Implant-Prosthodontic Discrepancy of Complete-Arch Cobalt-Chromium Implant Frameworks Manufactured Through Selective Laser Melting Additive Manufacturing Technology Using a Coordinate Measuring Machine

Purpose: The objective was to measure the implant-prosthodontic discrepancy of complete-arch implant-supported frameworks made of cobalt-chromium (Co-Cr) fabricated using selective laser melting (SLM) additive manufacturing technologies. Materials and Methods: A completely edentulous maxillary cast with seven implant replicas was obtained. Co-Cr SLM frameworks (n = 9) from three different providers (SLM-1, SLM-2, SLM-3) were manufactured. A coordinate measuring machine was selected to measure the implant-prosthodontic discrepancy (μm) on the x-, y-, and z-axes and the 3D gap (3D = √x2 + y2 + z2 where implants were considered as the statistical unit (n = 7). One-way analysis of variance (ANOVA), Student-Newman- Keuls, and Tukey tests were used to analyze the data (α = .05). Results: The mean 3D implant-prosthodontic discrepancy (μm) was higher for SLM-1 (73.77 ± 27.94) than for SLM-2 (47.54 ± 22.63) and SLM- 3 (47.26 ± 22.57). At the x-axis, SLM-2 showed a significantly smaller gap (16.21 ± 9.6) than SLM-3 (32.92 ± 27.77) and SLM-1 (34.77 ± 21.85). At the y-axis, however, SLM-3 presented a significantly smaller gap (27.97 ± 9.49) than SLM-2 (38.84 ± 27.82) and SLM-1 (54.35 ± 29.89). Similarly, at the z-axis, SLM-3 (4.01 ± 2.29) showed the least gap, followed by SLM-2 (9.09 ± 7.63), which was significantly smaller than that of SLM-1 (16.14 ± 21.09). Conclusion: The three SLM additive manufacturing technologies tested showed implant-prosthodontic discrepancies ranging from 4.01 to 54.35 μm, which could be considered in the clinically acceptable range. Distortion at the z-axis was significantly less compared with the x- and y-axes in all the groups tested. Keywords: 3D printing, additive manufacturing technologies, chrome-cobalt, implant-prosthodontic gap, selective laser melting