A comparison of the shear bond strength between denture teeth and denture base resins manufactured either conventionally or with a 3D printer

Statement of problem. Limited information is available on the shear bond strength (SBS) between denture teeth and denture base resins fabricated using a stereolithography (SLA) 3-dimensional (3D) printer. Purpose. The purpose of this in vitro study was to evaluate the SBS between denture teeth and the denture base resins produced with the conventional method and with a 3D printer.Material and methods. Conventional or 3D printed denture teeth were included in the study. The denture base resins were manufactured either conventionally or with a 3D printer. Four subgroups were tested: conventional teeth-conventional base resin (CT-CB), conventional teeth-printed base resin (CT-PB), printed teeth-conventional base resin (PT-CB), and printed teeth-printed base resin (PT-PB). The maxillary molars were combined with & empty;5x2.5-mm-cylindrical denture base resin. Shear bond testing was performed by applying a parallel force to the denture teeth-denture base resin interface by using a blade-edge chisel with a crosshead speed of 1 mm/min until failure occurred. SBS and elastic modulus (EM) were recorded. One-way ANOVA followed by the Dunnett T3 post hoc test was used for the statistical analysis (alpha=.05). The failure modes of the specimens were also analyzed.Results. A statistically significant difference (P<.05) was found between the evaluated groups for the SBS and EM values. PT-PB showed the highest SBS value (15.4 +/- 2.7 MPa), and CT-PB showed the lowest (0.9 +/- 0.7 MPa). The PT-CB group showed the highest EM value (62.74 +/- 20.80 GPa), and the CT-PB group showed the lowest (29.46 +/- 28.40 GPa). The CT-CB and CT-PB specimens showed mostly adhesive failure; none of the PT-PB specimens showed adhesive failure.Conclusions. Three-dimensional printing led to a better bond between the denture teeth and the denture base resin compared with the conventional method. Although these findings need to be supported by clinical studies, the use of 3D printers is appropriate in the production of denture teeth and denture bases.