INFECTION CONTROL

UNDER THE GUIDANCE:Prof.Dr.C.S. Saimbi(H.O.D)Dr.Vikash Kumar(Asst.Prof)

PRESENTED BY –Dr.SONI BISTA

(1st year PG student)

Periodontology and Oral Implantology

InfectionHand hygienePPEvaccinationSterilizationcleaningDisinfectionAsepsisOperatory room procedureWaste management

INFECTION CONTROL“exposure control plan” _OSHA

WHO __ “Infection prevention and control measures aim to ensure the protection of those who might be vulnerable to acquiring an infection both in the general community and while receiving care due to health problems, in a range of settings.”

INFECTION OF CONCERN IN DENTISTRY

TRANSMITTED BY INHALATION:

Varicella virus

Chicken pox

Paramyxovirus

Measles & Mumps

Rhino/adeno virus

Common cold

Mycobacterium

Tuberculosis

Rubella German MeaslesCandida sp Candidiasis

Hepatitis B,C,D Hepatitis Herpex simplex I Oral herpes, herpetic

whitlowHerpex simplex II Genital herpes

HIV AIDS & ARCNeisseria

gonorrhoeaeGonorrhoeae

Treponema pallidum

Syphilis

S.aureus/ albus Wound abscess

TRANSMITTED BY INOCULATION:

CROSS INFECTIONHepatitis AHepatitis BPersonnel with acute or chronic hepatitis B surface antigenemia who do not perform exposure-prone proceduresPersonnel with acute or chronic hepatitis B antigenemia who perform exposure-prone proceduresHepatitis C

Hands (herpetic whitlow)

HIV

Rubella

Staphylococcus aureus infection

Active, draining skin lesions

Streptococcal infection, group A

Tuberculosis

CHAIN OF TRANSMISSION

STRATEGY TO ACHIEVE INFECTION CONTROL

1)HAND HYGEINE2)PPE3)STERILIZATION4)DISINFECTION5)CLEANING6)WASTE MANAGEMENT

REGULATORY AGENCYdeveloping safe guidelines to prevent and control the spread of infectious diseases

Maintaining minimum health and Safety standards for employees

HAND HYGEINE

IGNAZ SEMMELWEIS (1947): value of hand washing and fingernail scrubbing

CDC :spread of pathogens can prevented by effective hand washing

HAND CLEANSERSCHLORHEXIDINE BASED –Contain 2- 4%

chlorhexidine gluconate with 4% isopropyl alcohol. Special cleansing (e.g.: for surgery, glove leaks, or when clinician experiences injury).

POVIDONE IODINE – contain 7.5-10% povidone iodine, used as a surgical hand scrub.

PARACHLOROMETEXYLENOL(PCMX) – Bactericidal and fungicidal at 2%

concentration.ALCOHOL HAND RUBS- ethyl alcohol

and isopropyl alcohol (70% conc.) Germicidal

PERSONAL PROTECTION EQUIPMENTS (PPE)

•Specialized clothing worn by a health personnel for protection against hazards.•Creates PHYSICAL BARRIER between infection and health personnel.

Glove Type Comments Common Materials

Patient examination gloves

•Class I medical device

o Sterile and nonsterile

o Single use disposable

•Natural rubber latex•Nitrile•Vinyl (PVC)

Surgeon’s gloves

•Class I medical devices

o Sterileo Single use

disposableo No lubricating

or dusting powder used in these glove

o Gloves for dental surgery may be thicker than standard surgeon’s gloves

•Natural rubber latex•Nitrile•Combinations of latex and/or synthetics

1) GLOVES

Steps in gloving…

CONTACT DERMATITIS AND LATEX HYPERSENSITIVITYContact dermatitis is classified as1. Irritant 2. AllergicLatex hypersensitivity

PRECAUTIONS TAKEN FOR LATEX ALLERGIC PATIENTS

Respiratory or anaphylactic symptoms First appointment of the day Emergency treatment kits

2) GOWNSGown type Situation and

RationaleCotton/linen, reusable or disposable, long-sleeved isolation gowns

Use if contamination of uniform or clothing is likely or anticipated

Fluid resistant isolation gown or plastic apron over isolation gown 

Use if contamination blood or body fluids is likely or anticipated

Fluid impervious gowns e.g., Gortex®  

Use if extended contact or large volume exposure (e.g., large volume blood loss)

3)MASKSTypes:1. Surgical masks 2. Isolation masks

Made up from a melt blown placed between non-woven fabric

Layers of a Mask1. an outer layer2. a microfiber middle layer - filter large wearer-

generated particles3. a soft, absorbent inner layer - absorbs

moisture.Available in 2 sizes: regular and petite.

