Evaluating Tooth–denture Base Bonding Performance in Conventional and CAD/CAM Denture Bases with Different Surface Treatments: An In Vitro Study

Abstract

The integrity of the bond between acrylic denture teeth and denture base resin is essential for the longevity and clinical success of complete dentures. However, limited evidence exists regarding the influence of CAD/CAM fabrication methods and surface treatments on the performance of this interface. A total of 42 acrylic canine denture teeth (21 left and 21 right) were fabricated using either heat-cured acrylic resin or the CAD/CAM production method. Each group of 21 specimens was further divided into three subgroups (n = 7), which received one of the following surface treatments: no treatment, creation of a diatoric recess on the ridge lap surface, or creation of a diatoric recess combined with the application of a bonding agent (methyl methacrylate). Maximum load and mode of failure were evaluated using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed using two-way Analysis of Variance (ANOVA) followed by Tukey post hoc tests at a significance level of p < 0.05. The Diatoric + Monomer Heat-Cure group exhibited the highest mean maximum load, whereas the CAD/CAM groups showed lower values. Two-way ANOVA revealed significant effects of production method ( p < 0.001) and surface treatment ( p = 0.036), while no significant interaction was observed ( p = 0.066). Tukey post hoc analysis showed no significant pairwise differences between treatment groups ( p > 0.05). The findings indicate that the maximum load sustained at the tooth–denture base interface is influenced by both fabrication method and surface treatment. Conventional heat-cured specimens generally demonstrated higher maximum load values than CAD/CAM specimens, while the combination of diatoric preparation and methyl methacrylate application produced the most favorable interface performance. Conventional denture bases demonstrated higher maximum load values than CAD/CAM-milled bases. Surface treatment showed a significant overall effect; however, no significant pairwise differences were found between treatment groups. Further studies with larger sample sizes are needed.