Evaluation of Bond Strength of Surface Conditioned Artificial Teeth with Modified and Valplast Denture Bases With Aging

Background: bond failure of acrylic and porcelain teeth represents primary clinical disadvantages of partial and complete denture services provided to the patient. The aims of the study were to investigate the tensile and shear bond strength of two types of denture bases (heat cured reinforced with 5% ZrO2nano-fillers and valplast) with (acrylic and porcelain) teeth after ridge lap conditioning and using aging. The measurements were used for comparison with traditional denture base. Materials and methods: denture bases reinforced with nano ZrO2 and valplast were bonded to acrylic and porcelain teeth. Samples were divided for shear and tensile strength. Each contains 5 samples. The ridge lap surface were conditioned by different treatments and then subjected to aging. Tensile and shear bond strength measured by instron testing device. The results were organized and evaluated by using analysis of variance (f-test) and t-test for comparison between subgroups. Results: artificial teeth bonded to nano reinforced denture base required higher tensile and shear force to separate when compared with traditional heat cured and valplast resins. The mode of failure where cohesive either in the denture base or in the tooth itself when compared with valplast resin. Acrylic teeth conditioned with turpentine and porcelain with hydrofluoric acid express higher tensile and shear bond compared with unconditioned teeth. Aging sustained damaging effects on the bond strength of artificial teeth bonded to valplast denture base in compared with nano reinforced and conventional heat cured. Conclusions: tensile and shear bond strength of artificial teeth enhanced by the reinforcement of the resin with nano-sized fillers and by conditioning of the teeth ridge lap using chemical agents, making the bond stronger and durable to withstand fluctuated oral conditions.