Effects of fabrication techniques on denture base adaptation: An in vitro study.

STATEMENT OF PROBLEM: Information about the accuracy of maxillary and mandibular denture bases made with different fabrication techniques under uniform test conditions is lacking. PURPOSE: The purpose of this in vitro study was to evaluate the denture base adaptation of computer-aided design and computer-aided manufactured (CAD-CAM) milled, 3D printed, and conventional heat-polymerized resin fabrication techniques. MATERIAL AND METHODS: Maxillary and mandibular edentulous models fabricated from cobalt-chromium alloy were scanned, and 2-mm-thick denture bases were designed and fabricated by using 4 fabrication techniques and materials: CAD-CAM milled (CCM), 3D printed (3DP), injection molded (IM), and compression molded (CM). Denture base adaptation was assessed by measuring the thickness of silicone between the denture base and model under a 49-N load at 8 sites. A digital superimposition method was used to compare different groups, and adaptation was assessed by superimposing the scanning data from denture bases and models. The pairwise Wilcoxon signed rank test and Kruskal-Wallis analysis of variance were used for statistical analyses (alpha=.05). RESULTS: According to the silicone thickness method, the lowest values (0.127-0.567 mm) were present at the bilateral maxillary tuberosities, and the highest values (0.529-2.211 mm) occurred at the postpalatal seal area in all groups. The CCM group had the lowest silicone thickness (P<.05). The 3DP group recorded greater thickness than the IM and CM groups (P<.05). In the mandible, the 3DP group recorded the lowest silicone thickness, followed by the CCM group. The overall results for digital superimposition revealed no significant difference (P>.05) in the trueness of the intaglio surfaces among CCM, IM, and CM. The 3DP group recorded the lowest trueness significantly among all the groups. CONCLUSIONS: CCM, IM, and CM exhibited superior denture adaptation, especially CCM, to both maxillary and mandibular arches compared with 3DP.