Chemo-Mechanical Approach to Improve Repair Bond Strength of Denture Teeth

Detachment of acrylic teeth from denture base material is a common complication in dentistry which accounts for 26-30% of repair cases. This study aimed to evaluate the effect of alumina-blasting, silane coupling agent, and thermal cycling on the shear bond strength of repaired teeth to denture base.

Specimens (140) of repaired teeth to denture bases were fabricated and divided into 14 groups: 7 groups before thermal cycling and 7 groups after thermal cycling (n = 10). The groups were divided according to surface treatment into no treatment (control), treatment of the base (B), the tooth (T), or both (BT). Each group was further subdivided according to the surface treatment method into alumina-blasting or alumina-blasting and silane coupling agent. After treatment, acrylic discs and teeth were fixed in a jig, and the repair procedure was done. Half the specimens were thermally cycled. Shear bond strength was measured using a universal testing machine. ANOVA and Tukey HSD tests were performed at α = 0.05.

Surface treatment significantly improved the bond strength compared to the control group (P < 0.001). Comparing surface treatments, alumina-blasting with silane coupling agent treatment resulted in significantly higher strength compared to alumina-blasting alone (P < 0.001). The BT group treated with alumina-blasting and silane coupling agent showed the highest significant shear bond strength (23.91 ± 0.96 MPa) (P < 0.001). Significant drop in strength value was observed in all groups after thermal cycling (P < 0.004) except the BT group treated with alumina-blasting (P=0.096).

Surface treatment using alumina-blasting with silane coupling agent for denture base and tooth increased repair strength.