The effect of pattern fabrication methods on the marginal fit of three‐unit implant‐supported frameworks: An experimental study

Abstract Objective This in vitro study aimed to evaluate and compare the marginal fit of three‐unit implant‐supported frameworks fabricated based on conventionally hand‐waxed, milled, and three‐dimensional (3D) printed patterns. Materials and Methods Two fixture analogs were placed in the mandibular right first premolar and first molar region of the dentiform and two prefabricated abutments were secured in the fixture analogs. Thirty three‐unit wax patterns were fabricated through conventional, milling, and 3D printing techniques ( n = 10 per group). After casting, the vertical marginal gaps of two abutments for each restoration were measured by using an optical microscope on 16 points around the finish line at ×80 magnification. The data were analysed by using one‐way ANOVA and Tukey's post hoc test ( α = 0.05). Results The marginal gap was found to be significantly different among the three manufacturing methods ( p < 0.001) and between each pair ( p < 0.001). The 3D printing group had a significantly lower marginal gap than the milling ( p < 0.001) and the conventional group ( p < 0.001) in the first premolar and first molar regions and the mean of the two. The marginal gap in the milling group was significantly lower than that of the conventional group ( p < 0.001) in the first premolar and first molar regions and the mean of the two. Conclusion The marginal fit of the frameworks was the best in the 3D printing method, followed by the milling, and finally the conventional method. However, the fit accuracy in all three methods remained within the clinically acceptable range (<120 μm).