In Vitro Evaluation of Resilient Liner and Hard Denture Liner on the Retentive Force

Purpose: To clarify the relationship between the retention force and saliva viscosity for resilient denture liners. Methods: Tensile tests were performed using a simple model to compare the retention force of two commercially available resilient denture liners（S OFRELINER T OUGH M EDIUM and S OFRELINER T OUGH S UPER S OFT ）and a hard denture relining material （T OKUYAMA R EBASE III N ORMAL ）. Retention force measurements were conducted with three intervening liquids of different viscosities and repeated 10 times. The measured retention force and viscosity of the intervening liquid were compared with two-way ANOVA. The statistical significance was P < 0.05. Post-hoc Bonferroni multiple comparison tests were used to analyze significant results. Results: The saliva viscosity and relining material significantly influence denture retention. When purified water was used as an intervening liquid, significant differences were observed between all groups, and the S OFRELINER T OUGH S UPER S OFT material showed the highest retention force. Conclusions: Relining a denture with a silicone-based resilient denture liner increases the retention force of the denture, and is particularly effective when the fluid viscosity is high.