COMPARATIVE EVALUATION OF TENSILE BOND STRENGTH AND GAP WIDTH BETWEEN SILICONE BASED SOFT LINER AND HEAT-POLYMERIZED, LIGHT POLYMERIZED AND INJECTION-MOLDED PERMANENT DENTURE BASE MATERIALS.

Denture liners are polymers used on the intaglio surface of the denture. Adhesive failure can create environment for bacterial growth, staining, and failure of lining materials.Hence, the integrity of the junction needs to be evaluated because two materials polish differently.Therefore, this study compares the tensile bond strength and gap width between soft liner to heat-polymerized, injection-molded and light polymerized acrylic resins. Materials and Methods:-Ten dumbell shaped specimens for tensile bond test and square shaped specimens for gap width were fabricated with the metal mold. Putty index of dumbell shaped mold with the rectangular die in centre and two metal blanks were made. The specimes were placed in the index, adhesive was applied onto the bonding surface and soft liner was added. Tensile bond strength was determined in universal testing machine and gap width was observed under scanning electron microscope.Specimens were divided into 3 groups for tensile bond test and for gap width: T1, G1 heat-polymerizing; T2, G2 injection-molded; T3, G3 light activated denture base resins.Statistical analysis of the obtained data was done by ANOVA and post-hoc Tukey?s test. Results:-Therewas significant difference in the tensile bond strength among the three groups (p<0.05), and the mean gap width was not significant between G1 and G3 group and highly significant value was seen among G1 and G2; G2 and G3 groups (p<0.05). Conclusion:-Mollosil B bonds best with heat-polymerized denture base material and least gap with between denture base and soft liner.