title: Denture disinfection by microwave energy: influence of Candida albicans biofilm.
abstract: OBJECTIVE
  This study evaluated the influence of the area of Candida albicans biofilm on denture disinfection by microwave energy.
  
  
  METHODS
  Candida albicans biofilm was allowed to form for 72 h on resin discs, and three small coverage or seven large coverage discs were placed onto the palatal surface of sterile maxillary dentures. Each denture was immersed in 200 ml distilled water and individually irradiated at a power of 450, 630 or 900 W for different time intervals (1, 2 or 3 min) (n = 6). The effectiveness of disinfection was evaluated by counting the residual cells. The data were analysed by anova and Tukey's HSD test (α = 0.05). Pearson's correlation test was performed to determine the correlation between effectiveness of sterilisation and temperature.
  
  
  RESULTS
  Dentures with a larger area of biofilm demanded a longer irradiation exposure to achieve disinfection (p < 0.001), irrespective of power setting, and in this time no yeast growth was detected. Dentures with small areas of biofilm were disinfected after 1 min at 900 W and 2 min at 450 or 630 W. A positive correlation was found between water temperature and effectiveness of disinfection (r = 0.6170; p < 0.001).
  
  
  CONCLUSIONS
  The C. albicans biofilm area influenced disinfection by microwave energy; therefore dentures with larger biofilm areas required longer irradiation exposure to be disinfected.
authors.affiliation: Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Campinas, São Paulo, Brazil.
authors.forename: Plínio Mendes
authors.initials: PM
authors.lastname: Senna
authors.forename: Wander José
authors.initials: WJ
authors.lastname: da Silva
authors.forename: Altair Antoninha Del Bel
authors.initials: AA
authors.lastname: Cury
mesh_terms: D018441:Biofilms / Q000528:radiation effects*; D002176:Candida albicans / Q000528:radiation effects*; D015169:Colony Count, Microbial; D044622:Dental Pellicle / Q000382:microbiology; D003778:Dentures / Q000382:microbiology*; D004203:Disinfection / Q000379:methods*; D006801:Humans; D007101:Immersion; D008422:Materials Testing; D008872:Microwaves / Q000627:therapeutic use*; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011829:Radiation Dosage; D016037:Single-Blind Method; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D019904:Polymethyl Methacrylate