Li Zeng1, Yong Zhang2, Zheng Liu2, Bin Wei3. 1. Intern Doctor, Department of Prosthodontics, Stomatology Special Consultation Clinic, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China. 2. Technician, Department of Technical, Shanghai Foshion Medical System Co Ltd, Shanghai, China. 3. Professor, Department of Prosthodontics, Stomatology Special Consultation Clinic, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China. Electronic address: weibin0328@hotmail.com.
Abstract
STATEMENT OF PROBLEM: Selective laser melting (SLM) is a technique used to fabricate Co-Cr dental restorations; however, because marginal accuracy is important for the long-term success of restorations, the marginal accuracy of SLM after repeated firings must be considered. PURPOSE: The purpose of this study was to evaluate the marginal accuracy of dental Co-Cr alloy copings fabricated by SLM and to investigate the effects of repeated firing on the marginal fit of these copings. MATERIAL AND METHODS: SLM-fabricated and cast Co-Cr alloy copings (n=15) were prepared for a zirconia die. The marginal gap widths of each group were evaluated with a silicone replica technique after the first, third, fifth, and seventh firing cycle. The thickness of the reference point was measured with a stereomicroscope with ×100 magnification. Analysis of variance was used to evaluate the effect of repeated firing on the marginal accuracy of the 2 alloys. The Student t test was used to compare the marginal gap widths of the SLM-fabricated and cast Co-Cr alloy copings after repeated firing (α=.05). RESULTS: The marginal gap width values between the 2 groups at all firing periods were statistically significant (P<.05). The mean marginal gap width values for SLM-fabricated copings were 36 μm, 37 μm, 38 μm, and 38 μm after the first, third, fifth, and seventh firing, while the mean marginal gap width values for cast copings were 67 μm, 71 μm, 72 μm, and 73 μm at the same number of firings. The marginal gap width values within the 2 groups were not statistically different from each other with additional firing (P>.05). CONCLUSIONS: The SLM copings demonstrated superior marginal accuracy at all firings. Repeated firing had no significant influence on the marginal accuracy of both copings, and the marginal fit of both copings after repeated firing was within a clinically acceptable range.
STATEMENT OF PROBLEM: Selective laser melting (SLM) is a technique used to fabricate Co-Cr dental restorations; however, because marginal accuracy is important for the long-term success of restorations, the marginal accuracy of SLM after repeated firings must be considered. PURPOSE: The purpose of this study was to evaluate the marginal accuracy of dental Co-Cr alloy copings fabricated by SLM and to investigate the effects of repeated firing on the marginal fit of these copings. MATERIAL AND METHODS: SLM-fabricated and cast Co-Cr alloy copings (n=15) were prepared for a zirconia die. The marginal gap widths of each group were evaluated with a silicone replica technique after the first, third, fifth, and seventh firing cycle. The thickness of the reference point was measured with a stereomicroscope with ×100 magnification. Analysis of variance was used to evaluate the effect of repeated firing on the marginal accuracy of the 2 alloys. The Student t test was used to compare the marginal gap widths of the SLM-fabricated and cast Co-Cr alloy copings after repeated firing (α=.05). RESULTS: The marginal gap width values between the 2 groups at all firing periods were statistically significant (P<.05). The mean marginal gap width values for SLM-fabricated copings were 36 μm, 37 μm, 38 μm, and 38 μm after the first, third, fifth, and seventh firing, while the mean marginal gap width values for cast copings were 67 μm, 71 μm, 72 μm, and 73 μm at the same number of firings. The marginal gap width values within the 2 groups were not statistically different from each other with additional firing (P>.05). CONCLUSIONS: The SLM copings demonstrated superior marginal accuracy at all firings. Repeated firing had no significant influence on the marginal accuracy of both copings, and the marginal fit of both copings after repeated firing was within a clinically acceptable range.
Authors: Óscar Barro; Felipe Arias-González; Fernando Lusquiños; Rafael Comesaña; Jesús Del Val; Antonio Riveiro; Aida Badaoui; Félix Gómez-Baño; Juan Pou Journal: Materials (Basel) Date: 2022-06-30 Impact factor: 3.748