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From: TSS ()
Subject: Pre-sterilisation cleaning of re-usable instruments (TSE)
Date: July 13, 2007 at 2:24 pm PST

Pre-sterilisation cleaning of re-usable instruments
in general dental practice

J. Bagg,1 A. J. Smith,2 D. Hurrell,3 S. McHugh4 and G. Irvine5
Objective This study examined the policies, procedures, environment
and equipment used for the cleaning of dental instruments in general
dental practice.
Materials and methods A total of 179 surgeries were surveyed. This
was an observational based study in which the cleaning processes
were viewed directly by a trained surveyor. Information relating to
surgery policies and equipment was also collected by interview and
viewing of records. Data were recorded onto a standardised data collection
form prepared for automated reading.
Results The BDA advice sheet A12 was available in 79% of surgeries
visited. The most common method for cleaning dental instruments
was manual washing, with or without the use of an ultrasonic bath.
Automated washer disinfectors were not used by any surgery visited.
The manual wash process was poorly controlled, with 41% of practices
using no cleaning agent other than water. Only 2% of surgeries used
a detergent formulated for manual washing of instruments. When
using ultrasonic baths, the interval that elapsed between changes of
the ultrasonic bath cleaning solution ranged from two to 504 hours
(median nine hours). Fifty-eight percent of surgeries claimed to have
a dedicated area for instrument cleaning, of which 80% were within
the patient treatment area. However, in 69% of surgeries the clean
and dirty areas were not clearly defi ned. Virtually all cleaning of dental
instruments was undertaken by dental nurses. Training for this was
provided mainly by demonstration and observed practice of a colleague.
There was little documentation associated with training. Whilst
most staff wore gloves when undertaking manual cleaning, 51% of
staff did not use eye protection, 57% did not use a mask and 7% used
waterproof overalls.
Conclusions In many dental practices, the cleaning of re-usable
dental instruments is undertaken using poorly controlled processes
and procedures, which increase the risk of cross infection. Clear and
unambiguous advice must be provided to the dental team, especially
dental nurses, on appropriate equipment, chemicals and environment
for cleaning dental instruments. This should be facilitated by appropriate
training programmes and the implementation of quality assurance
procedures at each stage of the cleaning process.


The decontamination of re-usable medical devices is a key element
of infection control in clinical settings. The importance
of cleaning such devices as a means of preventing cross infection
has been reported in relation to diverse items of equipment
in many areas of clinical practice. These have included
ophthalmology,1 gastroenterology,2 vascular surgery,3 tourniquets4
and dental surgery.5-9
More recently, the emergence of transmissible spongiform
encephalopathies (TSEs), such as variant Creutzfeldt-Jakob
disease (vCJD), has re-emphasised the importance of thorough
cleaning of used devices prior to steam sterilisation10,11
since the abnormal form of prion protein, which is responsible
for these diseases, is less susceptible to denaturation by heat.
Thus, effi cient cleaning of instruments is believed to be a key
procedure for reducing the potential risks of onward transmission
of vCJD.10-12 Effective cleaning is also vital to ensure
microbial inactivation since retention of organic or inorganic
debris may compromise subsequent disinfection or sterilization
processes.13-16 The cleaning of re-usable dental instruments is
also important to ensure device longevity and functionality,
removal of chemical residues and compliance with medicolegal
One mechanism for improving the quality of instrument
decontamination is to centralise re-processing in
well-equipped sterile services departments, which are operated
by highly trained staff, using validated equipment, in
an accredited quality management system. In the UK, this
approach has been applied in the acute hospital sector. The
problem with this centralised model in dentistry is that the
high volume of instruments used by dental surgeons provides
a signifi cant logistical challenge. It is therefore likely that
instrument decontamination in general dental practice will
continue to be undertaken at a local level. It is important that
all processes involved in decontamination are undertaken to
a high standard, but unfortunately there has been little evidence
to indicate the robustness of these procedures in dental
practice, as highlighted in a systematic review.20 In order to
address this problem, a large observational study of decontamination
procedures in general dentistry in Scotland was
devised and has recently been completed. This paper reports
the data generated by the study in relation to procedures used
by dentists for pre-cleaning of instruments prior to the sterilisation


snip. ...

