sterilisation in orthodonticsPresentation Transcript
Sterilisation And Disinfection
SVS Institute Of Dental Sciences
• Pathways of transfer of infection
• Sterilisation methods basics
• Sterilisation of orthodontic armamentarium
– Molars bands
– Arch wires
• Hepatitis B
• Microorganisms are ubiquitous
• Pathogenic microbes may be transmitted directly from
the dentist to the patient or from the patient to the
doctor, and indirectly from patient to patient.
• Thus ,it is necessary to remove them as they cause
contamination , infection and decay.
• This presents an enormous challenge in the current
scenario as it has been proved that blood and saliva are
high risk sources of contracting hepatitis b, human
immunodeficiency virus and herpes.
• Sterilization is defined as the process by which an
article, surface or medium is freed by all living micro-
organisms either in vegetative or spore state.
• Disinfection- means the destruction or removal of all
pathogenic organisms or organisms capable of giving
rise to infection.
• Antisepsis- used to indicate the prevention of infection,
usually by inhibiting the growth of bacteria in wounds or
• Antiseptics- Chemical disinfectants which can be safely
applied to skin or mucous membrane and are used to
prevent infection by inhibiting the growth of bacteria.
• Bactericidal/germicidal- are those which are able to kill
• Bacteriostatic- are agents only that prevent the
multiplication of bacteria which may however remain
• Decontamination- refers to the process of rending an
article or area free of danger from contaminants
including microbial, chemical, radioactive and other
• Fumigation- exposure of an area or object to
disinfectant, insecticidal or vermin killing fumes.
Text Book of Microbiology- Ananthnarayan,8th edition
first level – sanitization (thorough physical Cleaning).
second level – disinfection ( kills microorganisms only)
third level – sterilization ( kills all microorganisms & all
Text book of Infection Control and occupational safety recommendations for oral health professionalS
Critical instruments: those used to penetrate soft tissue or bone, or
enter into or contact the bloodstream or other normally sterile
• eg: scalpels,forceps.
Semi critical instruments: those that do not penetrate soft tissues or
bone but contact mucous membranes or non-intact skin.
• e.g: mirrors, reusable impression trays and amalgam condensers
Non critical instruments: those that come into contact only with
• e.g: external components of x-ray heads, blood pressure cuffs and pulse oximeters.
8/25/2013 9Centers for Disease Control and Prevention. Guidelines for infection control in dental
health care settings—2003. MMWR 2003; 50(No. RR-17).
method Red heat Flaming Incineration Hot air
Till red hot Just pass
Burnt to ashes 160 deg
materials Loops,tips of
At temp Below 100 At temp of 100 At temp Above 100
60 – 75 deg 100deg Temperature-1210C
Pressure -15 psi
Pasteurisation - 30 min
Inspissation – 30 min
Vaccine bath – 60 min
Boiling -10-30 min
Tyndallisation – 20 min
Steam steriliser – 90 min
15 – 20 mins
Guidelines For Orthodontic Armamentarium
• Minimal requirement for sterilising the orthodontic
instruments are :
– Dry heat steriliser
• Other than this chemical sterilisation with alcohol and
other vapours can be done for the instruments which are
not in direct contact with blood or saliva.
Dry Heat Vs Moist Heat
50 ligature wire
0.025 mm wire
0.025 mm wire
8/25/2013 18Effect of steam versus dry-heat sterilization on the wear of orthodontic ligature-cutting pliers;
Ricardo J. Vendrel et al; AJODO 2002;121:467-71
• Ultrasonic cycle for
• Rinsing with distilled
• Drying with
• Lubrication with
• Dry heat sterilisation
at 190 deg for 6-12
• Pliers should be
• Made from stainless steel
• featuring a low profile catch that will not tear sterilisation
• Suitable for all types of sterilisation.
• Compartments are permanently marked for tooth
• Bracket Tray marked for 6 - 1 | 1 – 6,6 - 1 | 1 – 6
• Band Tray marked for 1st and 2nd Molars and 1st and
• Sold individually.
• Most overlooked materials in orthodontics.
• Sterilisation of tried in preformed bands has received
• In orthodontic clinical practice the attachments on
posterior teeth are commonly welded to stainless steel
bands and cemented into position within the mouth.
• Unlike directly bonded attachments, where one size fits
all, bands have to be selected according to the size of
the tooth to which they are to be cemented.8/25/2013 20
• During appliance placement several bands may be tried
in the mouth before the appropriate size is selected.
134deg 3 min
M. R. Fulford et al Decontamination of tried-in orthodontic molar bands : European
cycle for 5
at 190 deg
for 6 min
• Smith reported that glass bead steriliser can be used
effectively to sterilise the tried in bands.
• He recommended :
– Single band for 1 min in bead steriliser due to
fluctuations in temperatures other wise 45 sec is
– Temp : 225 – 250 deg.
– 5 or more bands need to double the time.
– Steriliser with deep and narrow wells are preferred
over shallow ones as
SMITH.G; GLASS BEAD STERILISATION OF BANDS; AJODO September 1986
Elastomeric ligatures and chains
• These are not chemiclaved as they are known to alter
the physical properties
• Alcohol wipes are also not recommended as they are not
so effective in blood and saliva
• Single patient packs are best suitable for preventing
• Otherwise,in case of e chain spools it is better to cut little
extra than required and discard rest
E chains in 2%
control 30 min 10 hrs
8/25/2013 26Jeffries et al;Effects of 2% alakline glutaraldehyde on e- chains;Angle ortho
10 min 1 hr 8hrs 48 hrs 7 days 14 days 28 days
8/25/2013 27Maylani B. Evangelista et al;Effect of Disinfecting Solutions on the Mechanical Properties of
Orthodontic Elastomeric Ligatures:Angle Ortho, 77, (4), 2007
• Arch wire sterilisation can ve done by routine
– Cold sterilisation
– Dry heat sterilisation
After the disinfection period wires were subjected to tensile
bending ,and laser tests .
