Setting and stress relaxation behavior of resilient denture liners.

STATEMENT OF PROBLEM: Resilient denture liners are widely used for the patients who are not comfortable with correctly made conventional hard-based dentures because of thin and relatively nonresilient mucosa or severe alveolar resorption. There are several materials used for denture liners and the efficacy in their use is influenced by their viscoelastic properties. PURPOSE: This study evaluated the setting behavior and viscoelastic properties of various types of resilient denture liners and the changes in viscoelasticity with the passage of time. MATERIAL AND METHODS: Four types of resilient denture liners were used. Setting behavior of 5 autopolymerizing materials was evaluated with an oscillating rheometer. Stress relaxation tests were conducted to evaluate the viscoelastic properties of 9 materials and changes that occurred over time by means of Maxwell model analogies. RESULTS: Significant differences were found in the setting behavior of the autopolymerizing materials. The acrylic resin and fluoroethylene materials demonstrated viscoelastic properties and the silicone and polyolephin materials were found to be elastic. The acrylic resin materials exhibited the greatest changes in viscoelastic properties over time when compared with silicone, polyolephin, and fluoroethylene materials. CONCLUSIONS: The results suggest that it is important to select denture liner materials according to clinical situations because of the wide ranges of setting behavior, viscoelastic properties, and durability over time.