This study compared the dimensional changes between computer-aided design and computer-aided manufacturing (CAD-CAM) milled complete denture bases (CDBs) and three-dimensional (3D) printed CDBs. Materials and methods: One maxillary completely edentulous stone model was fabricated with three reference points at the incisive papilla, right molar, and left molar areas marked as X, Y, and Z, respectively. It was scanned to produce a standard tessellation language (STL) file, which was imported to a metal milling machine software to produce the metal model. This metal model was used to fabricate 30 CDBs for analysis. The CDBs were divided into three groups (n = 10 each) according to the fabrication method used as follows: Group 1, CAD-CAM milled CDBs; Group 2, 3D printed CDBs; and Group 3, conventional compression molded CDBs. The CDBs of all groups were scanned after fabrication, and the dimensional changes in each were evaluated by two methods. The first was the two-dimensional evaluation method that involved linear measurement of the distances between the reference points (X-Y, X-Z, and Y-Z) of the scanned reference cast and dentures. The second method was the 3D evaluation method that involved the superimposition of the STL files of the dentures on the STL file of the reference cast. Data were calculated and were statistically analyzed using one-way analysis of variance and Tukey's pairwise post hoc tests. Results: There was a significant difference in the dimensional accuracy between the CAD-CAM milled, 3D printed, and conventional compression molded CDBs (p < 0.05). Conclusion:The dimensional accuracy of the CAD-CAM milling system in complete denture fabrication is superior to that of the compression molding and 3D printing systems.

Purpose To compare the flexural strength of computer‐aided design and computer‐aided manufacturing (CAD‐CAM) milled denture base resin (DBR), 3D‐printed DBR, polyamide, and conventional compression‐molded DBR. Materials and Methods Six denture base resins were used, one conventional heat‐polymerized (Vertex), two milled CAD‐CAM (AvaDent and Polident), two 3D‐printed (Harz and NextDent), and one flexible polyamide (Polyamide). According to ISO 20795‐1:2013, 60 specimens (65×10×3 mm) were constructed and divided into six groups (n = 10), according to DBR type. The flexural strength was measured using a universal testing machine and three‐point loading test. Data were collected and analyzed using one‐way ANOVA and Tukey's pair‐wise post hoc tests (α = 0.05). Results One‐way ANOVA results showed significant differences in flexural strengths between the tested DBRs (p˂0.001). Milled denture base resins (AvaDent and Polident) had significantly higher flexural strength values than the other groups (p˂0.001) and were followed by Vertex and NextDent, while Polyamide and Harz had the lowest values. Polyamide and Harz denture base resins had significantly lower flexural strength values than conventional denture base resin (p˂0.001). Conclusion CAD‐CAM milled DBRs showed the highest flexural strength when compared with conventional compression‐molded or 3D‐printed DBRs, while 3D‐printed DBRs and polyamide showed the lowest flexural strengths.

Objective:The objective of this study was to compare the elastic modulus between milled, 3D printed and conventional compression moulded denture base resins (DBRs). Materials and methods: Three different types of DBRs were used: milled resin (pre-polymerized PMMA plates) ; a 3D printed resin (photopolymerized resin); and a polymethyl methacrylate (PMMA) heat cured resin (powder-liquid system). Thirty specimens have been constructed with specific dimensions (65mm x10mm x3mm) and divided into 3 groups (10 for each group) according to the type of DBR, Group I contained the milled DBR specimens, Group II contained 3-dimentional printed DBR specimens, and Group III contained conventional compression moulded DBR specimens. The elastic modulus of the 30 specimens were measured and calculated by universal testing machine using three-point loading test. Results: The elastic modulus of the milled group was significantly higher than that of the other 2 groups (P<0.05), while the elastic modulus of the compression moulded group was significantly greater than that of the 3D printed group (P<0.05). Conclusion: milled DBR show the highest elastic modulus when compared with conventional compression moulded or 3D printed DBRs, while 3D printed DBR shows the lowest elastic modulus.