Dong-Yeon Kim1, Ji-Hwan Kim1, Hae-Young Kim2, Woong-Chul Kim3. 1. Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Republic of Korea. 2. Department of Public Health Science, Graduate School&BK21+Program in Public Health Sciences, Korea University, Seoul, Republic of Korea. 3. Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Republic of Korea. Electronic address: kuc2842@korea.ac.kr.
Abstract
PURPOSE: To evaluate the marginal and internal gaps of cobalt-chromium (Co-Cr) alloy copings fabricated using subtractive and additive manufacturing. METHODS: A study model of an abutment tooth 46 was prepared by a 2-step silicone impression with dental stone. Fifteen stereolithography files for Co-Cr alloy copings were compiled using a model scanner and dental CAD software. Using the lost wax (LW), wax block (WB), soft metal block (SMB), microstereolithography (μ-SLA), and selected laser melting (SLM) techniques, 15 Co-Cr alloy copings were fabricated per group. The marginal and internal gaps of these Co-Cr alloy copings were measured using a digital microscope (160×), and the data obtained were analyzed using the non-parametric Kruskal-Wallis H-test and post-hoc Mann-Whitney U-test with Bonferroni correction. RESULTS: The mean values of the marginal, axial wall, and occlusal gaps were 91.8, 83.4, and 163μm in the LW group; 94.2, 77.5, and 122μm in the WB group; 60.0, 79.4, and 90.8μm in the SMB group; 154, 72.4, and 258μm in the μ-SLA group; and 239, 73.6, and 384μm in the SLM group, respectively. The differences in the marginal and occlusal gaps between the 5 groups were statistically significant (P<.05). CONCLUSIONS: The marginal gaps of the LW, WB, and SMB groups were within the clinically acceptable limit, but further improvements in the μ-SLA and SLM approaches may be required prior to clinical implementation.
PURPOSE: To evaluate the marginal and internal gaps of cobalt-chromium (Co-Cr) alloy copings fabricated using subtractive and additive manufacturing. METHODS: A study model of an abutment tooth 46 was prepared by a 2-step silicone impression with dental stone. Fifteen stereolithography files for Co-Cr alloy copings were compiled using a model scanner and dental CAD software. Using the lost wax (LW), wax block (WB), soft metal block (SMB), microstereolithography (μ-SLA), and selected laser melting (SLM) techniques, 15 Co-Cr alloy copings were fabricated per group. The marginal and internal gaps of these Co-Cr alloy copings were measured using a digital microscope (160×), and the data obtained were analyzed using the non-parametric Kruskal-Wallis H-test and post-hoc Mann-Whitney U-test with Bonferroni correction. RESULTS: The mean values of the marginal, axial wall, and occlusal gaps were 91.8, 83.4, and 163μm in the LW group; 94.2, 77.5, and 122μm in the WB group; 60.0, 79.4, and 90.8μm in the SMB group; 154, 72.4, and 258μm in the μ-SLA group; and 239, 73.6, and 384μm in the SLM group, respectively. The differences in the marginal and occlusal gaps between the 5 groups were statistically significant (P<.05). CONCLUSIONS: The marginal gaps of the LW, WB, and SMB groups were within the clinically acceptable limit, but further improvements in the μ-SLA and SLM approaches may be required prior to clinical implementation.
Authors: Wilson Matsumoto; Paula Pastana Beraldo; Rossana Pereira de Almeida; Ana Paula Macedo; Beatriz Roque Kubata; Takami Hirono Hotta Journal: Int J Dent Date: 2018-10-30