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Sterilisation And DisinfectionIn Orthodontics

Dr.Sandeep

Postgraduate

SVS Institute Of Dental Sciences

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contents• Introduction• Definitions• Pathways of transfer of infection• Classification • Sterilisation methods basics• Sterilisation of orthodontic armamentarium

– Pliers– Brackets– Molars bands– Arch wires– Pencils– TADS

• Hepatitis B• Conclusion

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Introduction • 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.

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How ? By What ?

Infection control

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• 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 tissues.

• 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.

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• Bactericidal/germicidal- are those which are able to kill bacteria.

• Bacteriostatic- are agents only that prevent the multiplication of bacteria which may however remain alive.

• Decontamination- refers to the process of rending an article or area free of danger from contaminants including microbial, chemical, radioactive and other hazards.

• Fumigation- exposure of an area or object to disinfectant, insecticidal or vermin killing fumes.

Text Book of Microbiology- Ananthnarayan,8th edition

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DENTIST

OTHER PATIENTS

PATIENT

DENTAL CLINIC

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Spaulding's Classification

first level – sanitization (thorough physical Cleaning).

second level – disinfection ( kills microorganisms only)

third level – sterilization ( kills all microorganisms & all spores)

Text book of Infection Control and occupational safety recommendations for oral health professionalS

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CDC classification

Critical instruments: those used to penetrate soft tissue or bone, or enter into or contact the bloodstream or other normally sterile tissue.

• 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 intact skin.

• e.g: external components of x-ray heads, blood pressure cuffs and pulse oximeters.

Centers for Disease Control and Prevention. Guidelines for infection control in dental health care settings—2003. MMWR 2003; 50(No. RR-17).

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Sterilisation

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Sterilising

methods

PHYSICAL

Sunlight

Drying

Heat

Filtration

Radiation

Ultrasonic and sonic vibration

CHEMICAL

Alcohols

Aldehydes

Dyes

Halogens

Phenols

Surface active agents

Metallic salts

Gases

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method Red heat Flaming Incineration Hot air oven

Temp/technique

Till red hot Just pass over flame

Burnt to ashes 160 deg

Time/duration

One hour

materials Loops,tips of forceps

Glass slidesscalpels

Soiled dressingPathological waste

Scalpels ScissorsForceps etc

Dry Heat

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Moist HeatAt temp Below 100 At temp of 100 At temp Above 100

PasteurisationInspissationVaccine bath

BoilingTyndallisationSteam steriliser

Autoclave

60 – 75 deg 100deg Temperature-1210C (2500F) Pressure -15 psi

Pasteurisation - 30 minInspissation – 30 min Vaccine bath – 60 min

Boiling -10-30 minTyndallisation – 20 minSteam steriliser – 90 min

15 – 20 mins

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Other physical

Filtration

Earthen ware

Asbestos filters

Sintered glass

Membrane filters

Radiation

Ionising Non ionising

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Guidelines For Orthodontic Armamentarium Sterilisation

• Minimal requirement for sterilising the orthodontic instruments are :– Ultrasonic – Dry heat steriliser– Autoclave

• 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.

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Orthodontic pliers

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Dry Heat Vs Moist Heat

50 ligature wire cutters

Group 1

25

Autoclave

0.025 mm wire

50 cuts

6/12 cycles

Group 2

25

Dry heat

0.025 mm wire

50 cuts

6/12 cycles

Effect of steam versus dry-heat sterilization on the wear of orthodontic ligature-cutting pliers; Ricardo J. Vendrel et al; AJODO 2002;121:467-71

SS

inserts

• Ultrasonic cycle for 5-10 min

• Rinsing with distilled water

• Drying with compressed air

• Lubrication with silicone based lubricants

• Dry heat sterilisation at 190 deg for 6-12 min

• Pliers should be open

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Orthodontic brackets

• Made from stainless steel• featuring a low profile catch that will not tear sterilisation

wrap. • Suitable for all types of sterilisation. • Compartments are permanently marked for tooth

identification.• Bracket Tray marked for 6 - 1 | 1 – 6,6 - 1 | 1 – 6• Band Tray marked for 1st and 2nd Molars and 1st and 2nd

Bicuspids. • Sold individually.