N95 particulate respirator

Surgical maskNIOSH approved N95 respirator

CAUSES OF EYE DAMAGE: 1. Aerosols and

spatter2. Sharp debris

projected from mouth while using air turbine handpiece, ultrasonic scaler may cause eye injury.

3. Injuries to eyes of patients caused by sharp instruments especially in supine position

4) EYE WEAR

Most hospitals have their own policies regarding footwear. Footwear with open heels and/or holes across the top can increase the risk of harm to the person wearing them due to more direct exposure to blood/body fluids or of sharps being dropped for examples.

5)FOOT WEAR

5)BONNETS

Wearing PPE is an important component of Standard and Transmission-based Precautions

RECOMMENDED VACCINES FOR HEALTHCARE

WORKERS(CDC)1)HEPATITIS B2)FLU (INFLUENZA)3)MMR4)CHICKEN POX5)TETANUS6)MENINGOCOCCAL

NEEDLE STICK INJURYPRECAUTIONS:

1) NEEDLE COVERED2) HANDLING3) NO RECAPPING WITH BOTH HANDS4) UNCAPPED NEEDLE NOT TO ASSISTANT5) NO BREAKING/BENDING6) SAFELY RECAPPINGRISK (Elise M. ,2000)1)HBV a)e antigen

+ve:30% b)e antigen –ve:1-

6%2)HepC : 1-8%3)HIV : 0.3%

POST ACCIDENTAL MANAGEMENT REMOVE GLOVES

WASH SITE WITH RUNNING WATER +SOAP

INFORM PATIENT + TAKE BLOOD SPECIMEN OF BOTH

HBV PROPHYLAXIS

clinician (–)vaccine clinician (+)vaccineHBIG within 48 hours if Ab titre >100 IU/L:

Hbv vaccine course no further t/m if Ab titre <100 IU/L:

booster dose

HIV POST EXPOSURE CHEMOPROPHYLAXIS

BASIC(28 DAYS) ZIDOVUDINE+LAMIVUDINE 600mg/day(300mg BID,200mg/100mg 4

hourly)+150mgEXPANDED(28 DAYS) AS ABOVE +INDINAVIRE 800mg, 8 hourly…750mg TID/200mg BID

Neelima Malik:textbook of oral and maxillofacial surgery

STERILIZATION Process that eliminates (removes) or kills

(deactivates) all forms of life and other  biological agents  including transmissible

agents (such as fungi , bacteria, viruses, prions,

spore forms, unicellular eukaryotic  organisms) present in a specified region,

such as a surface, a volume of fluid, medication, or in a compound such as biological culture media. _”WHO”

Distruction of all life forms_Ronald and Luftig

APPLICATION1.FOODS: CANNING(Nicolas Appert) FOOD

IRRADIATION

2.MEDICINE AND SURGERY: 3.SPACECRAFT:

HISTORY3000 BC_Use

of antisepticsIrrigation of wounds..

MODERN ERA:

Handwashing Pasteurization Process steam sterilizer

Fingernail Scrubbing (autoclave)

1)Ignaz Semmelweis 2)louis Pasteur 3)Joseph Lister (1847) (1862) (1876)

PRINCIPLES OF STERILIZATION1. All instruments should be thoroughly

cleaned, blood and debris should be removed before sterilization

2. Sterilizing agents( heat, steam, gas) should contact every surface of each item to be sterilized

3. All sterilizing equipments must be regularly serviced and maintained by qualified engineers.

4. Manufacturers instruction should be strictly adhered to for its operation and maintenance.

William Rutala (1994) American Physician working with the CDC Characteristics of an Ideal Sterilization Method

1.High efficacy 2.Rapid activity 3.Strong penetrability 4.Material compatibility 5.Nontoxic6.Organic material resistance7.Adaptability8.Monitoring capability9.Cost-effectiveness

A RATIONALE APPROACH TO DISINFECTION AND STERILIZATION

1)CRITICAL OBJECTS:Which enter sterile tissue/vascular systemSuch as surgical instruments, GI endoscopes.

