Comparison and evaluation of marginal and internal gaps in cobalt-chromium alloy copings fabricated using subtractive and additive manufacturing.

Author(s) Kim, D.Y.; Kim, J.H.; Kim, H.Y.; Kim, W.C.
Journal J Prosthodont Res
Date Published 2017 Jun 26
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.

DOI 10.1016/j.jpor.2017.05.008
ISSN 2212-4632
Citation Kim D-, Kim J-, Kim H-, Kim W-. Comparison and evaluation of marginal and internal gaps in cobalt-chromium alloy copings fabricated using subtractive and additive manufacturing. J Prosthodont Res. 2017.

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