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Abstract

This short review focuses on biofilms in the dental clinic environment. Microbial biofilms are potentially a significant source of cross-contamination and cross-infection in the dental clinic. Biofilms in dental chair unit waterlines (DUWLs), suction hoses and fittings pose the most significant risk as these may come into contact with the patient during treatment. These can be managed effectively by regular disinfection using chemical disinfectants and procedures that have proven efficacy. As dental chair units (DCUs) are classified as medical devices, there is a requirement for DCU manufacturers to provide detailed guidance for their decontamination. Planned routine preventive maintenance of the dental clinic water network and good quality water will considerably minimise infection risks from microorganisms in tap water and has benefits for the operation of other clinic equipment. Regular and effective cleaning and disinfection of taps, sinks and splash-backs will help to minimise reservoirs and disseminators of potentially pathogenic bacteria from these areas.
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Journal of Infection Prevention
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DOI: 10.1177/1757177410376845
2010 11: 192 originally published online 13 August 2010Journal of Infection Prevention
David C Coleman, Mary J O'Donnell, Maria Boyle and Ronnie Russell
Microbial biofilm control within the dental clinic: reducing multiple risks
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19
2 Journal of Infection Prevention
NOVEMBER
2010 VOL. 11 NO. 6
R
© The Author(s) 2010
Reprints and permissions:
http://www.sagepub.co.uk/journalsPermissions.nav
10.1177
/
1757177
4
103768
45
Peer reviewed article
his short review focuses on biofi lms in the dental
clinic environment. Microbial biofi lms are poten-
tially a signifi cant source of cross-contamination
and cross-infection in the dental clinic. Biofi lms in dental
chair unit waterlines (DUWLs), suction hoses and fi ttings
pose the most signifi cant risk as these may come into
contact with the patient during treatment. These can be
managed effectively by regular disinfection using chemi-
cal disinfectants and procedures that have proven effi -
cacy. As dental chair units (DCUs) are classifi ed as
medical devices, there is a requirement for DCU manu-
facturers to provide detailed guidance for their decon-
tamination. Planned routine preventive maintenance of
the dental clinic water network and good quality water
will considerably minimise infection risks from microor-
ganisms in tap water and has benefi ts for the operation of
other clinic equipment. Regular and effective cleaning
and disinfection of taps, sinks and splash-backs will help
to minimise reservoirs and disseminators of potentially
pathogenic bacteria from these areas.
Intr
od
u
c
ti
o
n
Biofi lms are a
gg
re
g
ations of microor
g
anisms, mainly bacterial spe
-
cies, characteristically growing attached to each other and to a sur
f
ace.
Bi
o
fi l m
s
ca
n f
o
rm
o
n
b
i
ot
i
c
a
n
d
ab
i
ot
i
c
su
rf
aces.
Thi
s
i
s
t
h
e
n
atura
l
mo
d
e of
g
rowt
h
of microor
g
anisms, w
h
ere t
h
ey
b
ecome
a
dh
erent, attac
h
an
d
, if in an aqueous environment, secrete a vo
l
umi
-
n
ous
p
rotective matrix com
p
osed mainl
y
of com
p
lex
p
ol
y
saccharides
which may additionally incorporate inorganic substances from their
environment
(
Costerton, 2007
)
. Biofi
l
ms often
h
ar
b
our mu
l
ti
pl
e
m
icroor
g
anism types inc
l
u
d
in
g
b
acteria, fun
g
i, protozoa, amoe
b
ae
and al
g
ae. Biofi lm formation in aqueous environments in a dental
setting, such as in pipes, tubing, tanks, wash hand basins and sinks,
ften begins with the formation of a conditioning pellicle of inor-
ganic compounds from the environment. The initial colonisers adhere
t
o t
h
e surface t
h
rou
gh
wea
k
, reversi
bl
e van
d
er Waa
l
s forces an
d
s
u
b
sequent
l
y attac
h
t
h
emse
l
ves more permanent
l
y
b
y ot
h
er ce
ll
a
dh
esion met
h
o
d
s. T
h
is initia
l
l
ayer provi
d
es more
d
iverse a
dh
esion
s
ites for other microorganisms and also commences growth itself.
A
lmost immediately, protective matrix secretion is triggered. Biofi lms
are
h
i
ghl
y structure
d
communities wit
h
a sop
h
isticate
d
d
e
g
ree of
intercommunication via
b
ioc
h
emica
l
si
g
na
ll
in
g
, w
h
erein ce
ll
p
h
eno-
typ
es and function alter considerabl
y
(
Dave
y
and O’Toole, 2000 ;
Watnick and Kolter, 2000 ; Costerton, 2007
)
. Biofi lms exhibit
increase
d
resistance to
d
eter
g
ents,
d
isinfectants an
d
anti
b
iotics, as
th
e
d
ense matrix an
d
t
h
e outer
l
ayers of ce
ll
s protect t
h
e interior of
t
heir community.
Microbial contamination of an extensive range of medical devices
has been shown to be an im
p
ortant cause of cross-contamination
an
d
cross-infection, especia
ll
y in
h
ea
l
t
h
care environments ( Lemaitre
e
t a
l
, 1996 ; Weinstein, 1998 ; Ba
g
s
h
aw an
d
Laup
l
an
d
, 2006 ;
O’Donnell et al, 2006a
)
. Wet or humid
p
arts of medical devices are
favourable to the establishment and growth of microbial biofi lms
an
d
h
ave
b
een
p
articu
l
ar
ly
associate
d
wit
h
cross-infection an
d
c
ross-contamination ( Lemaitre et a
l
, 1996 ; Hsue
h
et a
l
, 1998 ; Pero
l
a
e
t al, 2002 ).
D
enta
l
c
h
a
i
r un
i
ts
T
h
e
d
enta
l
c
h
air unit (DCU) is fun
d
amenta
ll
y t
h
e most si
g
nifi cant
piece of equipment require
d
for t
h
e practice of
d
entistry. Mo
d
ern
DCUs combine all operating essentials into one compact assemblage
c
omprising an array of complex, integrated equipment systems that
provi
d
e t
h
e services (e.
