| Objective To evaluate the effect of denture base resin surface pretreatmentwith chemical etchants on microleakage and bond strength between silicone-basedresilient liner and denture base resin. The initial flexural strength of denture base resinafter surface pretreatment was also examined. Methods Thirty-six polymethy1methacrylate(PMMA) denture base resin blocks (30mm×30mm×2mm) wereprepared and divided into three groups: group acetone, group methylmethyacrylate(MMA) and group control. Subsequently, a2mm silicone-basedresilient liner was applied between every two blocks. After5000cycles in the thermalcycler (5and55℃), they were immersed in the131I solution for24hours and γ-raycounts were measured. Another36PMMA resin blocks (30mm×10mm×7.5mm)were prepared. The blocks were divided into three groups and treated as mentionedabove. A3mm silicone-based resilient liner was applied between every two blocks.After5000thermal cycles, tensile bond strength of the sample was measured in auniversal testing machine. Another18PMMA resin blocks (65mm×10mm×3.3mm)were prepared. They were divided into3groups and treated in the same way. After anadhesive was applied, the flexural strength was measured with three-piont flexuraltest. Results Two experimental groups showed lower microleakage (520.0±562.2and493.5±447.9) and higher tensile bond strength[(1.5±0.4) and (1.4±0.5) Mpa]than the group control [microleakage:(1369.5±590.2); tensile bond strength:(0.9±0.2) Mpa, P<0.05]. There was no statistically significant difference between group acetone and MMA in microleakage and tensile bond strength(P>0.05). Therewas no statistically significant difference in flexural strength among the three groups(P>0.05). Conclusions Treating the denture base resin surface with acetone andMMA decreased the microleakage, increased the bond strength between the twomaterials and did not make the initial flexural strength of denture base resin decline. |
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