In-vitro study of the fracture resistance of denture base resin with resilient reline material

Purpose: This study aimed to analyze the fracture resistance of denture base resins relined with either a conventional rigid resin or a new resilient resin. Materials and Methods: Two types of test plates were fabricated by relining the base resin (Acron) with a conventional rigid resin (Tokuso Rebase, TR) or a newly developed relining resin (Tokuyama Rebase II, RII). The specimens were divided into three groups (n=10) according to the number of thermo-cycles applied (0, 15,000, and 30,000), and were subjected to three-point flexural test. Mean flexural strength, elastic modulus, and the destruction energy of each group were statistically analyzed by one-way analysis of variance with Fisher’s PLSD at α=0.05. Results: RII showed higher flexural strength than TR, and the difference reached in the 30,000 thermo-cycling group (p<0.05). TR showed significant reduction of elastic modulus after 30,000 thermo-cycling (p<0.05). On the other hand, RII showed no significant difference between the elastic modulus before and after thermo-cycling (p>0.05), though the elastic modulus of RII is lower than that of TR. The destruction energy of TR was significantly less than that of RII (p<0.05) after thermo-cycling. Conclusion: The results of this study demonstrated that a new relining resin, Tokuyama Rebase II, provides higher elasticity, resilience, and durability than Tokuso Rebase. Destruction energy was indicated to express comprehensive proof strength against mechanical force and serve as an effective parameter in the evaluation of relining materials used for repair and adjustment of fractured or poor-fit denture bases. (Int Chin J Dent 2007; 7: 53-58.)