co-Cr crown copings showed increased surface roughness and better internal and marginal fit than copings produced by milling or milled wax/lost wax technique. However, the crown pull-off tests did not reveal any significant differences.
金属陶瓷修复体的新生产方法已经开发出来。不同的生产方法可能表现出不同的表面粗糙度和适配性，这可能会影响固位力和长期效果。
本体外研究的目的是检查 3 种不同的生产方法对钴铬合金单冠修复体的表面粗糙度、边缘和内部适配性以及固位力的影响。
通过复制下颌前磨牙牙体预备的石膏模型并进行扫描，制作一个高度为 4mm、深 0.6mm、120°倒角刃线和 12°会聚角的预备体的金属模型。使用 3 种不同的生产技术生产 36 个钴铬合金修复体。其中 12 个通过激光烧结、12 个通过铣削、12 个通过铣削蜡/失蜡法生产。每组中的 2 个修复体的表面微观结构使用干涉测量法进行分析。每组其余 10 个修复体通过印模材料复制法评估边缘和内部适配性，通过单轴拉伸拔出试验评估固位力。将每个测试组的修复体用磷酸锌水门汀粘接到树脂基台上。使用单因素方差分析和曼-惠特尼 U 检验对边缘和内部适配性的差异进行统计学分析。使用 Kruskal-Wallis 和曼-惠特尼 U 检验对非参数数据进行表面形貌差异分析。使用非参数数据的曼-惠特尼 U 检验分析固位力的差异（所有α=0.05）。
观察到表面微观结构的差异。激光烧结修复体的表面粗糙度比铣削和铣削蜡/失蜡修复体高。边缘和内部适配性存在差异。激光烧结修复体与蜡/失蜡组相比，修复体与基台之间的间隙明显更小（P=0.003）。在边缘处，激光烧结修复体与蜡/失蜡组（P=0.002）或铣削组（P=0.002）相比，间隙明显更小。在倒角处，激光烧结修复体与蜡/失蜡修复体相比，间隙明显更小（P=0.005）。在轴向壁的中心处，激光烧结修复体与蜡/失蜡（P=0.004）和铣削蜡/失蜡（P=0.005）修复体相比，间隙明显更小。铣削和蜡/失蜡修复体之间没有明显差异（P＞0.05）。在拔出试验中，没有发现固位力有显著差异（P＞0.05）。
激光烧结钴铬合金冠修复体的表面粗糙度增加，内部和边缘适配性优于铣削或铣削蜡/失蜡技术生产的修复体。然而，冠拔出试验并未显示出任何显著差异。
