The effect of gastric acid on the bonding of 3D printed and CAD/CAM denture acrylics to denture teeth.

The purpose of this study was to compare the shear bond strength (SBS) of denture base resin (DBR) and dental materials produced by different methods and to investigate the effect of artificial gastric acid on bond strength. Heat-polymerized, subtractive (CAD/CAM-milled) and additive (3D printing) DBR-teeth combinations were investigated. 5 × 5 × 2 mm teeth, 10Ø, 2 mm high base samples were produced according to the manufacturer's instructions. The teeth specimens were bonded with the same type of DBR and immersed in artificial gastric acid solution. They were stored in an incubation device at 37 °C for 96 h. The SBS test was performed on a universal testing machine. Statistical analysis of the results was performed using ANOVA and Games-Howell (α = 0.05). The mean SBS was highest in the 3D printed group (15.08 ± 4.25 MPa). This was followed by heat-polymerized (12.90 ± 3.00 MPa ), then CAD/CAM-milled group (6.57 ± 2.01 MPa ). The manufacturing method significantly affected the SBS (P < 0.001), but artificial gastric acid did not significantly change the SBS of any group (P = 0.488). The 3D printed group showed the highest bond strength. 3D printing method can be used safely in patients with gastroesophageal reflux disease (GERD).