2)SEMICRITICAL OBJECTS:That touches mucous membrane/skin that is not intact.Such as water syringe,mouth mirror, dental handpieces

3)NONCRITICAL OBJECTS:That touch only intact skin. Such as xray head,chairs,stethescope,etc

EH.SPAULDING believed that how an object will be disinfected depended on object’s intended use:

HOT AIR OVEN•Used to sterilize items which cannot be penetrated by steam/which donot get damaged by high temperature.

USES:1. Glassware such as test tubes2. Surgical instruments like

forceps,scapels,scissors..3. Oily fluids such as oils,fats4. Chemicals such as powders.

Temperature and time:˚C min160

60 170

40180

20

STERILISATION CONTROL:Thermocouples/spores of nontoxigenic strain of clostridium tetaniBrown’ tube with green spot

Sterilization by dry heat

GLASS BEADS STERILIZERHeat transfer device.Temp. 220˚CWarm up time:20 min

(Oliet et al,1958) Instruments such as

endo files and burs (10 sec)Grossman(1974)

recommended the use of salt media sterilization.

Sterilization by moist heat A)Temperature below 100ºC

Vaccine bath

Pasteurisation Fractional sterilisation

B)Temperature of 100ºCBoiling at 100˚C Steam at atmospheric pressure

at 100˚C

Tyndallisation

C)Temperature below 100ºCAUTOCLAVE :TYPES:1)Simple iron jacketed2)Low temp;low pressure type3)High pressure;high vacuum type PARAMETERS:I. pressure: 15 psiII. temperature: 121˚CIII. time: 15-20 min

MATERIALS STERILIZED:Dressing packs,surgical instruments,laboratory equipments,Pharmaceutical products…Liquids also can be sterilized by autoclave

AUTOCLAVE ……….

Principles of autoclaving:

1. Saturated steam heats the article to be

sterilised rapidly by releasing latent heat

which participates in bacterial killing.

2. Steam contracts in volume and enhances

penetration.

Sterilization control:1)Spores of bacillus stearothermophilus.

2)Chemical indicators such as Brown’

steriliser control tubes.3)Thermocouple.4)Autoclave tape.

Advantages• Rapid and effective • Effective for

sterilizing clothsurgical packs and

towel packs

Disadvantages• Items sensitive to

heat cannot be sterilized

• It tends to corrode carbon steel burs and instruments

AUTOCLAVE ……….

PACKAGING/WRAPPING INSTRUMENTS FOR AUTOCLAVING:

Instruments must be clean.

Packaging must be porousto permit steam to penetrate.

Wrap/bag is heat sealed/sealed with tape.

In case of storage after sterilization,autoclave cycle should end with a drying phase.

Moist Heat Dry Heat1. The moist heat have water and steam.

1. No use of water and steam.

2. Sterilization with coagulation of protein.

2. Sterilization with oxidation.

3. This process is under pressure.

3. This process is on direct flame.

4. Process takes less time.

4. Process takes more time.

5. Moist heat are Boiling & Autoclave.

5. Dry heat are Flame & Incineration.

Differences between dry heat and moist heat

DIFFERENCES BETWEEN DRY HEAT AND MOIST HEAT

STERILISATION BY FILTRATION:1)BACTERIOLOGICAL FILTERS

2)MEMBRANE FILTRATION

3)SAND FILTERS

Sterilisation by radiation

IONISATION RADIATIONSIncludes gamma rays,x-rays, accelerated electronsAct by formation of radiation tracks in the DNA of bacteria leading to its death.USES:•Rubber/plastic disposable goods,Surgical catgut,bone,tissue grafts…

NONIONISING RADIATION

NONIONIZING RADIATION

1)INFRARED RADIATION:-Form of hot air sterilization-employed for rapid mass sterilizationof syringes2)ULTRAVOILET RADIATION:-bactericidal action which acts byA) Denaturation of bacterial proteinsB) Damage of DNAC) Inhibition of DNA replication

GAS VAPOUR STERILISATION

1)Ethylene oxide2) Formaldehyde gas

3) Hydrogen peroxide vapours4)Others (CHLORINE DIOXIDE,PARACETIC ACID)

ETHYLENE OXIDE STERILISATION Is a gas at temp. <180˚CHighly penetrative ; noncorrosive with cidal action against bacteria,spores and viruses Destroys microorganism by alkylation and causes denaturation of nucleic acids Highly toxic, irritant,mutagenic,carcinogenicExcellent sterilizer of heat sensitive itemsIdeal for electric equipment , plastic goods , bone grafts , vaccines…

CHEMICAL VAPOUR STERILISATION/ CHEMI-CLAVECombination of dry saturated steam and formaldehyde to kill bacteria , spores,viruses.Formaldehyde acts by alkylation of nucleic acidsReq. combination of temp. and pressure are 127 -132˚C at 20-40 psi for 30min.