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Molar bands

• Most overlooked materials in orthodontics.

• Sterilisation of tried in preformed bands has received attention nowadays.

• 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.

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• During appliance placement several bands may be tried in the mouth before the appropriate size is selected.

Sterilisation of bands

autoclave

Dry heat

Glass bead

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Autoclave

200 molar bands u/l

Tried in patients

Disinfecttion by enzymatic

action

Autoclave

134deg 3 minInoculate in BHI medium

M. R. Fulford et al Decontamination of tried-in orthodontic molar bands : European Journal of Orthodontics 25 (2003) 621–622

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Dry heat

Ultrasonic cycle for 5

min

Rinsing with distilled water

Drying with compressed

air

Dry heat sterilisation at 190 deg for 6

min

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Glass bead

• 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 enough.

– 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 :90:243-49

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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

cross contamination

• Otherwise,in case of e chain spools it is better to cut little

extra than required and discard rest

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E chains in 2% glutaraldehyde

control 30 min 10 hrsFive cycle

30 min

144h/

6 days

Tensile strength

Failure loading

Jeffries et al;Effects of 2% alakline glutaraldehyde on e- chains;Angle ortho ;1990;61(1),25-30

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Vital defense E chains

10 min 1 hr 8hrs 48 hrs 7 days 14 days 28 days

Tensile loading

Cidex plus

Maylani B. Evangelista et al;Effect of Disinfecting Solutions on the Mechanical Properties of Orthodontic Elastomeric Ligatures:Angle Ortho, 77, (4), 2007

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Arch wires

• Arch wire sterilisation can ve done by routine 3 methods:

– Cold sterilisation

– Dry heat sterilisation

– Autoclaving

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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

NiTi wires

2% acidic glutaraldehyde

10 hrs

Chlorine dioxide

6 hrs

iodophors

10hrs

Effects of Cold disinfectants on the mechanical properties and surface topograph of niti arch wires:AJODO;1988;94;117-22

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6 orthodontic

wires

autoclaving

SEM study 3 point bending test

18 min 134 deg

Optical microscopy

Influence of autoclave on the surface parameters and mechanical properties of 6 orthodontic wires;EJO:2005;27(1);72-81

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• 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.

• Results:– 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.

Sunil Kapila, et al ;Load-deflection characteristics of nickel-titaniu alloy wires after clinical recycling and dry heat sterilization;AJODO;1992;102:120-6.

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• 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-then-disinfected/sterilized wires.

• 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

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Marking pencil

• Marking pencils can be potential source of cross contamination.

• 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

plastic.• cannot be cold sterilised as it contains ink.

Disinfection of permanent markers;JCO;1996:30(1) ;646-649

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• Probable solution may be use of ink containing alcohols.• Alcohols are considered as intermediate level

disinfectants.

• 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) ;307-310

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• 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 count.

• 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 disposable.

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TADS

• 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

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• Sterilisation of mini implants can be done by – autoclaving– 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.

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100 mini implants

50 control 50 test group

Autoclaved at 121 deg for 30 min

Fracture toughness test

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• 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

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Torque readings and lateral dispalcement values were recorded

30 mini implants

control

1 cycle

Autoclave

132 deg for 6 min

Test group

5 and 10 cycles

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• 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.

Sercan Akyalcin et al; Effects of repeated sterilization cycles on primary stability of orthodontic mini-screws;Angle Orthod. 2013;83:674–679.

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Hepatitis B

• 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

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Preventive measures

Vaccination of doctor and assistant

Medical history taking

Barrier techniques

Sterilisation•

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Hepatitis-B vaccination

• 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

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Do hepatitis b patients are contraindicated for orthodontic

treatment?• NO,

• proper barriers techniques and sterilisation procedures before and after treatment should be followed to prevent cross infection.

• And as they are not prescribed any systemic drugs there seems no contraindications.

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Dental impressions

• 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.

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conclusion

• “Prevention is better than cure” a proverb well suited to

sterilization.

• 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

professional demands.

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• 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 protect– Ourselves – Patients– Family and friends from cross infections.

04/11/2023 49Thank you…..