Removable acrylic resin disk as a sampling system for the study of denture biofilms in vivo.

STATEMENT OF PROBLEM: The adhesion of microorganisms to a denture surface can result in denture stomatitis. PURPOSE: The purpose of this study was to evaluate denture biofilm in vivo using a new sampling system to gain a better understanding of plaque organization in Candida-induced denture stomatitis. Removable acrylic resin disks were used with self-adhesive paper disks to compare biofilm formation and retention efficacy of both sampling systems. MATERIAL AND METHODS: Twenty-one subjects with a complete maxillary denture were recruited, 12 with a clinical diagnosis of chronic denture stomatitis and 9 with a clinically healthy palatal mucosa. A custom-made autopolymerized 3.0-mm-diameter acrylic resin disk inlay was inserted in a cavity prepared within the intaglio surface of the maxillary denture in contact with either normal or inflamed mucosa. Next to the acrylic resin disk, a self-adhesive paper disk was placed for comparison of the 2 sampling techniques. Denture biofilms were collected within variable time periods of 1 hour to several months, and descriptive data were provided by means of scanning electron microscopy analyses. The method of retention and recovery of specimen disks were evaluated between both sampling techniques using a chi-square test to assess significant differences (alpha=.05). RESULTS: Early event features of denture biofilms showed differences in biofilm organization between the 2 sampling techniques but became subtler with increased time periods. Regardless of the sampling technique, interparticipant variations could be observed as to rate, microorganism density, and architectural pattern. In general, denture biofilm formation was increased when the sampling disks were localized in areas affected by denture stomatitis. CONCLUSION: The new sampling technique provides reliable information with controlled formation time of denture biofilm in its natural environment.

Reassessing the presence of Candida albicans in denture-related stomatitis.

OBJECTIVE: The aim of this study was to reevaluate the link between Candida albicans and denture-related stomatitis according to a modified Newton classification, which reflects the classic types of inflammation as well as the extent to which the tissue is affected. STUDY DESIGN: Two groups of denture wearers were evaluated for denture-related stomatitis. The presence and number of yeasts on the dentures, the identification of the Candida species present, and the amount of plaque coverage were determined. Putative risk factors were included in the study. Relations between these variables and stomatitis were analyzed statistically. RESULTS: According to Newton's classification, the presence of yeast on the denture was not linked to whether subjects had stomatitis. But with our classification, higher prevalence of yeast carriers, yeast colony number, and plaque coverage were found on the dentures of individuals with the most extensive inflammation, regardless of Newton type. Among risk factors evaluated, wearing dentures at night and smoking were associated with the most extensive inflammation. We also demonstrated that the presence of C albicans as well as the cohabitation of different Candida species was more frequent in denture-related stomatitis. The differences were statistically significant. CONCLUSIONS: Statistical analysis of microbiologic data from different denture-related stomatitis categories according to our modified classification showed that the presence of yeast on dentures was significantly associated with the extent of the inflammation, rather than with the Newton type. Our findings suggest that the inflammatory process of stomatitis favors the colonization of Candida. These results could have new implications for diagnosis and management of the condition.

Production and characterization of an in vitro engineered human oral mucosa.

The role of epithelial cells in oral pathologies is poorly understood. Until now, most studies have used normal or transformed epithelial cell monolayers, a system that largely bypasses oral mucosal complexity. To overcome these limitations, an engineered human oral mucosa (EHOM) model has been produced and characterized. Following histological and immunohistochemical analyses, EHOM showed well-organized and stratified tissues in which epithelial cells expressed proliferating keratins such as Ki-67, K14, and K19 and also differentiating keratin (K10). In this model, epithelial cells interacted with fibroblasts in the lamina propria by secreting basement membrane proteins (laminins) and by expressing integrins (beta1 and alpha2beta1). Cytokine analyses using cultured supernatants showed that cells in EHOM were able to secrete interleukins (IL) including IL-1beta and IL-8 and tumor necrosis factor alpha (TNF-alpha). Finally, cells in this engineered model were able to secrete different metalloproteinases such as gelatinase-A and gelatinase-B. In conclusion, using tissue engineering technology, we produced well-organized EHOM tissues. It is anticipated that this model will be useful for examining mechanisms involved in oral diseases under controlled conditions by modeling the interactions between mucosa and microorganisms in the oral cavity.