HYDROGEN PEROXIDE VAPOUR PLASMA

GAS STERRAD 100s

ULTRASONIC CLEANERS AND SOLUTIONSAn ultrasonic cleaner uses sound waves, that are

outside the human hearing range to form oscillating bubbles, a process called cavitation.

These bubbles act on debris to remove it from the instruments.

Ultrasonic cleaning is the safest and most efficient way to clean sharp instruments.

Operate the tank at one-half to three-fourths full of cleaning solution at all times- Use only cleaning solutions recommended by ultrasonic device manufacturers.

Operate the ultrasonic cleaner for 3-6 minutes for loose instruments 10-20 mins for cassettes or longer as directed by the manufacturer to give optimal cleaning.

HANDPIECE SURFACE CONTAMINATION CONTROL

ULTRASONIC SCALARS70% isopropyl alcohol Rinse cleaned inserts thoroughly in warm

water to remove all chemicals. As a final rinse, replace the insert into the scaler handpiece and operate the scaler for 10 seconds at the maximum water flow setting to flush out any retained chemicals

Dry inserts completely with air syringePackage in proper wrap, bags, pouches, trays,

or cassettes. Add spore tests and chemical indicators.

Ethylene Oxide is the preferred method of choice

Dry heat and chemical vapor methods of sterilization are considered ineffective methods with risk of damage to materials as per American Dental association Supplement to J.A.D.A. 8/92.

CLEANING OF INSTRUMENTS

CLEANING AGENTS

1)SOAPS :-Salts of fatty acids.-effective at pH >9

-Acts by reducing surface tension along the instrument surface

emulsification of contaminants which are removed in rinsing phase

2)DETERGENTS:-Synthetic compounds-some are bactericidal against specific gram +ve organisms. e.g. Na Lauryl sulphate is effective against strep. Pn.-reduce surface tension of instruments causing removal of contaminats.

3) OTHER FAT SOLVENTS SOLUTIONS:-such as acetone,ether,xylene

DISINFECTIONDisinfection refers to the destruction of pathogenic organisms (Ronald B Luftig)Destruction of pathogenic and other kinds of microorganisms by physical or chemical means. Disinfection is less lethal than sterilization, because it destroys the majority of recognized pathogenic microorganisms, but not necessarily all microbial forms (e.g., bacterial spores).

ASEPSIS: prevention of microbial contamination of living tissues or sterile materials by excluding, removing or killing microorganisms.

CHARACTERISTICS OF A GOOD CHEMICAL DISINFECTANT OR ANTISEPTIC:

1. Able to destroy a wide variety of microorganisms

2. Fast-acting short contact time3. Not affected by the presence of other

substances such as organic matter4. Non-toxic to human tissues as well as

non-corrosive and non-destructive to materials for which it is used

5. Should leave a residual antimicrobial film on the treated surface

6. Water-soluble and easy to apply7. Inexpensive and easy to prepare8. Stable under storage and shipping

conditions9. Odourless

High-level disinfection: inactivates vegetative bacteria, mycobacteria, fungi, and viruses but not necessarily high numbers of bacterial spores.

Intermediate-level disinfection:inactivates vegetative bacteria, the majority of fungi, mycobacteria, and the majority of viruses (particularly enveloped viruses) but not bacterial spores.

Low-level disinfectant: Liquid chemical germicide. OSHA requires low-level hospital disinfectants.

