Marginal Fit of Temporary Restorations Fabricated by the Conventional Chairside Method, 3D Printing, and Milling.

This study aimed to compare the marginal fit of temporary restorations fabricated by the conventional chairside method, 3D printing, and milling. In this in vitro, experimental study, 14 temporary restorations were conventionally fabricated over an implant abutment and analog that had been mounted in a phantom model at the site of canine tooth, using auto-polymerizing acrylic resin and putty index. In digital manufacturing, the original model was scanned, and the final restoration was designed. Fourteen temporary restorations were milled out of polymethyl methacrylate (PMMA) blocks, and 14 others were printed by a 3D printer. Temporary crowns were placed on the abutment, and images were obtained from specific areas under a stereomicroscope at x100 magnification to measure the amount of marginal gap. Data were analyzed using one-way ANOVA and Tukey's test (α=0.05). The mean marginal gap values for the temporary crowns in the 3D printing, milling, and chairside groups were 91.40, 75.28 and 51.23 µm, respectively. The crowns that were conventionally fabricated chairside exhibited the lowest marginal gap, and the difference in this respect was significant among the three groups (P<0.05). Temporary crowns fabricated by the chairside method showed significantly smaller marginal gap; however, the marginal gap of all three groups was within the clinically acceptable range.