Bond strength of relined print and conventional denture base resins after aging

Abstract

Objectives: To compare the bond strength of printed and conventionally produced denture base resins to reline resins after being submitted to a physical-chemical aging process. Methods: Sixty specimens (10×10×3.3 mm) of two printed (V-Print Dentbase and Denture 3D+) and one conventionally produced (Probase Hot) denture base resins were relined with two acrylic resins: Ufi Gel Hard C and Probase Cold (n=10). The specimens were submitted to 1000 cycles of thermal fluctuations (5-55ºC) and 28 days of pH cycles using pH=3 (8 h/day) and pH=7 (16 h/day). Then, the shear bond strength was evaluated (1 KN; 1 mm/min), and the failure mode was classified as adhesive, cohesive, or mixed type. Data were analyzed with Kruskal-Wallis and t-tests (=0.05). Results: Bond strength values ranged from 8.9 to 21.5 MPa. No statistically significant (p=0.07) differences were found between the bond strength of the three denture base acrylic resins. The reline resin did not significantly (p=0.07) affect the bond strength of the two printed resins. However, relining the Probase Hot with Probase Cold yielded a higher bond strength (p<0.001) than with Ufi Gel Hard C. Only the Probase Hot-Ufi Gel Hard C group revealed 100% of failures classified as adhesive type. Conclusions: The two printed denture base resins obtained similar bond strength to conventionally produced denture base resin after being submitted to thermal and chemical aging