USE OF DISINFECTANT

METHODS OF DISINFECTION DISINFECTION BY CLEANING

DISINFECTION BY HEAT

DISINFECTION BY LOW TEMPERATURE STEAM

DISINFECTION BY BOILING WATER

DISINFECTION BY CHEMICAL AGENTS

COMPONENTS OF CHEMICAL DISINFECTANT

DAMAGE CELL MEMBRANE

A. Surface active agents – interact with the lipid in the cell membrane disrupt cell membrane

1. Cationic agents• Quaternary ammonium compounds• Cationic detergents widely used for skin

antisepsis• Effective at alkaline pH• Example: zephiran, benzalkonium

chloride2. Anionic agents• Remove dirt through the process of

emulsification• Effective at acidic pH• Example: soaps and detergents

B. Phenolic compounds – also denature proteins

1. Phenol • No longer used due to toxicity• Mainly used as gold standard in the evaluation of

new chemical agents using the phenol coefficient test

2. Cresols (Methylphenol)• Phenol derivatives• More potent and safer• Example: lysol

3. Hexachlorophene• Biphenol with six chlorine atoms• Used in germicidal soaps• With possible neurotoxicity

C. Alcohols – also denatures proteins

1. Ethanol• Bactericidal• Remove lipid from skin surface• Widely used to clean the skin before

immunization or venipuncture

2. Isopropyl alcohol• Greater bactericidal activity than

ethanol;• less volatile• Side effect: narcosis due to inhalation of

fumes

3. Benzyl alcohol – used as preservative

DENATURATION OF CELLULAR PROTEINS

1. Acids and alkali• Strong acids and alkali – bactericidal • Weak acids (benzoic, propionic, and citric

acids) – used as food preservatives

2. Alcohol and acetone

3. Phenol and cresol

MODIFY FUNCTIONAL GROUPS OF PROTEINS AND NUCLEIC ACIDS:

A. Heavy Metals – damage enzyme activity of bacteria by binding to sulfhydryl groups1. Mercurials• Example: thimesoral (merthiolate) &

merbromin (mercurochrome) skin antiseptics

2. Silver compounds• Bactericidal• 1% silver nitrate – ophthalmia

neonatorum (Crede’s prophylaxis)• Silver sulfadiazine – burn wounds

B. Halogens – oxidizing agents inactivate enzymes

1. Iodine• Inactivates sulfhydryl-containing enzymes• Also binds specifically to tyrosine residues

in proteins• Best antiseptic sporicidal, bactericidal,

fungicidal, viricidal, amoebicidal• Used prior to obtaining a blood culture

and installing IV catheters• Two forms:a) Tincture of iodine

2% iodine solution + potassium iodide in ethanol

Used to prepare skin prior to blood cultureb) Iodophors

Complexes of iodine with detergents (e.g. Betadine)

Used to prepare skin prior to surgery; less irritating

2. Chlorine• Kills by cross-linking essential sulfhydryl

groups in enzymes form inactive disulfide

• For water treatment• Hypochlorite (HOCl) – sanitize dairy &

food processing equipment; household disinfectant

3. Hydrogen peroxide (H2O2) • Wound cleansing; surgical devices and

soft plastic contact lenses• Effectiveness limited by the organism’s

ability to produce catalase• Attacks sulfhydryl groups

C. Alkylating agents

1. Formaldehyde• Sporicidal• Commercially available as FORMALIN (37%

solution in water)• Hydroxymethyl group of formaldehyde

causes alkylation of –NH2 and –OH groups of nucleic acids

• For preservation of specimens and preparation of vaccines

• Kill Mycobacterium tuberculosis in sputum and fungi in athlete’s foot

2. Glutaraldehyde• Sporicidal; with two reactive aldehyde

groups• 10X more effective than formaldehyde• Used as cold sterilant• Medical equipments like respiratory

therapy machines and other equipment that can be damaged by heat

3. Ethylene oxide• Sporicidal• Used in gaseous sterilization of heat-

sensitive materials or equipments like heart-lung machine and polyethylene tubes in anesthesia machines

• Potentially carcinogenic

OPERATING ROOM PROCEDURECeilings,walls and floors are

regularly disinfectedAccess to operation theatre and

recovery area is restricted to o.t personnel with special scrub dress.

Arms should be above waist when not operating.

O.t are disinfected by fumigation a)fumigators b) potassium permanganatefumigation is initiated after

setting up the instruments.fumigators is set for 30 min.

PARAMETERS :•Relative humidity : over 70%•Temperature : 30-40 ˚C•Formaldehyde level : 5 ppm/more

HAND SCRUB TECHNIQUE

1st step towards aseptic surgical technique.

