背景:临时牙冠用于在骨整合过程中和之后恢复植入物。然而,关于植入物支持的临时冠的适应性和断裂强度的研究很少。
目的:这项体外研究的目的是评估传统的边缘配合和骨折阻力,减法,以及制造植入物支撑的临时冠的附加方法。
方法:将植入物放置在第一磨牙缺失的环氧树脂模型中。附有扫描体,用口内扫描仪(IOS)扫描,STL文件用于制造18个具有标准化植入物数字模拟空间的主模型。将数字类似物及其相应的基台附加到主模型上,并用IOS进行扫描,STL文件用于使用三种不同的技术(n=6)制造18个牙冠:常规(CR);来自自聚合复合树脂,消减(SM);从PMMA树脂坯料铣削,和添加剂(AM);来自3D打印树脂材料。将牙冠安装并粘合在其相应的基台上,并承受循环载荷和热循环。使用立体显微镜评估边缘拟合。然后在通用试验机中加载牙冠直到断裂。Shapiro-Wilk和Kolmogorov-Smirnov检验表明,边际差距的数据是非参数的。使用Kruskal-Wallis检验和Dunn检验(α=0.05)。而断裂阻力试验的数据是参数化的。使用ANOVA(F检验),随后使用Tukey检验(α=0.05)。
结果:对于边际差距,根据Kruskal-Wallis检验,研究组之间存在显著差异(P=.001).与CR组相比,SM组和AM组的边缘间隙值显着降低(P=0.003)。SM组和AM组之间无显著差异(P=.994)。对于抗断裂性,单因素方差分析显示,研究组间骨折阻力存在显著差异(P<.001)。SM组的断裂强度明显高于AM组和CR组(P=0.001)。
结论:SM组和AM组表现出比CR组更好的边缘适应。与其他组相比,SM组表现出优越的抗骨折性。所有研究组均表现出可接受的边缘间隙和抗断裂性。
BACKGROUND: Interim crowns are utilized for restoring implants during and after the process of osseointegration. However, studies on adaptation and fracture strength of implant-supported interim crowns are rare.
OBJECTIVE: The aim of this in vitro study is evaluating marginal fit and fracture resistance of conventional, subtractive, and additive methods of fabricating implant-supported interim crowns.
METHODS: An implant was placed in an epoxy resin model with a missing first molar. A scan body was attached, and scanned with an intraoral scanner (IOS), the STL file was used to fabricate eighteen master models with standardized implant digital analogue spaces. The digital analogues and their corresponding abutments were attached to the master models and scanned with the IOS, the STL files were used to fabricate eighteen crowns using three different techniques (n = 6): conventional (CR); from Autopolymerizing composite resin, subtractive (SM); milled from PMMA resin blanks, and additive (AM); from 3D printed resin material. The crowns were fitted and cemented on their corresponding abutments and subjected to cyclic loading and thermocycling. The marginal fit was evaluated using a stereomicroscope. The crowns were then loaded until fractured in a universal testing machine. The Shapiro-Wilk and the Kolmogorov-Smirnov tests revealed that data of Marginal gap was non-parametric. Kruskal-Wallis test followed by the Dunn test was used (α = 0.05). While data of Fracture resistance test was parametric. ANOVA (F-test) was used followed by the Tukey test (α = 0.05).
RESULTS: For marginal gap, a significant difference was shown between the study groups (P = .001) according to Kruskal-Wallis test. Groups SM and AM had significantly lower marginal gap values compared to group CR (P = .003). No significant difference was found between groups SM and AM (P = .994). For fracture resistance, One-way ANOVA revealed a significant difference in fracture resistance between study groups (P < .001). Group SM had significantly higher fracture strength followed by group AM and group CR (P = .001).
CONCLUSIONS: Group SM and AM showed better marginal adaptation than group CR. Group SM showed superior fracture resistance compared to other groups. All study groups showed acceptable marginal gap and fracture resistance.