Precision of the milled full-arch framework fabricated using pre-sintered soft alloy: A pilot study

PURPOSE: This study aimed to evaluate the marginal discrepancy of full-arch frameworks in implant-supported prostheses fabricated using pre-sintered soft alloy (PSA). MATERIALS AND METHODS: Full-arch metal frameworks were fabricated on the edentulous implant model using casting alloy (CA), fully-sintered hard alloy (FHA), and PSA (n = 4 in each group). To evaluate the misfit of the framework to the abutments, the absolute marginal discrepancy (AMD) values of the frameworks were measured in cross-sectional images that had been drawn as part of the triple-scan protocol. The AMD values were compared among the tested alloy groups using the Kruskal-Wallis test, with a post hoc Mann-Whitney U test (α=.05). RESULTS: The FHA and PSA groups showed lower marginal discrepancies than the CA group (P<.001). However, the FHA group did not differ significantly from the PSA group. CONCLUSION: Soft alloy milling is comparable to hard alloy milling, and it is more precise than casting in terms of the marginal fit of implant-supported, full-arch prostheses.