JOURNAL OF PROSTHETIC DENTISTRY THE

Vol. 99 No. 2      FEBRUARY - 2008

ISSN: 0022-3913      UBIC: 171

RESUMEN

Statement of problem: 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 a loss of resiliency of the resilient liner material over time. Purpose: This investigation evaluated the effect of storage duration on the tensile bond strength and hardness of acrylic resin- and silicone-based resilient liners that were either heat- or autopolymerized onto denture base acrylic resin. Material and methods: The denture liners investigated were a definitive acrylic resin-based heat-polymerized (Vertex Soft), interim acrylic resin-based autopolymerized (Coe-Soft), definitive silicone-based heat-polymerized (Molloplast-B), and definitive silicone-based autopolymerized (Mollosil Plus) resilient liner. The resilient liners were processed according to manufacturers' instructions. The resilient liner specimens for tensile bond strength testing (n=10) were 10 x 10 x 3 mm and were processed between 2 polymethyl methacrylate (PMMA) (Meliodent) blocks (40 x 10 x 10 mm). The resilient liner specimens for hardness testing (n=10) were 20 mm in diameter and 12 mm in height. Specimen shape and liner thickness were standardized. Specimens were stored for 1 day, 1 week, or 1, 3, or 6 months in water at 37°C. Tensile bond strength was measured in a universal testing machine at a crosshead speed of 20 mm/min, and hardness was measured using a Shore A durometer. Two-way ANOVA and Tukey HSD tests were used to analyze the data ( =05). Results: The results indicated that there were significant differences both in the hardness and bond strength values of resilient liner materials. The definitive silicone-based heat-polymerized (Molloplast-B) resilient liner had significantly higher bond strength and lower hardness values than the others. Prolonged exposure to water produced significantly higher hardness values and lower bond strength values. Conclusions: Within the limitations of this in vitro study, specimens of resilient liners immersed in water demonstrated significantly (P<. 001) lower bond strength values and higher hardness values over time. (J Prosthet Dent 2008;99:153-159)

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