Denture Base PMMA Resin Containing Vanillin Inhibits Biofilm Formation of Bacteria Associated with Malodor

Abstract

Dentures are prosthetic device made of polymethyl methacrylate acrylic (PMMA) resin generally used by elderly people to replace their real teeth. However, the porosity and surface irregularities of acrylic resin are undesirable aspects of the denture base that can support colonization of oral microorganisms on the denture surface, particularly those associated with malodor. Oral malodor is a common and upsetting situation frequently found in denture wearers due to inadequate denture cleaning. A large number of strategies had been employed to minimize the potential bacterial pathogens, including mechanical brushing and using chemical agents. Therefore, we have developed denture PMMA resin containing vanillin and evaluated antimicrobial potential against four species of bacteria related to oral malodor. Denture base resin samples were prepared with dimensions of 10 mm x 10 mm x 1 mm. according to the amount of incorporating vanillin concentrations (0.1%, 0.5% and 1.0% w/w) and coated with saliva. Then, the biofilm formation of four species of bacteria (Porphyromonas gingivalis ATCC 33277, Aggregatibacter actinomycetemcomitans ATCC 33384, Fusobacterium nucleatum ATCC 25586, and Actinomyces viscosus ATCC 19246) was performed on resin samples in anaerobically condition for 48-72 h. Denture resin sample without vanillin was prepared in the same way and used as a control. The quantity of vital biofilm was assessed by WST Microbial Cell Counting Kit (Dojindo Molecular Technologies, USA). Kruskal-Wallis test followed by Dunn’s method were applied for statistical analysis. The results showed that in the groups of 0.5% and 1.0% w/w vanillin, significant decreases of biofilm mass were observed in all tested bacteria (P. gingivalis, A. actinomycetemcomitans, and F. nucleatum) compared with controls, except for A. viscosus. Approximately 30% to 38% bacterial biofilm reduction was demonstrated at 1.0% w/w vanillin on three species of bacteria, whereas 7% to 27% biofilm decreases were observed at 0.5% vanillin. No significant biofilm reduction was observed in A. viscosus. This conforms to our previous studies which revealed the antimicrobial properties of denture PMMA resin containing vanillin on respiratory pathogens and oral yeast. Denture base resin consisting of vanillin may be considered as a promising dental appliance for the use to prevent or solve the problem of oral malodor in patients who wear dentures.