In-vivo and In-vitro Studies for Analysis of Mastication in Complete Denture Wearers with Resilient Denture Liners

Abstract

Purpose : This study aimed to comprehensively evaluate mastication in individuals wearing dentures with permanent resilient liners. Materials and Methods : Of the 53 patients who were randomly allocated into two groups, 26 and 27 patients received mandibular complete dentures with an acrylic resilient liner (ARL) and conventional acrylic resin (CAR), respectively ; 24 patients who had previously received mandibular complete dentures with a silicone resilient liner (SRL) served as a historical control. Mandibular movement during mastication was analyzed in 12, 10, and 10 age- and gender-matched subjects selected from the SRL, ARL, and CAR groups. Dynamic viscoelasticity and Shore A hardness tests were carried out to verify the relationship between the clinical trial findings and the mechanical properties of SRL, ARL, and CAR. Results : The masticatory performance of the SRL group was significantly higher than that of the ARL and CAR groups. Compared to the CAR and ARL groups, the SRL group showed longer occluding time in the initial, middle, and final phases. There were no significant differences in the maximum bite force among the three groups. The tanδ value of ARL was higher than those of SRL and CAR. The shear storage modulus G' and shear loss modulus G'' of CAR were higher than those of ARL and SRL. The hardness value of ARL was significantly greater than that of SRL. Conclusion : The prolonged occluding time due to the softness of resilient denture materials may improve the masticatory performance of complete denture wearers.