Candidal Adhesion to an Oral Obturator PMMA Resin Incorporated with Vanillin

Abstract

An oral obturator is a prosthesis used for a variety of dental conditions to help patients regain their abilities after trauma, surgeries, or having congenital defects. It is commonly made from polymethyl methacrylate (PMMA) resin. Despite that, this resin appliance can give rise to a condition for microbial adhesion and colonization on the resin surface itself and the mucosa beneath. This can place patients at a greater risk of infection. Oral infections caused by Candida species are found to be more common, particularly in immunologically compromised patients and those with other conditions in the oral cavity that often include oral prosthetic appliances. Obturator resin incorporated with vanillin has been produced and shown to have antimicrobial properties against some bacteria and yeasts. The purpose of this study was to determine the adhesion of candida to vanillin incorporated obturator resin. The auto-polymerized resin samples (Orthocryl® EQ, Dentaurum, Germany) were prepared with different concentrations of vanillin incorporation (0.1%, 0.5%, and 1% vanillin w/w). All samples were coated with sterile saliva and incubated at 37 °C for 60 min. The adhesion assay was done with four species of candida (C. albicans ATCC 10231, C. krusei ATCC 14243, C. glabrata ATCC 15126, and C. tropicalis ATCC 1369). The resin samples were placed in a 24-well plate containing 107 CFU/mL of candidal suspension and incubated in a shaking incubator (120 r/min) at 37°C for 2 h for candidal adhesion. Non-adherent cells were removed by washing with phosphate buffer saline (PBS) solution. The remaining adherent cells on the obturator resin surface were quantified by the WST Microbial Cell Counting Kit (Dojindo Molecular Technologies, USA). The Kruskal-Wallis test, followed by Dunn’s method, was applied for statistical analysis. The results showed that the addition of 0.5% and 1% w/w vanillin to oral obturator PMMA resin could significantly reduce the adhesion of all Candida species except that of C. krusei, for which a reduction effect was observed at 1 % vanillin. The percentage reduction of candidal adhesion on obturator resin varies from 9% to 35%, which was highest on C. albicans, followed by C. glabrata (24%), and C. tropicalis (21%). No reduction effect was observed at 0.1% vanillin on all Candida species. In conclusion, vanillin-incorporated oral obturator resin displayed a reducing effect on the adhesion of all tested Candida species. C. albicans was the most susceptible species, while C. krusei was the most resistant. The mechanisms of action could possibly be the aldehyde group of the vanillin structure that causes cell membrane damage, interferes with DNA, RNA, and protein synthesis, as well as enzyme activities within the yeast cell. This newly developed PMMA resin could be valuable for the prevention or as an adjunctive treatment for controlling oral candidal infection among patients who use oral obturators.