Denture disinfection by microwave irradiation: a randomized clinical study.
OBJECTIVE
This study evaluated the clinical effectiveness of two exposure times of microwave irradiation on the disinfection of complete dentures.


METHODS
Biofilm samples were collected from dentures of 30 patients, who were randomly divided into two experimental groups of 15 subjects each: Group 1-patients had their maxillary denture microwaved for 3 min (650W); Group 2-patients had their maxillary denture microwaved for 2 min (650W). Denture biofilm samples were taken with swabs, before (left side surfaces) and after (right side surfaces) microwave irradiation. All microbial material was plated on selective media for Candida spp., Staphylococcus spp., mutans streptococci and a non-selective media. After incubation (48 h/37 degrees C), the number of colony-forming units (cfu/mL) was counted. Microorganisms which grew on selective media were identified using biochemical methods. The data were statistically analyzed by Kruskal-Wallis test, followed by Dunn's post-test (alpha=0.05).


RESULTS
Microwave irradiation for 3 min (Group 1) resulted in sterilization of all dentures evaluated. After microwave irradiation for 2 min (Group 2), a significant decrease in Candida spp. (P=0.0062), Staphylococcus spp. (P=0.0178), mutans streptococci (P=0.0047) and non-identified species (P<0.0001) was achieved in comparison with the cfu/mL obtained before irradiation. The colonies grown after 2 min of microwave irradiation were identified as Candida albicans, non-aureus Staphylococci and Streptococcus mutans.


CONCLUSIONS
Microwave irradiation for 3 min may be a potential treatment to prevent cross-contamination.
Ribeiro
Daniela Garcia
DG
R. Humaitá n degrees 1680, CEP 14801-903, Department of Dental Materials and Prosthodontics, São Paulo State University, UNESP, Araraquara Dental School, Araraquara, São Paulo, Brazil.
Pavarina
Ana Cláudia
AC
Dovigo
Lívia Nordi
LN
Palomari Spolidorio
Denise Madalena
DM
Giampaolo
Eunice Teresinha
ET
Vergani
Carlos Eduardo
CE
D000368:Aged; D000369:Aged, 80 and over; D018441:Biofilms / Q000528:radiation effects; D002176:Candida albicans / Q000528:radiation effects; D015169:Colony Count, Microbial; D003827:Denture, Complete, Upper / Q000382:microbiology*; D004203:Disinfection / Q000379:methods*; D006801:Humans; D019552:Infection Control, Dental / Q000379:methods*; D008872:Microwaves; D008875:Middle Aged; D013210:Staphylococcus / Q000528:radiation effects; D013295:Streptococcus mutans / Q000528:radiation effects; D013997:Time Factors