In conclusion, many of the procedures used for the cleaning
of re-usable dental instruments in general dental practice
do not conform to extant guidance and increase the risk
of transmission of infection. This is of particular concern,
since cleaning is a key stage in the sterilisation process and in
reducing the risk from onward transmission of vCJD. Where
possible, practices should review the many options available
to them for the reprocessing of dental instruments. In some
circumstances this may involve the use of centralised reprocessing
facilities35 or single use instruments. Other options may
involve a compromise with local reprocessing of expensive
devices such as dental handpieces and centralised reprocessing
of other instruments. If local reprocessing of dental instruments
is to continue in general dental practice, clearly much
work is needed to help the dental team improve the cleaning
process for dental instruments. This should take the form of
education and training programmes and the development of
a clearer management process using quality assurance principles.
The fi ndings of this survey also have profound fi nancial
implications for dental practices, not least in the provision of
dedicated decontamination areas and automated washer disinfectors.
This also represents an opportunity for improvement,
especially with the planning of new dental units. However, if
the opportunity is to be fully realised, there is a requirement
for suffi cient infrastructure to support practitioners in implementation
of improvements in local decontamination,29 for
example expert review of new buildings, commissioning and
testing of decontamination equipment. Practice-friendly guidance
to help practitioners meet the various regulatory requirements
for cleaning dental instruments is essential if progress
is to be made in this very important area of clinical practice.
This research was supported by a grant from the Scottish Executive Health
Department. Funding for the training of the survey team members was provided
by NHS Education for Scotland. The authors thank Mr Ray Watkins,
Chief Dental Offi cer for Scotland and Dr Jim Rennie, Postgraduate Dental
Dean for Scotland for support of the study, the members of the survey teams
and the dental practitioners and nurses who agreed to be surveyed.


full text ;

It is all about motivation

I am occasionally asked by actors and actresses what motivation
their characters have for various lines that I have written
for them in plays and the like. It is a bit of a cliché but there
is usually a good reason for the question as the performer is
attempting to understand their character better and provide an
improved performance for the audience.
But motivation often involves fi nishing the sentence, or at
least the sentiment behind it. In acting it is sometimes forgivable,
indeed sometimes it adds value for the observer when
everything is not spoken or revealed. But there does not seem
to be much of a case for it in health care. I have in mind the
recent advice issued by the various UK Departments of Health
in relation to the single-use of endodontic instruments.
One has to assume that the information is imparted in good
faith, since why else would a state department issue such advice
(it is advice, note, not guidance or direction). Advice nonetheless
that ‘dentists are expected to follow’? But the manner in
which it was announced and the scientifi c basis on which it is
apparently founded both give rise to suspicions and to distrust.
It is probably just poor logistics but the result is that it opens
the way to questions over motivation.
Firstly to the manner in which it was announced; it transpires
that all policy developments and guidance in relation to vCJD
has to be fi rst reported to Parliament before any other communication
can take place. This was a commitment made by
John Reid when he was Secretary of State for Health and supported
by the then current Ministers. This explains why BDA
members contacted us the same morning of the announcement
asking why the Association had not let them know. We had to
reply that it was because we did not know about it either until
we heard it on BBC Radio 2. Important as it is that 630 MPs
(or however many were in the Chamber that session) are the
fi rst to know, presumably patients in surgeries with the radio
on and endodontic instruments in their root canals would also
think it a matter of some importance. With hindsight, can our
elected representatives really believe that this is the best way
to deal with matters of health care?
The science on which this advice is based brings forth a further
clutch of questions. We are told that, ‘early results from
studies in mice suggest that TSE (Transmissible Spongiform
Encephalopathies, the group of prion diseases that include BSE,
CJD, vCJD and scrapie) infectivity can be found in dental tissues’.
The studies, early results or not, are not published so none
of us can assess that risk independently.
On the one hand this may seem reasonable since we are constantly
being entreated ourselves to follow best practice as
indicated by evidence-based studies. We have to take the Chief
Dental Offi cers’ words at face value, since we have no other
base on which to judge them, as indeed presumably they have
had to take the words of others above them. But on the other
hand this is about calculated risk assessment. Someone, somewhere
has taken a decision on the basis of what is known to
date and the extent to which they assess that to be a threat to
the population. Or in this case a ‘theoretical’ threat. Once again
though, we are denied the knowledge of the motivation. Is the
advice given on a defensive basis so that if in years to come
patients can show that they have contracted a TSE disease from
endodontic treatment they will be able to sue the government
because it failed to act on the scientifi c advice of the time? Or
is the advice given on the basis that such potential litigation
is then passed to the individual dentist? Alternatively, is the
advice just on the basis of taking good care of the population?
It might be all or any of these but we have to guess and it is the
guessing that substantially increases the risk of distrust.
All of this, sadly, obscures what one hopes is the real motivation
behind the advice, which is that if there is a risk then it is
wise to take sensible precautions. The issues of who pays the
additional costs and the environmental questions of reamer and
fi le-mountains all need to be considered in the risk evaluation
too. Have they been? Confl icting reports on the possibility or
not of fi nancial compensation for those dentists offering NHS
dentistry have served only to add further confusion, rumour
and annoyance.
The handling of the matter as a whole makes one seriously
doubt that any kind of global view has been taken before the
advice has been rushed out. We may, as a profession, be accused
of starting to get paranoid about having matters forced upon
us with little or no consultation, little or no notice and precious
little respect for our professionalism but is it really surprising?
Handled logically, with proper sequencing this development
could have been, should have been, a triumph for good sense,
measured response and excellence in health care. Instead it is
an all too familiar shambles. How many more will there be?
Stephen Hancocks OBE
DOI: 10.1038/bdj.2007.422
It is all about motivation