g
. water, air supp
l
y, e
l
ectrica
l
power, suction
ystem) an
instruments necessary for a
roa
ran
e of
enta
proce-
dures ( Coleman et al, 2007 , 2009 ). DCUs are classifi ed as medical
devices, and as the
y
can be used in the treatment of man
y
p
atients
Microbial biofi lm control within the dental clinic:
reducing multiple risks
David C Coleman
1,
* , Mary
J
O’Donnell
1
,
Maria Bo
y
le
1
and Ronnie Russell
2
1 . Du
bl
in Denta
l
Sc
h
oo
l
an
d
Hospita
l
, Trinity Co
ll
ege Du
bl
in, Linco
l
n P
l
ace, Du
bl
in, Ire
l
an
d
Emai
l
:
d
avi
d
.co
l
eman@
d
enta
l
.tc
d
.ie
2 . Department o
f
Micro
b
io
l
o
g
y, Trinity Co
ll
e
g
e Du
bl
in, Du
bl
in, Ire
l
an
d
* Correspon
d
in
g
aut
h
o r
Acce
p
te
d
for
p
u
bl
ication: 3 June 2010
Keywor
d
s: Biofi
l
m contro
l
, contaminate
d
aeroso
l
s ,
d
enta
l
c
h
air suction system ,
d
enta
l
c
h
air unit water
l
ines ,
wash hand basin and ta
p
contamination , water network , waterline biofi lm
A
bstr
a
ct
T
VOL. 11 NO. 6 NOVEM
B
ER 2
0
10
Journal of Infection Prevention
193
Peer reviewed article
d
ai
l
y, micro
b
ia
l
contamination of specifi c constituent parts can
b
e a
signifi cant potential source of cross-infection ( Anonymous, 1993 ;
O’Donnell et al, 2005 , 2006a
)
. This is
p
articularl
y
im
p
ortant when
i
mmunocompromise
d
patients or patients wit
h
un
d
er
l
yin
g
d
iseases
are treate
d
( O’Donne
ll
et a
l
, 2006a ). DCU components t
h
at come into
direct contact with the patient's oral cavity are of particular concern,
i
ncluding DCU-supplied instruments, DCU output water, and also
t
he suction system hoses and fi ttings. In addition, aerosol formation
an
d
d
issemination is a consequence of maintenance
us
h
in
g
proce
-
d
ures an
d
treatments usin
g
compresse
d
air, suction, u
l
trasonics or
dental drills.
DUWLs an
d
associate
d
b
io
l
ms
Water is essentia
l
for t
h
e operation of a ran
g
e of DCU-supp
l
ie
d
instru
-
m
ents (e.
g
. dental handpieces (drills), ultrasonic scalers and three
-
way air/water syringes) and for cooling tooth surfaces during dental
p
rocedures
(
Coleman et al, 2009
)
. DCU-su
pp
lied water is also used b
y
patients for ora
l
rinsin
g
an
d
to was
h
out t
h
e DCU spittoon
b
ow
l
, or
cuspi
d
or, after ora
l
rinses. A networ
k
of
d
enta
l
unit water
l
ines
(
DUWLs) consisting of several metres of interconnected narrow-bore
p
lastic tubes with an internal diameter of a few millimetres su
pp
lies
water to a
ll
DCU-su
ppl
ie
d
instruments an
d
ot
h
er DCU water out
l
ets
(
Co
l
eman et a
l
, 2007 ). Numerous stu
d
ies
h
ave s
h
own t
h
at untreate
d
DUWLs harbour resident microbial biofi lms that result in the presence
of high densities of microorganisms, primarily bacterial species, in
DUWL out
p
ut water
(
reviewed b
y
Coleman et al, 2009
)
. Bacterial
d
ensities up to 10
8
co
l
ony-formin
g
units (cfu) per m
l
of output water
h
ave
b
een reporte
d
( Souza-Gu
g
e
l
min et a
l
, 2003 ; Co
l
eman et a
l
,
2009 ). This can occur despite the DCU being supplied with sterile or
n
ear-sterile water.
W
ater fl ow within DU
W
Ls is laminar and conse
-
q
uent
ly
t
h
e
ow at t
h
e
l
umen surfaces is minima
l
com
p
are
d
wit
h
t
h
at
at t
h
e centre a
ll
owin
g
b
iofi
l
m to form rea
d
i
l
y. Furt
h
ermore, water sta
g-
n
ation wit
h
in DUWLs w
h
en DCUs are not
b
ein
g
use
d
, faci
l
itates t
h
e
growth of biofi lm ( Coleman et al, 2009 ). Subsequently planktonic
forms of microorganisms and pieces of biofi lm are released to seed
b
iofi
l
m formation e
l
sew
h
ere in t
h
e water
l
ine networ
k
or are transferre
d
d
irect
l
y into t
h
e mout
h
s of patients
d
urin
g
d
enta
l
proce
d
ures. Denta
l
h
andpieces and ultrasonic scalers generate aerosols and fi ne droplets
containing planktonic microorganisms, their endotoxins and pieces of
b
iofi
l
m can
b
e in
h
a
l
e
d
into t
h
e
l
un
g
s
b
ot
h
of patients an
d
d
enta
l
h
ea
l
t
h
care staff ( Fotos et a
l
, 1985 ; Reint
h
a
l
er et a
l
, 1988 ; At
l
as et a
l
,
1
995 ; Putnins et al, 2001 ; Pankhurst et al, 2005 ; Dutil et al, 2007 ).
Conse
q
uentl
y
, DUWL biofi lm acts as a reservoir for continuous con
-
t
amination of DUWL out
p
ut water and can act as a
p
otential source
of cross-infection an
d
can a
l
so
h
ave a p
h
ysica
l
impact on
th
e contro
l
va
l
ves an
d
function of t
h
e instruments. Steri
l
isation of
t
he dental instruments attached to DUWLs has no affect at all
on biofi lm in DUWLs within the main bod
y
of the DCU
(
O’Donnell
et a
l
, 2006a
)
.
T
h
e ma
j
ority of micro
b
es foun
d
in DUWL output water are Gram
-
n
e
g
ative aerobic heterotrophic environmental bacterial species of low
pathogenic risk. Yeasts, fungi, amoebae and protozoa can also be
present. Human pathogens found in DUWLs include
L
egionell
a
s
pp
.,
Pseudomonas
spp., an
d
non-tu
b
ercu
l
osis Myco
b
acterium spp. ( Fotos
et a
l
, 1985 ; Mayo et a
l
, 1990 ; At
l
as et a
l
, 1995 ; Sc
h
u
l
ze-Rö
bb
ec
k
e
et al, 1995 ; Porteous and Coole
, 2004 ; Dutil et al, 2007
. Water
ro
vided to DCUs can be su
pp
lied either from inde
p
endent bottle-t
yp
e
r
eservoirs or a connection ori
g
inatin
g
from t
h
e municipa
l
mains supp
l
y
(
Co
l
eman et a
l
, 2007 ). Wit
h
in t
h
e European Union, t
h
e ma
j
ority of
DCUs are supplied with municipal mains water ( Walker and Marsh,
2004
)
. Water su
pp
lied to individual DCUs directl
y
from munici
p
al
water su
pp
lies usuall
y
contains low numbers of a variet
y
of bacterial
species t
h
at eventua
ll
y
g
ive rise to mu
l
tispecies
b
iofi
l
m in DUWLs
(
Pan
kh
urst et a
l
, 1998 ; Mi
ll
s, 2000 ; Tutt
l
e
b
ee et a
l
, 2002 ). Reservoir
bottles in DCUs are manuall
y
lled with water
(
munici
p
al water, dis-
t
illed water or sterile water
)
but these can easil
y
become contaminated
wit
h
s
k
in
b
acteria suc
h
as stap
h
y
l
ococci, t
h
us intro
d
ucin
g
a
dd
itiona
l
h
uman microor
g
anisms into DUWLs ( Lance
ll
otti et a
l
, 2007 ). Denta
l
instruments supplied with DUWLs that are used in the patient’s
mouth (e.g. handpieces, air/water syringes and ultrasonic scalers)
s
hould contain integrated antiretraction valves that prevent backfl ow
o
f
ui
d
s from t
h
e ora
l
cavity into t
h
e DUWLs ( Co
l
eman et a
l
, 2007 ).