Results show no significant changes in fundamental
stiffness/strength of wires after disinfection
Effects of Cold disinfectants on the mechanical properties and surface topograph of niti
18 min 134
8/25/2013 30Influence of autoclave on the surface parameters and mechanical properties of 6 orthodontic
• Ten NiTi wires were used in the study per each group.
• Group 1 clinical recycling and dry heat sterilisation
• Group 2 only DHS
• Clinical recycling was done after 1 cycle.
– showed that force levels increased after CR for NiTi wires
between pre tx and first cycle.
– Thus suggesting that CR appears to reduce pseudoplasticity and
pseudoelasticity of NiTi wires increasing their stiffness.
8/25/2013 31Sunil Kapila, et al ;Load-deflection characteristics of nickel-titaniu alloy wires after
clinical recycling and dry heat sterilization;AJODO;1992;102:120-6.
• a study was conducted in which CR then sterilised and
as received wires of different types SS,NiTi,TMA wires
were analysed for change in the properties.
• Different test like:tensile loading,3 point bending
test,laser topographic study were performed.
• Load/deflection and tensile tests showed no clinically
significant difference between as-received and used-
• These results suggest that nickel-titanium arch wires can
be recycled at least once.
The effect of clinical use and sterilisation of selected orthodontic archwires :AJODO;1992;102:1539
• Marking pencils can be potential source of cross
• Sterilisation options for these pencils are
– EO gas
– Alcohol wipes
• These pencils cannot be autoclaved.
• Use of permanent marking pens can also be considered
for marking arch wires.
• But these pens cannot be autoclaved as it is made of
• cannot be cold sterilised as it contains ink.
Disinfection of permanent markers;JCO;1996:30(1) ;646-649
• Probable solution may be use of ink containing alcohols.
• Alcohols are considered as intermediate level
• Study was conducted using red,blue,black permanent
markers with alcohol .
• Alcohol content ranging from 50-80%.
Marking pencils as potential source of cross contaminaton;JCO;1998:32(5)
• Results suggest that alcohol are not so efficient in
preventing cross contamination.but drying period of 10
min between 2 patients showed a decrease in bactrial
• This suggests that pens after use should be left capped
for 10 min to dry.
• Finally,the best method to prevent cross contamination is
use of inexpensive marking pencils which are
• Acc to CDC,placement of TADS is a surgical procedure
and nedd high level of sterilisation.
• Following are the requirements for procedure:
– Surgical hand antiseptic
– Surgical gloves
– Irrigant devices
– Sterile instruments
– Sterile implant
• Sterilisation of mini implants can be done by
– Dry heat sterilisation
• Dry heat strilisation should be done with caution as the
implant cannot tolerate high temp.
• And should be done with an temp indicators to identify
when the ideal temp has reached for sterilsation.
Autoclaved at 121
deg for 30 min
• The results of this study suggest that mini-implants can
be safely sterilized, with the method used in this study.
• This will lead to no clinically signiﬁcant changes to their
resistance to fracture.
Claudia et al; Effect of autoclaving on the fracture torque ofmini-implants used for orthodontic anchorage:Journal
of Orthodontics, Vol. 38, 2011, 15–20
Torque readings and lateral dispalcement values were
132 deg for 6
5 and 10
• Repeated cycles of sterilization altered the surface
characteristics of the mini-screws, as evidenced by the
significant changes in their maximum insertion torque.
• sterilization cycle as a main effect did not significantly
affect lateral displacement force values.
• study did not indicate major structural damage to the
mini-screws that may affect their clinical stability and
consistency as they are sterilized up to 10 cycles.
8/25/2013 41Sercan Akyalcin et al; Effects of repeated sterilization cycles on primary stability of orthodontic mini-
screws;Angle Orthod. 2013;83:674–679.
• The most common inflammatory disease of the liver is
due to hepatitis B (HBV).
• HBV is 50 to 100 times more infectious than HIV and is a
major occupational risk for physicians, surgeons .
• according to the studies conducted orthodontist exhibits
the second highest incidence of HBV.
JIOS;hepatitis b facts and concerns to orthodontist in india
Vaccination of doctor and assistant
Medical history taking
• Three doses are generally required to complete the
hepatitis B vaccine series, although there is an
accelerated two-dose series for adolescents.
– First Injection - At any given time
– Second Injection - At least one month after the first dose
– Third Injection - Six months after the first dose
– Booster dose – every five years
Do hepatitis b patients are
contraindicated for orthodontic
• proper barriers techniques and sterilisation procedures
before and after treatment should be followed to prevent
• And as they are not prescribed any systemic drugs there
seems no contraindications.
• Common disinfecting solutions used for impressions are
– 1% naocl
– Sodium dichlolroisocyanurate
– 2% glutaraldehyde
• Rinse the impression under running water
• Immerse in disinfectant for 10 min
• Rinse under water
• Ready for model processing
• In case of hepatitis b infected patients casts should be
poured with gypsum containing 0.25% chloramines.
• ―Prevention is better than cure‖ a proverb well suited to
• Thorough understanding of the application of sterilization
will help ensure safety from the invisible but deadly world
of microbial pathogens.
• Hence utilization of proper sterilization, disinfectants and
aseptic procedures help us achieve the safety of our
• All the above discussed sterilisation and disinfection
methods and the studies conducted to evaluate their
effects on mechanical and physical properties conclude
that none of the properties are effected.
• Thus sterilisation guidelines should be maintained to
– Family and friends from cross infections.