Dental treatment and risk of variant CJD –
a case control study
D. Everington,1 A. J. Smith,2 H. J. T. Ward,3 S. Letters,4 R. G. Will5 and J. Bagg6
Objective Knowledge of risk factors for variant CJD (vCJD) remains
limited, but transmission of prion proteins via re-useable medical devices,
including dental instruments, or enhanced susceptibility following trauma
to the oral cavity is a concern. This study aimed to identify whether
previous dental treatment is a risk factor for development of vCJD.
Design Case control study.
Methods Risk factor questionnaires completed by interview with
relatives of 130 vCJD patients and with relatives of 66 community and
53 hospital controls were examined by a dental surgeon. Responses
regarding dental treatments were analysed.
Results We did not fi nd a statistically signifi cant excess of risk of vCJD
associated with dental treatments with the exception of extractions in
an unmatched analysis of vCJD cases with community controls
(p = 0.02). However, this result may be explained by multiple testing.
Conclusions This is the fi rst published study to date to examine
potential links between vCJD and dental treatment. There was no
convincing evidence found of an increased risk of variant CJD
associated with reported dental treatment. However, the power of the
study is restricted by the number of vCJD cases to date and does not
preclude the possibility that some cases have resulted from secondary
transmission via dental procedures. Due to the limitations of the data
available, more detailed analyses of dental records are required to fully
exclude the possibility of transmission via dental treatment.


Many studies have searched for risk factors for the development
of different types of CJD, such as diet, exposure to
animals, surgical treatment, including dentistry, and occupational
exposures. A retrospective case control study15 of 60
defi nite cases of sporadic CJD, occurring in Japan between
1975 and 1977 found no association with extractions of maxillary
or mandibular teeth. An analysis of 26 sporadic CJD
cases and 40 matched controls from the United States16 failed
to discover a signifi cant odds ratio for endodontic surgery,
though these workers did note statistically signifi cant odds
ratios for intraocular pressure testing, injury to or surgery on
the head, face or neck and trauma to other parts of the body.
However, these fi ndings suffer from low statistical power and,
in the case of the Japanese paper, information was requested
for extractions only during the fi ve year period prior to onset.
This paper attempts to identify an association between vCJD
and reported dental treatment.
Comparison of the reported dental histories of cases and
controls found that extractions were the only dental risk factor
that reached statistical signifi cance (at the 5% level) in the
unmatched analysis with community controls. This may be a
result of multiple testing especially as there are fewer extractions
in the cases than in the hospital controls. It is likely that
the majority of vCJD cases in this cohort were infected through
eating BSE contaminated meat products. Therefore, it is diffi -
cult to detect a small subgroup that may have been infected by
secondary transmission, as in this study, through dentistry.
There are a number of limitations to this study, most importantly
relying on reported data from relatives and the relatively
small numbers of cases and controls resulting in low
power to detect statistical differences. Recruitment of controls
has been problematic,17 although every effort was made to
maximise this group. Selection of controls was not matched for
demographic and socio-economic factors for dental attendance
and this may have resulted in bias. It is possible that some of
the responses of ‘no known treatment’ refl ect poor knowledge
or recall on the part of the relatives. This would reduce the
power of the study to pick up signifi cant differences between
groups, but not necessarily introduce bias.
Whilst these preliminary data on a topic of great concern
for public health do not provide evidence supporting reported
dental work as being a major route of transmission of the BSE
agent to humans to date, they do not preclude the possibility
that some vCJD cases have been infected by this route.
Furthermore, the incubation period following infection by
a peripheral route may be relatively long and therefore the
period of observation to date of potential secondary transmission
of vCJD may be too short to detect cases.
A more detailed study of previous treatment based on reviewing
actual dental records rather than relying on reported treatments
is required to gain a wider insight into the dental history
of both cases and controls. We are currently investigating the
possibility of examining dental records of vCJD cases and a
larger group of unmatched controls.18
The National CJD Surveillance Unit is funded by the Department of Health
and the Scottish Executive Department of Health. The sponsors of the study
had no role in study design, data collection, data analysis, data interpretation,
or in the writing of the report. We are also grateful to the families of
cases, without whose co-operation this study would not have been possible.

Subject: Position Statement vCJD and Dentistry SEAC UPDATE DISTURBING
Date: June 9, 2007 at 7:52 am PST;article=356;title=CJD%20DISCUSSION%20BOARD;pagemark=25;article=357;title=CJD%20DISCUSSION%20BOARD;pagemark=25


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