However, t
h
ese frequent
l
y fai
l
, a
dd
in
g
to t
h
e ran
g
e of microor
g
anisms
present in DUWL biofi lms and increasing the potential for transmis-
s
ion of pathogenic microorganisms ( Berlutti et al, 2003 ; Coleman
e
t a
l
, 2009 ). In
d
enta
l
h
ospita
l
s an
d
c
l
inics
h
avin
g
mu
l
tip
l
e DCUs, t
h
e
water supp
l
ie
d
to DCUs frequent
l
y comes from
l
ar
g
e
h
o
ld
in
g
tan
k
s
s
upplied with mains water. This water tends to have hi
g
her densities
o
f bacteria,
p
robabl
y
due to biofi lm formation on the inner surfaces
o
f the holding tanks ( O’Donnell et al, 2009 ). The condition of the
mains water
d
istri
b
ution pipewor
k
an
d
stora
g
e tan
k
s (w
h
ere present)
p
l
us t
h
e presence of se
d
iment or corrosion
d
eposits t
h
rou
gh
out t
h
e
s
ystem also play a signifi cant role in the quality of water supplied to
DUWLs
(
Coleman et al, 2009
)
. The
q
ualit
y
of DUWL out
p
ut water
is in
uence
d
d
irect
ly
by
t
h
e
phy
sica
l
content, c
h
emica
l
content an
d
micro
b
io
l
o
g
ica
l
qua
l
ity of t
h
e inwar
d
supp
l
y water ( Co
l
eman et a
l
,
2007 , 2009). The poorer the quality of water supplied to DUWLs,
t
he more readil
y
biofi lm will form. Poor water
q
ualit
y
also has fre-
q
uentl
y
overlooked deleterious effects on other dental clinic e
q
ui
p
-
ment an
d
its functiona
l
ity, for examp
l
e autoc
l
aves, u
l
trasonic
b
at
h
s
an
d
was
h
er
d
isinfectors to
g
et
h
er wit
h
enzyme an
d
c
l
eanin
g
so
l
u-
t
i
o
n
s
used
in
t
h
e
m
.
DUWL output water can also be a signifi cant source of bacterial
e
n
d
otoxin,
(l
i
p
o
p
o
ly
sacc
h
ari
d
e
(
LPS
)
re
l
ease
d
from t
h
e ce
ll
wa
ll
s of
Gram-ne
g
ative
b
acteria). Leve
l
s up to 100,000 en
d
otoxin units (EU)
per mi
ll
i
l
itre
h
ave
b
een reporte
d
( Putnins et a
l
, 2001 ; Pan
kh
urst an
d
Coulter, 2007 ; Singh et al, 2010 ). Inhaled endotoxin can precipitate
reactive airwa
y
s
y
m
p
toms
(
Schwartz, 2001
)
and asthma severit
y
is
d
irect
l
y corre
l
ate
d
wit
h
concentration of en
d
otoxin ( Mic
h
e
l
et a
l
,
1996 ). In me
d
ica
l
d
evices t
h
at are prone to
b
iofi
l
m contamination
uch as humidifi ers, a hypersensitivity pneumonitis triggered by con-
t
aminating endotoxin is well documented ( Pankhurst and Coulter,
2007 ). Resu
l
ts from a sin
gl
e,
l
ar
g
e, practice-
b
ase
d
cross-sectiona
l
s
tu
d
y reporte
d
a tempora
l
association
b
etween occupationa
l
exposure
t
o contaminated DUWL output water havin
g
aerobic counts of
>
200
c
fu/ml at 37
°
C and development of asthma in the sub-group of den-
t
ists in whom asthma arose following the commencement of dental
t
rainin
g
( Pan
kh
urst et a
l
, 2005 ).
Few cases of cross-infection re
l
ate
d
to contaminate
d
DUWL
o
ut
p
ut water have been re
p
orted in the literature
(
Martin, 1987 ;
Atlas et al, 1995 ), however, such infections may have gone undetec-
t
e
d
an
d
unre
p
orte
d
b
ecause of t
h
e fai
l
ure to associate ex
p
osure to
DUWL output water an
d
aeroso
l
s
g
enerate
d
from t
h
is water wit
h
t
he development of specifi c infections or symptoms ( Pankhurst and
Coulter, 2007 ). Sporadic infections not requiring hospitalisation are
also less likely to be investigated. Studies have shown that occupa-
t
iona
l
exposure to aeroso
l
s of water
b
orne
b
acteria
g
enerate
d
b
y
d
enta
l
instruments attac
h
e
d
to DUWLs may cause a
h
i
gh
er preva-
l
ence of antibodies to Legionella
(
Fotos et al, 1985 ; Borella et al,
2008
)
.
The presence of large numbers of microorganisms in DUWL
o
ut
p
ut water con
icts wit
h
infection contro
l
an
d
p
revention
b
est
pract
i
ce.
Control and elimination o
f
DUWL bio
lm
There is currentl
y
no Euro
p
ean Standard for the
q
ualit
y
of DUWL
o
utput water. T
h
e American Denta
l
Association (ADA) Counci
l
on
1
9
4
Journal of Infection Prevention
NOVEMBER
2010 VOL. 11 NO.
R
6
Peer reviewed article
S
cientifi c Affairs set a
g
oa
l
for t
h
e year 2000 t
h
at water use
d
for
d
enta
l
t
reatment should contain
200 cfu/ml of aerobic heterotro
p
hic bacte
-
r
ia
(
Anon
y
mous, 1996
)
. Man
y
ex
p
erts in the fi eld have endorsed this
r
ecommen
d
ation
(
Co
l
eman an
d
O’Donne
ll
, 2007
)
. Over t
h
e
l
ast two
d
eca
d
es, many approac
h
es
h
ave
b
een propose
d
for re
d
ucin
g
t
h
e
m
icrobial density in DUWL output water, the most effi cient of which
i
s regular treatment/disinfection of DUWLs with a biocide or cleaning
agent that removes biofi lm from DUWLs effectively, resulting in good
qua
l
ity output water ( Tutt
l
e
b
ee et a
l
, 2002 ; Co
l
eman et a
l
, 2007 ,
2009; see a
l
so Ta
bl
e 1 in t
h
e review
b
y Wa
lk
er an
d
Mars
h
, 2007 for a
l
ist of DUWL treatment agents). Biofi lm re-growth in DUWLs seeded
from su
pp
l
y
water and/or dental instruments connected to DUWLs
u
se
d
in t
h
e ora
l
cavity occurs s
h
ort
l
y fo
ll
owin
g
d
isinfection
/
c
l
eanin
g
an
d
so DUWLs nee
d
b
e treate
d
repeate
dl
y (e.
