Aim: Milling-based, subtractive fabrication of digital complete dentures represents the computer-engineered manufacturing method of choice. However, efficient additive manufacturing technologies might also prove beneficial for the indication. The aim of the present study was to evaluate the accuracy of surface adaptation of complete denture bases fabricated using subtractive, additive, and conventional manufacturing techniques.
Materials and methods: A standardized edentulous maxillary model was digitally designed and milled. Twelve duplicated plaster casts were scanned and virtual denture bases designed accordingly. Physical complete denture bases (n = 12 per technique) were manufactured applying different digital and conventional fabrication methods: 1) CNC milling (MIL); 2) material jetting (MJ); 3) selective laser sintering (SLS); 4) digital light processing (DLP); and 5) conventional injection molding (INJ). The INJ group served as control. The intaglio surfaces of the denture bases were digitized and superposed with the surface data of the casts using a best-fit algorithm. Accuracy of surface adaptation was assessed by examining deviations. Statistical analysis was conducted using SPSS (P < 0.05).
Results: The milling of denture bases led to significantly better surface adaptation compared with all the other technologies (P < 0.001). The other fabrication methods in the study, including conventional manufacturing, revealed no considerable overall differences.
Conclusions: As regards the accuracy of surface adaptation, all the investigated technologies adequately produced complete denture bases, with milled denture bases presenting the most superior results.
Keywords: 3D printing, additive manufacturing, CAD/CAM, digital complete denture, digital light processing, denture fit, material jetting, milling, PolyJet technology, selective laser sintering