Abstract
In the present study, water was circulated in a
simulated dental unit water line with electrifying a
small current. The morphology of the biofilm
developed on inner surface of the water line and
the number of heterotrophic bacteria were investigated
to elucidate the effect of a low level electric
current on the biofilms formation associated with
bacteria reproduction.
Destruction and malconformation of biofilms by
electrification was observed using SEM, in addition
to deformation and hypertrophy of the bacteria. By
naked eye observation, small pieces, which were
possibly exfoliated biofilms, were detected in
electrified water. While an adherent, yellow gel
was demonstrated on the inner surface of the
water line without electrification.
With electrification, the number of bacteria
decreased during the first week, however the bacteria
increased gradually after that. The number of
bacteria without electrification was consistently
greater than that with electrification and the difference
was statistically significant (P<0.05). The
predominant bacteria were identified as
Sphingomonas paucimobilis. The excess chlorine
levels decreased to a minimum value within one
week.
The small current appeared to have effects on
biofilm formation of heterotrophic bacteria that
resulted in enhanced chlorine sterilization of dental
unit water. Thus, electrification has considerable
potential for the extermination of bacterial
biofilms in dental unit water lines.