g
. once wee
kl
y) or con
-
t
inuously with a residual treatment a
g
ent ( Coleman et al, 2009 ). Many
studies have demonstrated the effi cacy of a broad range of commer
ciall
y
available treatment
p
roducts for DUWLs that effi cientl
y
remove
b
iofi
l
m an
d
re
d
uce
b
acteria
l
d
ensity in DUWL output water to pota
bl
e
water qua
l
ity or
b
etter (see t
h
e review
b
y Co
l
eman et a
l
, 2009 ). How
-
ever, man
y
of these studies were conducted
i
n v
i
tr
o
and relativel
y
few
actually investigated the effi cacy of DUWL treatment products to
ac
h
ieve t
h
ese
d
esire
d
effects in DCUs in
l
on
g
-term stu
d
ies. Some
DUWL treatment a
g
ents
h
ave
b
een reporte
d
to ex
h
i
b
it a
d
verse affects
on DCU components or on dental restorative materials, while others
h
ave been re
p
orted to mobilise the release of toxic substances to the
environment in wastewater
(
Coleman et al, 2009
)
. It is im
p
ortant that
d
enta
l
c
l
inicians an
d
practice mana
g
ers are provi
d
e
d
wit
h
specifi c
DUWL
d
isinfection protoco
l
s an
d
approve
d
treatment a
g
ents
b
y t
h
e
DCU manufacturers for each individual DCU model
(
Table 1
)
. There
i
s a re
q
uirement for DCU manufacturers to
p
rovide such information
as DCUs are c
l
assifi e
d
as me
d
ica
l
d
evices un
d
er t
h
e Euro
p
ean Me
d
ica
l
Devices Directive ( Anonymous, 1993 ).
T
h
e recent
d
eve
l
opment of nove
l
DCUs containin
g
inte
g
rate
d
, semi
-
automated or automated DUWL cleaning systems for use with treat
-
m
ent agents that have been shown to be effective in controlling
DUWL
b
iofi
l
m effective
l
y in
l
on
g
-term stu
d
ies
h
ave si
g
nifi cant
l
y sim
-
p
l
ifi e
d
t
h
e mana
g
ement of DCU output water qua
l
ity ( O’Donne
ll
et a
l
,
2006b , 2007
)
. More recentl
y
, the develo
p
ment and im
p
lementation in
a dental teaching hospital of a large-scale system capable of auto
-
m
atica
ll
y an
d
consistent
l
y maintainin
g
t
h
e micro
b
io
l
o
g
ica
l
an
d
c
h
em
-
i
ca
l
qua
l
ity of DCU supp
l
y an
d
output water at
b
etter t
h
an pota
bl
e
quality simultaneously in multiple DCUs (
<
100 cfu/ml) has proven to
be a robust solution to the problem of DUWL biofi lm and with sig
-
n
ifi cant economic benefi ts in reduced e
q
ui
p
ment maintenance, mate
-
r
ia
l
s an
d
l
a
b
our ( O’Donne
ll
et a
l
, 2009 ).
DCU suction s
y
stem bio
lm
Modern DCUs are e
q
ui
pp
ed with a suction s
y
stem to remove fl uids
an
d
d
e
b
ris from t
h
e ora
l
cavity
d
urin
g
d
enta
l
proce
d
ures an
d
to mini
-
m
ise aeroso
l
re
l
ease into t
h
e
d
enta
l
c
l
inic environment
d
urin
g
t
h
e use
of dental instruments attached to DUWLs, especially hi
h-speed cut
t
ing instruments (i.e. handpieces fi tted with burrs) ( O’Donnell et al,
2005 ). During use, both tooth and burr are constantly sprayed with
coo
l
water, w
h
ic
h
g
enerates a fi ne aeroso
l
t
h
at contains t
h
e patient's
sa
iva, ora
an
DUWL water-
erive
microor
anisms an
toot
par
t
icles. These microorganisms may include pathogenic bacteria, viruses
and fungi and can result in signifi cant contamination of the dental
c
l
inic environment
(
Rautemaa et a
l
, 2006
)
. Use of t
h
e suction s
y
stem
si
g
nifi cant
l
y re
d
uces t
h
e
l
eve
l
s of aeroso
l
s, spray an
d
sp
l
atter re
l
ease
d
i
nto the dental clinic environment.
Many modern DCUs have two types of suction termed high-volume
suction and low-volume suction, both su
pp
lied b
y
a common vacuum
source ( O’Donne
ll
et a
l
, 2005 ). T
h
e
h
i
gh
-vo
l
ume suction
h
ose is use
d
t
o re
d
uce aeroso
l
s an
d
spray an
d
to remove
d
e
b
ris an
d
DUWL water,
whereas the low-volume suction hose, or saliva ejector, is used mainly
t
o remove excess fl uids from the
p
atient’s mouth. Prior to commence-
ment of eac
h
d
enta
l
p
roce
d
ure, a reusa
bl
e steri
l
e wi
d
e
b
ore suction ti
p
is connecte
d
to t
h
e en
d
of t
h
e
h
i
gh
-vo
l
ume suction
h
ose an
d
a sin
gl
e-
patient-use disposable saliva ejector tip is attached to the narrower
bore saliva ejector hose. When the suction system is activated and the
high-volume suction tip or saliva ejector is in position in the patients
mout
h
, water,
bl
oo
d
, aeroso
l
s an
d
d
e
b
ris are aspirate
d
from t
h
e
patient’s mout
h
t
h
rou
gh
t
h
e suction
h
oses. Bot
h
t
h
e
h
i
gh
- an
d
l
ow-
volume suction hoses are connected to a common suction
p
i
p
e within
t
he main body of the DCU through which waste fl uids eventually pass
t
o a centra
l
separation vesse
l
,
h
avin
g
rst passe
d
t
h
rou
gh
an ama
lg
am
t
rap to remove pieces of
d
enta
l
ama
lg
am an
d
a coarse fi
l
ter to remove
particulate matter. Furthermore, waste fl uids from the DCU spittoon
pass through the common suction pipework within the DCU. All of
t
hese com
p
onents form
p
art of the DCU suction s
y
stem and become
c
ontaminate
d
wit
h
ora
l
an
d
DUWL-
d
erive
d
microor
g
anisms. As t
h
e
uction system components are frequent
y wet, t
ey provi
e an envi-
ronment that is conducive to the growth and proliferation of biofi lm
(
O’Donnell et al, 2005
)
. It is not
p
ractical to remove and either ther-
ma
lly
d
isinfect or steri
l
ise t
h
e suction
h
oses eit
h
er after eac
h
p
atient or
o
n a
d
ai
l
y
b
asis. For t
h
ese reasons DCU suction systems s
h
ou
ld
b
e
disinfected re
g
ularly. However, in individual dental sur
g
eries the fre-
q
uenc
y
of suction s
y
stem disinfection can var
y
widel
y
(
Watson and
Whitehouse, 1993
)
. The usual method of DCU suction s
y
stem disin-
fection is to aspirate
d
isinfectant t
h
rou
gh
t
h
e suction
h
oses. Best
practice a
d
vocates t
h
at t
h
is s
h
ou
ld
b
e un
d
erta
k
en twice
d
ai
l
y after t
h
e
morning and afternoon treatment sessions. Because all DCU suction
s
ystems operate in a manner analogous to a domestic vacuum cleaner,
d
isinfectant is suc
k
e
d
rapi
dl
y t
h
rou
gh
t
h
e suction
h
oses an
d
ot
h
er
s
uction system components resu
l
tin
g
in very s
h
ort contact times
(
O’Donne
ll
et a
l
, 2005 ). Stu
d
ies from t
h
is
l
a
b
oratory
h
ave s
h
own t
h
at
DCU suction hoses and suction s
y
stem com
p
onent
p
arts harbour
e
xtensive biofi lm
p
o
p
ulated mainl
y
b
y
P
seudomonas
s
pp
. and that
uction systems can remain extensive
y contaminate
wit
via
e
io-
l
m
d
espite re
g
u
l
ar
d
isinfection ( O’Donne
ll
et a
l
, 2005 ). A sma
ll
number of studies have shown that, under certain conditions, fl uids
fr
o
m
t
h
e
l
ow
-v
o
l
u
m
e
suct
i
o
n h
oses
ca
n
be
r
et
r
acted
back
in
to
a
patient’s mout
h
d
urin
g
use ( Watson an
d
W
h
ite
h
ouse, 1993 ; Mann
e
t a
l
, 1996 ; Bar
b
eau et a
l
, 1998 ). T
h
is p
h
enomenon cou
ld
potentia
ll
y
be an important source of cross-contamination and cross-infection in
t
he dental clinic. However, there are ver
y
few
p
ublished studies on the
ffi cac
of DCU suction s
stem disinfectants available in the litera-
t
ure. T
h
is potentia
ll
y potent source of cross-infection in t
h
e
d
enta
l
cl
inic nee
d
s to
b
e investi
g
ate
d
furt
h
er ( O’Donne
ll
et a
l
, 2005 ).
