3 research outputs found
Evaluation of an Automated Dental Unit Water System's Contamination Control Protocol
Methods: A dental unit water system simulation device equipped
with 4 dental unit water systems and with naturally grown and
mature biofilm contamination was used in this study (3 treatment
units and 1 control). One treatment group used a simulated
5 minutes contact with TAED perborate and sterile water for
irrigation; the second used a simulated 5 minutes contact with
TAED perborate and 2 ppm ClO2 for irrigation; the third used a
simulated 5 minutes contact with TAED perborate and municipal
water for irrigation; The control group used municipal water for
irrigation with no cleaning/disinfection protocols. This protocol
was repeated for 30 cycles. Laser scanning confocal microscopy
(LSCM) was used to study the effects on natural and mature
biofilms, and R2A agar used to quantify heterotrophic plate
counts in the effluent irrigant. Antimicrobial efficacy was
evaluated by challenging TAED perborate with microbes and
spores (M. smegmatis and B. subtilis). Deleterious effects of
the germicide were evaluated on metal and nonmetal parts of
dental unit water systems. Heterotrophic plate counts using R2A
agar, and LSCM of the lines were conducted to assess biofilm
and microbial control.
Results: Baseline water samples showed mean contamination
>5.6 log10 cfu/ml. After initial cleaning, all three groups
maintained mean contamination levels of less than 1.1 (SD <0.3)
log10 cfu/ml. LSCM of baseline samples was positive for live
biofilm in all groups. At the end of the study, viable biofilm was
only present in the control. In the microbial challenge test, all
vegetative organisms were killed within 30 seconds of contact,
while spores were killed within 5 minutes. Corrosion was seen
in metals used in US manufactured dental unit materials, while
none observed in those used in the Castellini Logos Jr dental
unit