Gholamrezaei Koosha, Vafaee Fariborz, Afkari Behzad Fathi, Firouz Farnaz, Seif Mozhgan
School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Department of Prosthodontics, School of Dental Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
Dent Res J (Isfahan). 2020 May 23;17(3):200-207. eCollection 2020 May-Jun.
This study aimed to assess the marginal adaptation and internal fit of cobalt-chromium copings fabricated by the selective laser melting (SLM) and conventional techniques using a profilometer.
In this study sample size was calculated to be a total of 10 in two groups ( = 5). A brass model was used that had a circular cross-section with a round shoulder margin with 0.5 mm thickness and axial walls with 10 mm length and 6° taper. The copings fabricated with both techniques (SLM and casting method) were placed on the model, and vertical marginal gap was measured using a profilometer. The internal fit of copings was assessed by weighing the light-body addition silicone applied inside them, which simulated the cement. Data were analyzed through parametric (Independent t-test) and nonparametric (Mann-Whitney U-test, Bootstrap, Spearman, and Pearson Correlation) analysis. All analyses were performed at a significant level (α = 0.05) using SPSS.
The mean marginal gap in the casting group (132.93 ± ) was significantly higher than that in the SLM group (67.14 ± 15.67 μm) ( < 0.05). The mean weight of light-body silicone was 9.60 ± in the SLM and 8.70 ± 1.21 mg in the casting group. No significant difference was noted between the two groups regarding the internal fit ( > 0.05).
The copings fabricated by the SLM technique showed a smaller vertical marginal gap compared to the casting group. However, the two groups were not significantly different in terms of internal fit.
本研究旨在使用轮廓仪评估通过选择性激光熔化（SLM）和传统技术制造的钴铬修复体的边缘适合性和内部适合性。
在本研究中，计算得出两组的样本量总计为10个（每组 = 5个）。使用了一个黄铜模型，其具有圆形横截面，带有0.5毫米厚的圆形肩台边缘以及长度为10毫米且锥度为6°的轴向壁。将两种技术（SLM和铸造法）制造的修复体放置在模型上，并使用轮廓仪测量垂直边缘间隙。通过称量施加在修复体内模拟粘固剂的轻质添加型硅橡胶来评估修复体的内部适合性。通过参数分析（独立t检验）和非参数分析（曼-惠特尼U检验、自助法、斯皮尔曼和皮尔逊相关性分析）对数据进行分析。所有分析均使用SPSS在显著水平（α = 0.05）下进行。
铸造组的平均边缘间隙（132.93 ± ）显著高于SLM组（67.14 ± 15.67μm）（ < 0.05）。SLM组轻质硅橡胶的平均重量为9.60 ± ，铸造组为8.70 ± 1.21毫克。两组在内部适合性方面未观察到显著差异（ > 0.05）。
与铸造组相比，SLM技术制造的修复体显示出较小的垂直边缘间隙。然而，两组在内部适合性方面没有显著差异。