Purpose of hand scrub is 2 fold:

1)remove superficial contaminants

2)reduce bacterial count on skin.

Scrubbing duration :10 min_Dunphey and Way(1973)

“WHO”

PREPARATION OF SURGICAL SITE• Before operation, wash surgical site,

surrounding area with soap, water; particularly wash debris from injuries

• Prepare skin with antiseptic solution; start in centre, move to periphery

• Chlorhexidine gluconate and iodine preferable to alcohol as less irritating to skin

• Solution should remain wet on skin for at least two minutes

“WHO”

DISINFECTION OF DENTAL UNIT AND ENVIRONMENTAL

SURFACES

HOSPITAL WASTE MANAGEMENT

1)GENERATION2)SEGREGATION3)COLLECTION4)STORAGE 5)TRANSPORTATION6)TREATMENT AND DISPOSAL

86

WASTE CATEGORY TYPE OF WASTE TREATMENT AND

DISPOSAL OPTION

Category No. 1Human Anatomical Waste (Human tissues, organs, body parts)

Incineration@ / deep burial*

Category No. 2

Animal Waste(Animal tissues, organs, body parts, carcasses, bleeding parts, fluid, blood and experimental animals used in research, waste generated by veterinary hospitals and colleges, discharge from hospitals, animal houses)

Incineration@ / deep burial*

Category No. 3

Microbiology & Biotechnology Waste (Wastes from laboratory cultures, stocks or specimen of live micro organisms or attenuated vaccines, human and animal cell cultures used in research and infectious agents from research and industrial laboratories, wastes from production of biologicals, toxins and devices used for transfer of cultures)

Local autoclaving/ microwaving / incineration@

CATEGORIES OF BIOMEDICAL WASTE

Category No. 4

Waste Sharps (Needles, syringes, scalpels, blades, glass, etc. that may cause puncture and cuts. This includes both used and unused sharps)

Disinfecting (chemical treatment@@ / autoclaving / microwaving

Category No. 5

Discarded Medicine and Cytotoxic drugs (Wastes comprising of outdated, contaminated and discarded medicines)

Incineration@ / destruction and drugs disposal in secured landfills

Category No. 6

Soiled Waste (Items contaminated with body fluids including cotton, dressings, soiled plaster casts, lines, bedding and other materials contaminated with blood.)

Incineration@ / autoclaving / microwaving

Category No. 7

Solid Waste (Waste generated from disposable items other than the waste sharps such as tubing, catheters, intravenous sets, etc.)

Disinfecting by chemical treatment@@ / autoclaving / microwaving

Category No. 8

Liquid Waste (Waste generated from the laboratory and washing, cleaning, house keeping and disinfecting activities)

Disinfecting by chemical treatment@@ and discharge into drains

Category No. 9

Incineration Ash (Ash from incineration of any biomedical waste)

Disposal in municipal landfill

Category No.10

Chemical Waste (Chemicals used in production of biologicals, chemicals used in disinfecting, as insecticides, etc.)

Chemical treatment @@ and discharge into drains for liquids and secured landfill for solids.

Infection control has helped to allay concerns of the health care personnel and instill confidence and in providing a safe environment for both patient and personnel.

REFERENCES Ayliffe GAJ et al (1993):chemical disinfection in hospitals Block SS(1983):disinfection,sterilisation and preservation Medical devices agency (1996):sterilisation,disinfection and cleaning of

medical equipment.. Neelima Malik ,textbook of oral and maxillofacial surgery,3rd edi. Textbook of microbiology by Chakravathy. Operative dentistry, infection control, 4th edition, sturdevent. Textbook of microbiology, sterilization and disinfection, 7th edition,

Ananthanarayan Textbook of clinical periodontology, Newman, Takei, Carranza, 11th edition. Sterilization and disinfection of dental instruments by ADA Disinfection & sterilization of dental instruments TB MED 266, 1995 CDC, guidelines for disinfection & sterilization in health care facilities

2008. Infection prevention and control, college of respiratory therapists Ontario,

june 2011 Effects of sterilization on periodontal instruments, JOP, vol 53, no:7, 1982. New CDC guidelines for selected infection control procedures, chris miller. CDC guidelines for infection control in dental health care settings, Dec19,

2003/vol.52. Sterilization of ultrasonic inserts.