The advent of effective bench-top sterilisers was a giant leap forward in infection control and instrument reprocessing in dental surgeries. Since then, sterilisers have evolved significantly, with many countries now mandating the use of so-called class B sterilisers that can create a vacuum in the steriliser's chamber prior to injecting steam for maximum effectiveness.

1. 122 Australasian Dental Practice January/February 2017
infection | CONTROL
T
he advent of effective bench-
top sterilisers was a giant leap
forward in infection control
and instrument reprocessing in
dental surgeries.
Since then, sterilisers have evolved
significantly, with many countries now
mandating the use of so-called class B
sterilisers that create a vacuum in the
steriliser’s chamber prior to injecting
steam for maximum effectiveness. The
exclusive B-Type cycle of the Lisa Auto-
matic steriliser from W&H goes a step
further with automatic load sensing tech-
nology that ensures all loads (including
light loads and fast cycles) undergo the
appropriate sterilisation cycle.
This is particularly important, as even
with pre-vacuum B Type cycles, incorrect
loading or overloading of the chamber can
interfere with the ability of the steam to
fully penetrate hollow and wrapped loads.
Moist heat in the form of saturated
steam under pressure is by far the most
reliable medium known for the destruc-
tion of all forms of microbial life and
ADA Infection Control Guidelines (2015)
state that bench top steam sterilisers (also
called autoclaves) are the most reliable
and efficient sterilising units for use in
office-based practice.
Safe steam sterilisation begins by
demonstrating that the selected cycle is
compatible with the load to be processed
(i.e. hollow, textile, implantology cassettes,
etc). ADA Infection Control Guidelines
(2015) recommend the use of B class
cycles for hollow objects where the
ratio of the length of the hollow por-
tion to its diameter is more than 1:5.
The W&H Lisa steriliser has made-to-
measure automatic cycles that reduce the
cycle time depending on the number and
type of items to be sterilised - the smaller
the load (i.e. number of instruments), the
quicker the cycle.
This has a number of benefits for the
dental practice, namely:
• Faster cycles, means less energy used;
• Time savings of 15 to 25 minutes for
these smaller loads for quicker instru-
ment turnaround; and
• Valuable instruments are less exposed
to heat, increasing their lifespan.
Record keeping
The other advantage of a modern auto-
clave such as the Lisa Automatic is in
the area of record keeping and instrument
tracking. The Lisa steriliser automatically
records Cycle parameters via an on-board
digital card or it can be connected via an
ethernet cable to a PC
NOTE! Recording this information
for each cycle (which the Lisa does
automatically) is mandatory compli-
ance for Australian Standards AS4815
and AS4187.
The W&H Lisa
steriliser includes user authen-
tication which makes it possible to
identify the operator who releases the load
via username and (optionally activated)
4-digit pin code for additional security.
Once again, this user requirement is
mandatory for compliance with AS4815
and AS4187.
The menu is integrated in Lisa’s
firmware and is therefore directly acces-
sible from the steriliser’s touch-screen.
No additional software is needed and
record keeping does not require manually
recording cycle data in a ledger; conse-
quently there is no risk of missed entries
or transcription errors.
Ensure your steriliser complies

2. January/February 2017 Australasian Dental Practice 123
As an added safeguard, the Load
release function on the Lisa will only be
authorized if the sterilisation cycle has
completed successfully.
An optional LisaSAFE bar code printer
will produce bar-coded labels for pouches,
but again, it will not produce a label if a
the cycle is not successfully completed.
This type of instrument tracking is
being implemented in both public and
private practices to safeguard patients
and staff, provide confidence in infection
control protocols and provide a medico-
legal paper trail, linking instruments to
individual patients and procedures.
All of these features have made the
Lisa steriliser a popular choice in both
small and large private and public
dental clinics committed to staff and
patient safety.
This provides great peace of mind,
however, a properly trained operator must
still oversee the following sterilisation
processes which should be documented in
the practice’s training manual:
• The steriliser operator must check the
cycle parameters (not less than 134°C,
not less than 3 minutes, not less than
2.03BAR pressure);
• The operator must check packages or
pouches are dry when removed from
the chamber; and
• The operator must check all chemical
indicators.
Validation and testing
Effective sterilisation must be con-
sistently reliable, predictable and
measureable to ensure all parameters have
been met before loads are released. While
periodic validation of the steriliser by an
authorised service technician (on commis-
sioning and annually) and regular HELIX
and Bowie Dick challenge processes
provide an independent benchmark, it
is essential that each and every load is
checked by the operator as described here.
HELIX tests ensure the steriliser can
remove air from within hollow instru-
ments - steam may not displace trapped
air, so the Helix vacuum test is essential.
A vacuum test should be run and the steri-
liser verified at the first cycle of the day
(check that the chamber is dry and cool),
prior to the HELIX test to ensure the
chamber is sealed.
A test cycle should be completed and
the HELIX test result verified prior to
the first load processing cycle for B-cycle
(and also for S-cycle autoclaves claiming
removal of air from ‘Hollow A’ items i.e.
dental handpieces).
A HELIX test verifies whether air has
been removed effectively from hollow
items, such as the pipes within dental
handpieces. It can be used in a separate
test cycle or included along with a regular
load. In contrast, a Bowie-Dick test is
always used with a special cycle where no
other items are present.
For more information on Lisa sterilisers,
contact A-dec Australia on 1800-225-010
for your nearest A-dec dealer.
infection | CONTROL
A HELIX test verifies whether
air has been removed effectively
from hollow items, such as the
pipes within dental handpieces.
Handpiece maintenance units
such as the W&H Assistina can
ensure handpieces are clean and
well lubricated prior to sterilisa-
tion for best practice hygiene.