Effect of storage duration on tensile bond strength of acrylic or silicone-based soft denture liners to a processed denture base polymer

Abstract

Objective: To investigate the effect of storage duration on the tensile bond strength of acrylic and silicone-based denture base materials with liners either heat-cured or auto-cured.

Material and methods: The denture liners investigated were Vertex soft (acrylic-based, heat-cured), Coe soft (acrylic-based, auto-cured), Molloplast-B (silicone-based, heat-cured), and Mollosil plus (silicone-based, auto-cured). The soft liner specimens were 10 x 10 x 3 mm and were processed between two PMMA blocks. They were tested following immersion in water at 37 degrees C for 1 day, 1 week, and 1, 3, and 6 months. Tensile bond strength was measured using a universal testing machine (Testometric Micro 500) at a crosshead speed of 20 mm/min (n = 10 specimens per experimental group). Multiple ANOVA and Tukey HSD were used to analyse the data at a pre-set alpha of 0.05.

Results: The results indicate that the tensile bond strength of acrylic-based soft liners is greater than that of silicone-based materials. The bond strength of all lining materials decreases with storage duration; the decrease being greatest for the acrylic-based soft liners. The decrease in bond strength of the auto-cured materials is greater than that of the heat-cured products.

Clinical significance: Comparison of the materials in this study indicates that the silicone-based, heat-cured soft liner is superior, based on the tensile bond strength property. Use of silicone-based, heat-cured soft liners may provide better clinical success over a long period. These laboratory results need to be verified by clinical testing.