Adhesion and mixed biofilm formation of Candida albicans and Candida glabrata on two types of soft denture liners and one heat-polymerized denture base resin: effect of roughness and surface free energy

Abstract

In oral rehabilitation with removable dentures, the use of soft liner materials, which may be silicone-based or acrylic-based, is often required. These denture liners may have different surface characteristics, which can influence the colonization process by Candida species and, therefore, the occurrence of denture stomatitis. Although Candida albicans is considered the main etiological agent of this disease, non-albicans species, among them Candida glabrata, have also been isolated. There is little information on the effects of surface characteristics of soft liners on the adhesion and biofilm formation of C. Albicans and C. glabrata, and the influence of these characteristics on adhesion and mixed biofilm formation of the two species have not been investigated. The aim of this study is to evaluate the influence of surface roughness and surface free energy of two soft liners, one silicone-based and one acrylic-based, and a heat-polymerized denture base acrylic resin on the initial adhesion and mixed biofilm formation of C. Albicans and C. glabrata. For these purposes, specimens (13.8 X 2 mm) of each material will be prepared according to the manufacturer's instructions. Standardized yeast suspensions (1x107 cells/mL) of the two species (C. Albicans and C. glabrata) will be placed on the specimens in culture plates and incubated for 90 minutes (adhesion phase) or 48 hours (biofilm formation) at 37 ° C. The initial adhesion and biofilm formation will be evaluated by counting the colony-forming units (CFU/mL). The results (CFU/mL) for each material, obtained in the adhesion and biofilm formation assays will be statistically analyzed and discussed. Furthermore, analyzes of materials' surfaces and microorganisms, after the adhesion phase and mixed biofilm formation, will be performed using scanning electron microscopy (SEM).(AU)