High- and low-volume suction hoses usually are equipped with spe-
ial connectors into which sterile suction tips (high-volume) or single-
patient-use sa
l
iva e
j
ector tips (
l
ow-vo
l
ume) are fi tte
d
prior to eac
h
patient treatment. T
h
ese connectors may contain intricate va
l
ve com-
ponents to re
g
ulate suction stren
g
th and may also have metal or plastic
ada
p
tors to connect them to the suction hoses. Suction hose connec-
t
ors fre
q
uentl
y
harbour resident biofi lms that are shielded from disin-
fectant
d
urin
g
routine suction system
d
isinfection an
d
t
h
ese constitute
anot
h
er potentia
l
source of cross-infection an
d
cross-contamination in
t
he dental clinic environment
(
O’Donnell et al, 2005
)
. An exam
p
le of a
biofi lm-contaminated suction connector is shown in Figure 1
.
Denta
l
c
l
inicians an
d
practice mana
g
ers s
h
ou
ld
see
k
t
h
e a
d
vice of
DCU manufacturers of in
d
ivi
d
ua
l
DCU mo
d
e
l
s for a
d
vice on specifi c
s
uction system disinfection protocols and approved disinfectants
(
Table 1 ). There is also a need for DCU designers to be more aware of
design aspects that reduce the opportunity for biofi lm formation and
faci
l
itate effective
d
econtamination ( Co
l
eman et a
l
, 2007 ).
VOL. 11 NO. 6 NOVEM
B
ER 2
0
10
Journal of Infection Prevention
1
9
5
Peer reviewed article
Table 1. Summary of practical measures for minimising infection risks from biofi lms in the dental clinic
Bi
o
lm
co
n
t
r
ol
P
ractical approach to controllin
g
biofi lms
Co
mm
e
n
ts
D
enta
l
unit
wate
rlin
es
(
DUWLs
)
C
l
ean an
d
d
isinfect DUWLs re
g
u
l
ar
l
y wit
h
treatment
agents that effectively remove biofi lm and that do
not
e
xhi
b
i
t
ad
v
e
r
se
a
ff
ects
o
n
de
n
ta
l
c
h
a
ir
u
ni
ts
(
DCUs) an
d
attac
h
e
d
d
enta
l
instruments an
d
p
referabl
y
which do not leave residues in DUWLs.
Residual DUWL treatment agents should not have
any toxic affects as t
h
ese come into
d
irect contact
with the
p
atient’s oral cavit
y
S
ee
k
a
d
vice from DCU manufacturer re
g
ar
d
in
g
suitable types of DUWL treatment agent to use in
s
p
ecifi c DCU models and also the duration and
f
requency o
f
treatment
The effi cac
y
of DUWL treatment should be
monitore
d
perio
d
ica
ll
y
b
y
d
eterminin
g
t
h
e
micro
b
io
l
o
g
ica
l
qua
l
ity of output water
S
eek advice from water hygiene professional
Inde
p
endent reservoir bottles used to su
pp
l
y
wate
r
t
o DUWLs should be cleaned regularly, disinfected
an
d
steri
l
ize
d
b
y autoc
l
avin
g
. Reservoir
b
ott
l
es
should be able to withstand repeated autoclavin
g
Se
v
e
r
a
l r
ese
rv
o
ir
bott
l
es
s
h
ou
l
d
be
a
v
a
il
ab
l
e
to
allow adequate time for reprocessing
Water used in reservoir bottles should at least be o
f
pota
bl
e qua
l
ity. Aseptic tec
h
nique s
h
ou
ld
b
e use
d
when fi lling reservoir bottles with water to minimise
potential contamination with skin microorganisms
Wear protective clothing and gloves to minimise
contamination of reservoir
b
ott
l
es an
d
water.
