AbstractsBiology & Animal Science

Colonisation of acrylic denture fitting surfaces by Candida species

by Nicholas James Knight

Institution: University of Otago
Year: 0
Keywords: Candida; C. albicans; C. tropicalis; C. krusei; Denture; Acrylic; Methacrylate; Fungi; Fungal; Adhesion; Colonisation; Colonization; Oral; Mucosal; Mucosa
Record ID: 1317490
Full text PDF: http://hdl.handle.net/10523/5126


Denture-associated candidal infection is usually painless and localised to a relatively small area of the mouth but may lead to serious complications such as systemic yeast infection in susceptible patients. This includes those who have a compromised immune system, particularly the elderly. One of the factors predisposing to denture-associated candidal infection is denture-induced trauma, where an ill-fitting denture creates a more favourable environment for the growth of the yeast. In this research project, we investigated the patterns of the colonisation by Candida spp. of the oral mucosal and acrylic denture fitting surface in patients with ill-fitting dentures and following delivery of new dentures. Sixteen edentulous patients attending the Faculty of Dentistry, University of Otago, for fabrication of new complete dentures were enrolled in the study; ten of these participants completed the study. Saliva and mucosal swab samples were collected from each participant and incubated on CHROMagar Candida plates. CHROMagar Candida impressions were captured from the fitting surfaces of boxed maxillary complete dentures. The numbers of colony forming units (CFU) of yeast present in the saliva samples and on the dentures were counted and the yeast species presumptively identified by their colony colour. Sampling was repeated following delivery and review of new dentures after 1 month, 3 months and 6 months. Before delivery of new dentures, 8 of the 10 participants had yeast in their saliva at concentrations ranging from 20-4,280 CFU/ml. Half the participants had C. albicans in their saliva and 7 only had one species present, saliva from one participant contained 3 species. Only one participant had yeast in their saliva 1 month after delivery of their new denture, but this increased to 4 participants after 6 months. The old dentures of 6 of the participants were colonised with yeast, mostly C. albicans but C. krusei was detected on 4 of the old dentures. After 1 month only 2 dentures were colonised, but after 6 months 6 dentures were colonised with a variety of species. The new dentures were colonised by C. albicans and C. tropicalis, but after 6 months C. krusei was also present. It was concluded that the provision of new dentures reduced the number of yeast in the saliva and on the denture fitting surface and reduced the Candida species diversity of the saliva and denture fitting surface for three months. These results suggest that C. tropicalis and C. albicans are early coloniser and C. krusei is a late coloniser of the denture fitting surface.