A comparative evaluation of soft denture liners

Statement of problems: Two potential problems commonly identified with a denture base incorporating a resilient liner are a failure of the bond between the acrylic resin and resilient liner material and colonization of Candida albicans over time. Aims: This in vitro experimental study evaluated the shear and compressive bond strength as well as colonization of Candida albicans of commonly available denture soft liners. Materials and methods: The denture liners investigated were acrylic resin-based heat-polymerized (Super soft) and auto-polymerized (Refit and Softliner) resilient liner. The resilient liners were processed according to manufacturers’ instructions. The soft liners specimens for testing colonization of Candida albicans (n=10) were 6×3 mm. The soft liner specimen for shear and compressive strength testing (n=5) were of 6 mm diameter and 3 mm thickness. Specimens shape and linear thickness were standardized. Specimens were stored for 48 hrs, 1 week and 2 week interval for incubation at 37C. The growth around and below the surface of the specimens were read as positive. Shear and compressive strength were measured in a universal testing machine at a crosshead speed of 20 mm/min and 2mm/min respectively. Student “t” test and ANOVA were used to analyze the data. Result: Results showed that with the increase in time for incubation of test materials with Candida albicans, the adherence property of the material was increased in heat-cured and auto-polymerized soft liners. There was significant difference in compressive and shear bond strength among different soft liners. ConclusionWithin the limitation of this in vitro study, specimens of soft liners shows equal number of growth of Candida albicans and significant difference in shear and compressive bond strength.