E
q
ui
p
ment used to
p
roduce distilled or deionized
water should be well maintained to ensure good
qua
l
ity output water. Ensure t
h
at water store
d
for
r
eservoirs does not deteriorate in
q
ualit
y
Water su
pp
lied to DUWLs should be at least o
f
pota
bl
e qua
l
ity. If it is not, pre-treat supp
l
y water to
r
emove suspen
d
e
d
or
g
anic an
d
inor
g
anic materia
l
,
dissolved hard water minerals, dissolved organic
materia
l
an
d
meta
l
s
S
eek advice from DCU manufacturer and/or water
h
y
g
iene professiona
l
U
se DCUs t
h
at are equippe
d
wit
h
inte
g
rate
d
an
d
automated or semi-automated DUWL cleaning
sys
t
em
s
T
h
ese systems simp
l
ify an
d
stan
d
ar
d
ise
b
iofi
l
m
control in DU
W
Ls. Seek advice from DCU
m
anufacturer, preferably prior to procurement
DCUs s
h
ou
ld
b
e service
d
at
l
east annua
ll
y
b
y
competent personne
l
, inc
l
u
d
ing effi cacy testing o
f
antiretraction valves/device
s
S
ee
k
a
d
vice from DCU manufacture
r
Ensure t
h
at t
h
e DUWLs in DCUs are separate
d
b
y an
air
g
ap from municipa
l
mains water supp
l
ie
s
To prevent contamination of mains water supp
l
ies
wit
h
microor
g
anisms from DUWL
b
iofi
l
m an
d/
or
water. Seek advice from DC
U
manufacturer
A
ll staff involved in DUWL decontamination should
b
e compre
h
ensive
l
y traine
d
Detailed protocols for DUWL decontamination
s
h
ou
ld
b
e provi
d
e
d
b
y DCU manufacturers
Suction s
y
stem Disinfect
h
i
gh
- an
d
l
ow-vo
l
ume suction
h
oses twice
daily after the morning and afternoon treatment
sessions usin
g
an approve
d
d
isinfectan
t
S
ee
k
a
d
vice from DC
U
manufacturer on suita
bl
e
t
ypes o
f
suction system treatment agent to use in
specifi c DCU mo
d
e
l
s
Detac
h
an
d
d
ismant
l
e suction
h
ose connectors
u
sed to attach suction ti
p
s. Clean and disinfect
th
ese
d
ai
ly
S
ee
k
a
d
vice from DCU manufacturer. If possi
bl
e
a
v
o
i
d
t
h
e
use
o
f
suct
i
o
n
co
nn
ecto
r
s
w
i
t
h in
t
ri
cate
va
l
ve components as t
h
ese encoura
g
e t
h
e
g
rowt
h
of
b
iofi
l
m an
d
t
h
e parts can easi
l
y
b
e
l
ost
d
urin
g
cleaning and disinfection
DCU suction systems should be serviced at least
annua
ll
y
b
y competent personne
l
Replace suction hoses annually
W
ater network Institute a preventive maintenance pro
g
ram on water
d
i
st
ri
but
i
o
n n
etwo
r
k
Re
p
lace heavil
y
corroded tanks, ta
p
s and
p
i
p
es.
S
eek the advice of a water hygiene professional
Re
g
u
l
ar
l
y c
l
ean an
d
d
isinfect was
h
h
an
d
b
asin
sp
l
as
h
-
b
ac
ks
U
se stain
l
ess stee
l
sp
l
as
h
-
b
ac
k
s or equiva
l
ent
n
on-porous materia
l
t
h
at can wit
h
stan
d
repeate
d
d
i
s
inf
ect
i
o
n
(Continue
d
)
196
Journal of Infection Prevention
NOVEMBER
2010 VOL. 11 NO.
R
6
Peer reviewed article
Dental clinic water s
y
stems
Water su
pp
lied to domestic wash hand basins, baths and showers is
u
sua
ll
y provi
d
e
d
from water stora
g
e tan
k
s supp
l
ie
d
wit
h
municipa
l
m
ains water. Simi
l
ar
l
y in many
d
enta
l
c
l
inics water provi
d
e
d
to was
h
h
and basins and sinks comes from water stora
g
e tanks. Such water
t
anks fre
q
uentl
y
contain sediment, the
q
uantit
y
of which ma
y
var
y
depending on the geographic location, the age of the water distribu
-
t
ion system in t
h
e faci
l
ity concerne
d
an
d
h
ow frequent
l
y an
d
we
ll
it is
m
aintaine
d
. T
h
e a
b
i
l
ity of microor
g
anisms to survive in water tan
k
s is
well documented and numerous studies have shown that water is a
signifi cant source of nosocomial infection ( Anaissie; et al, 2002 ).
Water
b
orne pat
h
o
g
ens foun
d
in water
d
istri
b
ution networ
k
s in
h
ea
l
t
h
care faci
l
ities inc
l
u
d
e Le
g
ione
ll
a spp.,
P
seu
d
omonas aeru
g
inosa
and other Pseudomonas
spp
., Stenotrophomonas maltophil
a
,
m
y
co-
bacteria, aspergilli and other moulds and fungi, amongst others
(
Anaissie et al, 2002 ; Vaerewi
j
ck et al, 2005 ; Casini et al, 2008 ; Kerr
an
d
Sne
ll
in
g
, 2009 ; Mena an
d
Ger
b
a, 2009 ). Water qua
l
ity in tan
k
s
can
d
iminis
h
for a variety of reasons inc
l
u
d
in
g
t
h
e accumu
l
ation of
m
icrobial biofi lm and the
p
resence of sediment. These can neutralise
an
y
residual free available chlorine
p
resent in the su
pp
l
y
water, facili
-
t
ate
d
ama
g
e or corrosion of tan
k
surfaces an
d
d
istri
b
ution pipewor
k
an
d
l
ea
d
to water sta
g
nation ( Co
l
eman et a
l
, 2009 ). T
h
us, t
h
e micro
-
biolo
g
ical quality of water from tank-supplied outlets in dental clinics
such as wash hand basins and sinks can be ver
y
p
oor and constitutes
a potentially signifi cant source of cross-contamination and cross
-
i
nfection in t
h
e
d
enta
l
c
l
inic. Fi
g
ure 2 s
h
ows examp
l
es of si
g
nifi cant
g
rowt
h
of pre
d
ominant
l
y Pseu
d
omonas
b
acteria (
>
10
4
cfu
/
m
l
) an
d
fun
g
i recovered from a mixer tap outlet servicin
g
a wash hand basin in
a large dental clinic in 2009. Similar microorganisms were recovered
from both water and sediment in the water tank supplying the tap.
T
aps supp
l
ie
d
b
y tan
k
water are frequent
l
y contaminate
d
wit
h
b
iofi
l
ms
Figure 1. View of a low-volume suction hose connector used to attach single-patient-use
s
aliva ejector tips. The orange O-ring on the left of the figure is used to secure the
connector in the low-volume suction hose. Extensive biofilm populated mainly by
Pseudomonas aeruginosa is evident as staining adjacent to the O-ring. The suction
s
trength regulator valve present in the centre part of the figure also harbours biofilm
evident as staining.
Figure 2. (a) Extensive growth (
>
(
(
10
4
cfu/ml) of
P
seudomonas s
pp
. recovered on
P
seudomonas agar (Lab M, Bury, Lancashire, UK) in 2009 from a wash hand basin mixer-
tap outlet supplied with tank water in a dental clinic. (b) Growth of mixed fungal species
recovered on R2A agar (Lab M) from the same water sample tested in panel (a).
Table 1. Continued
Biofi
l
m contro
l
Practica
l
approac
h
to contro
ll
ing
b
iofi
l
m
s
C
omments
O
nl
y
use wash hand basins that com
p
l
y
with Health
T
ec
h
nica
l
Memoran
d
um 64 ( Department of Hea
l
t
h
,
2
006
)
T
hese minimise the generation of contaminated
a
eroso
l
s w
h
en taps are
b
ein
g
operate
d
. Sources o
f
c
ontamination include ta
p
water, biofi lms in ta
p
s,
a
nd plugholes and wastewater below the
pl
u
gh
o
l
e out
l
et
E
nsure t
h
at t
h
ere is a
d
equate resi
d
ua
l
d
isinfection o
f
wate
r
w
i
t
hin
t
h
e
n
etwo
r
k
Th
is is important w
h
ere t
h
ere is
l
en
g
t
h
y o
r
c
omplex pipework, storage tanks or raised
t
empera
t
ures
VOL. 11 NO. 6 NOVEM
B
ER 2
0
10
Journal of Infection Prevention
19
7
Peer reviewed article
containin
g
opportunistic pat
h
o
g
ens, especia
ll
y
P
. aeru
g
inosa , an
d
n
umerous cases of cross-infection from contaminated ta
p
s in hos
p
ital
settings have been reported ( Anaissie et al, 2002 ). Furthermore, bio
l
ms in sin
k
s an
d
was
h
h
an
d
b
asins an
d
associate
d
s
pl
as
h
-
b
ac
k
s can
act as reservoirs an
d
d
isseminators of infection
d
ue to
P
seu
d
omona
s
species, particularly
P
. aeru
g
inos
a
.
