Clinical evaluation of the efficacy of removing microorganisms to disinfect patient-derived dental impressions.
OBJECTIVE
Disinfection of dental impressions is an indispensable procedure for the control of cross-contamination; however, there is limited information on the efficacy of disinfection under clinical conditions. The objective of this study was to clinically evaluate the disinfection efficacy of commercially available agents in removing oral pathogens from patient-derived impressions.


METHODS
Impressions from 54 patients were divided into groups and either left undisinfected or underwent 1 of 5 disinfection treatments: (1) 2% glutaraldehyde (GA), (2) 1% sodium hypochlorite (SH), (3) 0.25% benzalkonium chloride (BC), (4) 1 ppm ozonated water (OW), or (5) the Hygojet/MD520 system (HJ). An impression culture technique using a brain heart infusion agar medium was used to visualize the microbial contamination on the surface of the impression cultures. The persistent presence of oral pathogens on the impression cultures was examined using selective isolation agar plates.


RESULTS
The isolation frequencies of streptococci, staphylococci, Candida, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa species from undisinfected impressions were 100%, 55.6%, 25.9%, 25.9% and 5.6%, respectively. Disinfection with HJ and BC removed the microorganisms with the greatest efficacy, followed by GA, SH, and OW. Potential bacterial contamination could be detected even after disinfection had been performed. Combined use of BC plus GA or SH removed oral pathogens almost completely from dental impressions.


CONCLUSIONS
This investigation showed that potential contaminants are still present, even after general disinfection procedures. Therefore, either HJ or the combined use of BC with GA or SH is recommended for clinical and laboratory use.
Egusa
Hiroshi
H
Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, Osaka, Japan. egu@dent.osaka-u.ac.jp
Watamoto
Takao
T
Matsumoto
Takuya
T
Abe
Keiko
K
Kobayashi
Munemasa
M
Akashi
Yoshihiro
Y
Yatani
Hirofumi
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001419:Bacteria / Q000302:isolation & purification; D002175:Candida / Q000302:isolation & purification; D015169:Colony Count, Microbial; D019551:Dental Disinfectants; D003761:Dental Impression Technique; D004203:Disinfection / Q000379:methods*; D005260:Female; D006801:Humans; D019552:Infection Control, Dental / Q000379:methods*; D008297:Male; D008875:Middle Aged; D003765:Models, Dental / Q000382:microbiology*; D055815:Young Adult
D019551:Dental Disinfectants