Strength testing of the relation between plate dentures and materials for making soft liners

Introduction. In clinical practice, the loss of adhesion between the denture base resin and reliner might cause the loss of material softness, water sorption, bacterial colonization and functional failure of the prosthesis. Aim. This study evaluated the effect of immersion on tensile bond strengths of four soft relining materials to a denture base acrylic resin. Material and methods. Four soft lining materials were bonded to heatpolymerized acrylic resin according to the manufacturers' directions. Forty specimens for bond strength test (10 for each liner type) were fabricated. Half of them (control group; n=5) were tested immediately after the fabrication. The other twenty specimens were stored in water at 37°C (test groups; n=5) for one week and then tested. Results. Bond strength of samples right after the fabrication is significantly higher in cases of the samples with silicone elastomer base reliner compared to the samples with soft acrylic base. Bond strength of soft reliners to a denture base resin increases after storing the samples in a water bath for one week at 37°C. Conslusion. Higher increment of tensile bond strength appeared for silicone elastomers in comparison with soft acrylic resins. There were no changes of failure mode except for GC Reline Soft application with the lowest tensile bond strength increment