A comparative in vitro study of two denture cleaning techniques as an effective strategy for inhibiting Candida albicans biofilms on denture surfaces and reducing inflammation.
OBJECTIVE
Candida albicans is the predominant oral yeast associated with denture-induced stomatitis, and with an increasing population of denture wearers its incidence is increasing. Maintaining good oral and denture hygiene, through chemical and/or mechanical intervention, is essential to reducing this disease. The aim of this study, using a robust adherent C. albicans cell model system, was to evaluate and compare the efficacy of a novel denture cleanser to the efficacy of a commonly used dentifrice coupled with brushing.


METHODS
Four C. albicans strains isolated from individuals diagnosed as having denture-induced stomatitis, were adhered to denture acrylic resin sections (1 cm(2) by 1 mm thickness) and after 4 hours of growth, challenged daily sequentially for 4 days with a denture cleanser (Polident) or intermittently with denture cleanser (day 1), then dentifrice (Colgate Cavity Protection Toothpaste) and brushing (days 2 and 3) and denture cleanser (day 4). Colony forming units were evaluated for each treatment, as were the levels of regrowth. Scanning electron microscopy (SEM) was also performed. Microbial susceptibility testing and time-kill studies were performed on biofilms. A coculture model was also used to assess interleukin-8 (IL-8) production from treated biofilms.


RESULTS
It was shown that sequential treatment with the denture cleanser killed and inhibited regrowth each day. Intermittent treatment showed that viable C. albicans biofilms were only retained rather than being dispersed, which could be visualized by SEM. Time-kill studies demonstrated that the novel denture cleanser was highly active and killed quickly, unlike the dentifrice. IL-8 was expressed in greater levels in 24-hour biofilms than in 4-hour biofilms, but treatment with denture cleanser reduced IL-8 output.


CONCLUSIONS
The data indicate that maintaining good oral health for denture wearers requires daily use of a denture cleanser rather than an alternating regimen. The inability of the denture cleanser to sterilize during intermittent treatments demonstrates the difficulty in controlling established biofilm. Moreover, the presence of mature biofilm may result in high levels of inflammation, but this can be controlled through denture cleansing.
Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK. gordon.ramage@glasgow.ac.uk
Gordon
G
Ramage
Adriana
A
Zalewska
Donald A
DA
Cameron
Leighann
L
Sherry
Colin
C
Murray
Mary Beth
MB
Finnegan
Zvi G
ZG
Loewy
Daryll C
DC
Jagger
D000180:Acrylic Resins; D018441:Biofilms / Q000187:drug effects; D002176:Candida albicans / Q000187:drug effects*; D002180:Candidiasis, Oral / Q000517:prevention & control*; D018920:Coculture Techniques; D003802:Dentifrices / Q000494:pharmacology; D003819:Denture Bases / Q000382:microbiology*; D003820:Denture Cleansers / Q000494:pharmacology*; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis; D009910:Oral Hygiene / Q000379:methods; D013282:Stomatitis, Denture / Q000382:microbiology / Q000517:prevention & control*; D014099:Toothbrushing
D000180:Acrylic Resins; D003802:Dentifrices; D003820:Denture Cleansers; D016209:Interleukin-8