Evaluation of adherence of Candida albicans to differently manufactured acrylic resin denture base materials.

Statement of problem: Though computer-aided design and computer-aided manufactured (CAD-CAM) denture bases have become popular, evidence on the ability of C. albicans cells to adhere to these denture bases is lacking.

Purpose: The purpose of this in vitro study was to evaluate the adherence of Candida albicans to differently manufactured acrylic resin denture bases.

Material and methods: Acrylic resin disks were fabricated using a total of 6 different fabrication methods (compression molding, injection molding, CAD-CAM milling, and rapid prototyping on 3 different printers with 3 different resins). Each material was evaluated for adherence of C. albicans using 2 different experimental methods - suspension in inoculated tryptic soy broth (TSB) or placed onto a uniform lawn of C. albicans on tryptone soya agar (TSA) with 5% sheep's blood. Attached cells were quantified by spiral plating and then used to re-inoculate sterile plates. Logarithmic transformation was completed to normalize data. For the broth suspension, the Kruskal-Wallis test was used to identify any differences between the 6 specimen types in terms of recovery, and the Dunn test was used for post hoc analysis. For the microbial lawn experiment, 1-way analysis of variance (ANOVA) and then the Tukey Honestly Significant Difference (HSD) post hoc test were used.

Results: Statistically significant differences were found between the numbers of adherent cells based on manufacturing method and between experimental designs (P<.05). All resins demonstrated growth with re-inoculation.

Conclusions: Though statistical significance was noted, neither experimental technique demonstrated what is likely a clinically significant preferential binding to any particular resin surface. Attached Candida cells are effective carriers of pathogens to uninfected surfaces. Further studies are indicated for potential virulence factors and differences in printed resins.