C
ont
r
ol
measu
r
es
Routine preventive maintenance on t
h
e water
d
istri
b
ution system in
d
enta
l
c
l
inics is important in minimisin
g
d
eterioration of water qua
l
ity.
Heavil
y
corroded tanks, ta
p
s and
p
i
p
ework should be re
p
laced and a
preventive maintenance program should be put in place to maintain,
c
l
ean an
d
d
isinfect contaminate
d
water s
y
stems. Was
h
h
an
d
b
asin
sp
l
as
h
-
b
ac
k
s s
h
ou
ld
b
e constructe
d
of non-porous materia
l
(e.
g
.
stainless steel) and easily cleaned and disinfected. Avoidance of
splashing during tap operation is essential. Tank-supplied water is
generally not of potable quality and should not be used to fi ll DCU
r
eservoir
b
ott
l
es ( O’Donne
ll
et a
l
, 2009 ). Pota
bl
e water, steri
l
e water
or
d
isti
ll
e
d
water can
b
e use
d
for t
h
is purpose. If tan
k
-supp
l
ie
d
water
i
s used to su
pp
l
y
DCUs in dental hos
p
itals and dental clinics e
q
ui
pp
ed
with large numbers of DCUs, the water should be pre-treated to
ensure t
h
e c
h
emica
l
an
d
micro
b
io
l
o
g
ica
l
qua
l
ity of t
h
e water is of at
l
east pota
bl
e qua
l
ity or
b
etter an
d
t
h
at t
h
e DCUs are su
b
ject to re
g
u
l
ar
DUWL disinfection usin
g
an approved procedure ( O’Donnell et al,
2009 ). Hand washing sinks in dental clinics should comply with
Health Technical Memorandum 64
(
De
p
artment of Health, 2006
)
and
s
h
ou
ld
not
h
ave p
l
u
g
s or an over
ow out
l
et an
d
t
h
e tap water stream
m
ust not
ow
d
irect
l
y into t
h
e wastewater out
l
et (i.e. p
l
u
gh
o
l
e). T
h
e
m
aximum fl ow pressure to the taps should be adjusted so as not to
ause sp
as
in
. T
is re
uces t
e
eneration of contaminate
aero-
s
ols from contaminated water and ta
p
s but also from biofi lms located
in or below the plughole. Taps should preferably be elbow or wrist
op
erate
d
to re
d
uce t
h
e ris
k
of
h
an
d
contamination. Non-antise
p
tic
s
oap
b
ars or
l
iqui
d
soap s
h
ou
ld
not
b
e use
d
in t
h
e
d
enta
l
c
l
inic as
t
hese can readily become contaminated with bacteria from contami-
nated sinks and/or water and can therefore act as reservoirs and dis-
s
eminators of infection ( Hegde et al, 2006 ; Racier et al, 2008 ). Only
antiseptic soap wit
h
proven antimicro
b
ia
l
effi cacy,
gl
ove compati
b
i
l
ity
an
d
causin
g
minima
l
s
k
in irritation s
h
ou
ld
b
e use
d
. If
l
iqui
d
soap is
u
sed in the dental clinic, it should be provided in disposable cartridges
as refi llable soap containers can become contaminated during the
refi
ll
in
g
process.
C
onclusions
Microbial biofi lms are potentially a signifi cant source of cross-contam-
in
at
i
o
n
a
n
d
c
r
oss
-inf
ect
i
o
n in
t
h
e
de
n
ta
l
c
lini
c
e
nvir
o
nm
e
n
t.
Th
ese
c
an
b
e mana
g
e
d
effective
l
y
b
y imp
l
ementin
g
a
d
equate contro
l
an
d
ris
k
minimisation approac
h
es invo
l
vin
g
effective c
l
eanin
g
an
d
d
isin-
fection and preventive maintenance strategies in the key areas associ-
ated
w
i
t
h
b
i
o
lm
co
n
ta
min
at
i
o
n
.
Fundin
g
Research undertaken in the authors’ laboratory is supported by the
Microbiology Research Unit, Dublin Dental School & Hospital and by
Enterprise Ireland grant IP/2008/0589.
C
onfl ict of interest statement
N
o
n
e
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l
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e
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... (No tuberculosis). Sin embargo, la mayoría de estos organismos tienen un potencial patogénico mínimo en huéspedes inmunocompetentes (6,7). ...
... Pseudomonas aeruginosa, un bacilo Gram negativo, a pesar de ser una bacteria que no puede unirse a una superficie en caso de existir calcio y sodio; al salir de los ductos de agua, por ejemplo las piezas de mano y jeringas triples generan aerosoles y gotas de agua, que se ha demostrado, causa infección oral en pacientes (6,7). ...
Article
Full-text available
Objetivo. Recuperar y analizar la presencia de bacterias formadoras de biopelículas en las mangueras de la jeringa triple y de la pieza de mano que distribuyen el agua a las unidades dentales de la Fundación Universitaria San Martin. Método. Se realizó un estudio descriptivo de corte transversal con muestreo probabilístico. Se estudiaron las bacterias presentes en el agua recolectada en la jeringa triple y la pieza de mano, las cuales fueron seleccionadas al ser los instrumentos por los cuales transita el agua que entrará en contacto con el paciente. Se tomaron muestras antes y después de la consulta, de la jeringa triple con solo agua, con agua–aire y la pieza de mano. Se realizaron cultivos por filtración por membrana en medios Endo, Cetrimide y Sangre Azida. Resultados. Se encontraron 84 % de muestras positivas para cocos Gram positivos, mientras que el 8 % de las muestras presentaban aislamientos de bacilos Gram negativos, representado en E coli y P aeruginosa. La flora Gram positiva estuvo representada por Staphylococcus hominis y Staphylococcus epidermidis.
... Nonclinical surfaces are surfaces that are typically not exposed to contaminated gloves or equipment [12][13][14]. Research has shown that dental laboratories can also be the source of contamination [15]. Infection transmission can also occur during the transfer of dental molds and other equipment from the clinic to the laboratory. ...
Article
Full-text available
Objective: To determine the level of clinical contamination in the clinic and laboratory of the prosthodontics department of Kerman Dental School. Material and Methods: Clinical surfaces of the dental units, the laboratory, and the professors' lounge of the prosthodontics department were randomly sampled. The sampled surfaces included the dental units' console, light switch, light handle, headrest, and air-water spray syringe in the clinic, plastering tables, buttons of the vibrator, polishing, and trimmer machines, acryl tables, handles of pressure pot and press machine, handpiece holders, work desks, and drawer handles in the laboratory, and desks, computer mouse and keyboard, telephone sets, and doorknob in the professor's lounge. The samples were examined for the type and growth of microorganisms. The data were entered into SPSS, where they were analyzed using the chi-square test at the 0.05 significance level. Results: Of all the samples taken, 89.9% showed microbial contamination. The most common type of contamination was fungus (34.8%) and the least common types were Enterococcus faecalis and Staphylococcus epidermidis (1.1%). The second and third most common types of bacteria in the samples were Staphylococcus aureus (18%) and Pseudomonas aeruginosa (12.4%), respectively. There was no significant difference between the frequencies of microbial contamination in the clinic, the laboratory, and the professors' lounge. Conclusion: Given the strong chance of cross-infection in the examined department and laboratory, it is necessary to enforce protocols for proper disinfection of surfaces before, between and after treatments.
... In justifying these results, it can be stated that aerosols with a diameter of less than 50 microns can remain in the suspended space for a long time (Rautemaa, Nordberg, Wuolijoki-Saaristo, & Meurman, 2006;Coleman, O'Donnell, Boyle, & Russell, 2010) and after that the disinfection process perfumed at the end of the day, they sat during fourteen to fifteen hours on different parts of the unit, including the unit glasses spittoon and caused infection and positive microbial culture. Accordingly, it is recommended that the unit disinfection process to be performed before working on each patient in order to provide more safety, especially for people who have a weakened immune system. ...
Article
Full-text available
Introduction: Performing dental practices in the oral environment leads to the transmission of microorganisms in saliva and blood to working surfaces and dental devices and their infection. Preventing transmission of infection through these devices is an important task of a dentist. Hence, this research was conducted to evaluate the disinfection quality of the dental faculty units of Ahvaz Jundishapur University of Medical Sciences (AJUMS) in Iran.Materials and Methods: In order to evaluate the quality of disinfection of the units, sampling was performed from all glasses spittoon surfaces of 90 units of the clinical unit of the AJUMS dental faculty before and after disinfection by personnel. Then, the bacteria were cultured in a medium and examined.Results: The mean (and standard deviation) of the total infection of units of the dental faculty was 46534.4 (583380.4) colonies per 1 ml before disinfection and 40265.6 (52131.1) colonies per 1 ml after disinfection, reflecting significant decrease in number of bacterial colonies after disinfection (P <0.001). In addition, a significant decrease was seen in the number of bacterial colonies in the restoration, pediatric, orthodontic and diagnosis units (p <0.05), but the difference before and after disinfection was not significant in the prosthetic, endodontic, surgical and periodontal units. In addition, the most common types of microorganisms in the whole units of the dental faculty were pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus, respectively, and after disinfection, the most common types of microorganisms were Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus, respectively.Conclusion: In general, this study showed that the disinfection method of units in dental faculty can not reduce the severity of infection of the units. Given what was stated, it is recommended that the method and the substances used to disinfect the unit to be changed.
... The results of this study confirm earlier work done by researchers [13][14][15][16][17][18][23][24][25][26][27][28][29] demonstrating that the microbiological quality of water emerging from DUWLs does not conform to accepted guidelines for potable water. Thus, the null hypotheses were rejected. ...
Article
Background and aim: Biofilms in dental unit waterlines (DUWLs), suction hoses, and fittings are a potentially significant source of cross-contamination posing significant health risk as these may come into contact with patients during treatment. The purpose of this in vitro study was to identify the spectrum of bacterial flora colonizing the DUWLs and to detect pathogenic microorganisms present in such an environmental niche. Materials and methods: Thirty DUWL samples were collected from in use dental units selected randomly from various clinical departments. Samples were collected from the following devices; 3-in-1 syringe waterline, section of waterline tubing supplying the 3-in-1 syringe, and the air rotor water. The samples were subjected to bacteriological analysis, and all bacterial isolates were tested for their ability to form biofilms. Results: A descriptive analysis of the results obtained was carried out, and it was observed that 7 out of 30 (23.3%) samples collected from DUWL were supplying water of unsatisfactory quality with species of low-pathogenicity bacteria isolated present in significant numbers; four of ten (40%) water supply lines contained bacterial biofilms; and the species with greatest capability to form biofilms were Enterobacter species (spp.). In addition, the results were also subjected to Chi-square test which revealed no statistical difference between the species and the location of collection of samples. Conclusion: Within the limitations of this study, it is concluded that DUWLs are not totally free of contamination. Microbial biofilms are a significant source of cross-contamination and cross-infection in the dental clinic environment.
... Most bacteria tend to attach tenaciously to any available surface and readily form biofilm, which may be problematic in dental settings [4,5]. A biofilm can be defined simply and broadly as com-munities of microorganisms that are attached to a surface, and they provide a protective degree of homeostasis and stability in a changing environment [6,7]. ...
Article
Full-text available
The ability of Staphylococcus aureus to form biofilm is considered to be a major virulence factor influencing its survival and persistence in both the environment and the host. Biofilm formation in S. aureus is most frequently associated with production of polysaccharide intercellular adhesion by ica operon-encoded enzymes. The present work aimed at evaluating the in vitro biofilm production and presence of the icaA and icaD genes in S. aureus isolates from a dental clinic in Konya, Turkey. The surfaces of inanimate objects were sampled over a period of six months. S. aureus isolates were subjected to Congo Red Agar (CRA) and crystal violet (CV) staining assays to evaluate their ability of biofilm production, while the presence of the icaA and icaD genes was determined by polymerase chain reaction. S. aureus contamination was detected in 13.2% of the environmental samples. All the 32 isolates were observed to be positive for both the icaA and icaD genes. Phenotypic evaluations revealed that CV staining assay is a more reliable alternative to CRA assay to determine biofilm formation ability. A high percentage of agreement (91%) was observed between the results from CV staining and ica genes’ detection assays. Phenotypic and genotypic evaluations should be combined to detect biofilm formation in S. aureus. Our findings indicate that dental clinic environments should be considered as potential reservoir for biofilm-producing S. aureus and thus cross contamination.
... 11 The aerosols that form in the dental clinics from both the equipment and patient sources can cause droplet infections such as tuberculosis, influenza, Legionnaires' disease, sudden acute respiratory syndrome (SARS), pneumonic plague, etc. 12 Certain dental professionals such as the pediatric and orthodontic dental teams are more prone to infections like mumps, measles, chicken pox, cytomegalovirus, etc. 13 Babaji et al (2011) reported that during the working hours in a clinic, air bacterial count has a 3-fold increase (aerobic bacterial count increasing 1.5 times and anaerobic bacterial count increasing 2 times). 14 Cleveland et al (1997) reported a three times increase in needle stick injuries in dentists over the decade 1986 to 1995. 8 Coleman et al (2010) reported that the tank water supply (which is usually not potable), biofilms in ...