Infection control in orthodontics
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Introduction • • • • • •
Introduction General concepts of infection control Diseases Strategies of infection control Infection control in orthodontics Conclusion www.indiandentalacademy.com
Introduction Mighty things from small beginnings grow ‌‌.Dryden
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Earth inhabited by all forms of life… Microscopic to Macroscopic Role of microbes • Important for maintaining food chain • Break down complex molecules in the soil & the digestive tract of man & animals
Microbes & Human Disease • Present everywhere • Useful & harmful www.indiandentalacademy.com
• Cross Infection : May be defined as the passing of harmful microorganisms from one place or person to another place or person
• Human body lives in harmony with many microorganisms • All are susceptible to sterilization but some are resistant to disinfection. www.indiandentalacademy.com
• Orthodontists have the second highest incidence of hepatitis B - Starnbach and Biddle 1980 • Dentists generally are considered to have a low risk for AIDS Klein RS, Phelan JA, Freeman K - 1988 ,NEJM.
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Factors for transmission of infection • Source of infection: – patients suffering from acute infection – patients in prodromal stage – carriers: known and unknown
• Means of transmission (MID) – Contact with saliva, blood or blood mixed with saliva may transmit pathogenic microbes – A certain minimum concentration of these microbes must be present in the blood or saliva to overcome the body’s defences this is known as the minimum infective dose www.indiandentalacademy.com
• Susceptible host – A person who lacks effective resistance to a particular pathogenic micro-organism. – Factors influencing • Heredity, nutritional status, medication such as steroids, chemotherapy, underlying diseases like diabetes, immunization status.
• Route of Transmission – Inoculation – Inhalation
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• Among dental staff – Risk of sero-conversion after needle stick injury -0.4% in HIV and 20% - 25% in HBV – existing lesions on the hands • HBV, Syphilis, HSV transmitted to operators’ ungloved hands from saliva or lesions in patients mouth & any break in the hand skin will then serve as the portal of entry for these pathogenic microbes
– dental aerosols - increased respiratory infc. – splashes of contaminated sharp material – contaminated instruments www.indiandentalacademy.com
Risk to patients due to: • Lesion on operators ungloved hand • Contaminated operators ungloved hand • Contaminated instruments and other dental equipment. www.indiandentalacademy.com
Infections of concern • • • •
Hepatitis B / C / D HSV I and HSV II HIV - AIDS and ARC Gonorrhea, syphilis, wound infection, abscesses, tetanus • Varicella, CMV, measles, influenza, rubella, tuberculosis, herpetic karatitis, herpetic whitlow www.indiandentalacademy.com
Infections to be wary of: • Hepatitis B: it is the major cause, worldwide, of acute and chronic hepatitis, hepatocellular carcinoma. – 200,000,000 carriers worldwide – heat resistant virus destroyed after 5 min in 95C. Virus difficult to kill and survives up to a week on contaminated surfaces and instruments. – Incidence 5 times more than in general population www.indiandentalacademy.com
Risk of infection • Ample evidence since 1960’s about the risk of transmission, more from patients to staff. • Due to immunization the risk is falling • 50% cannot give any history of illness • very small amounts of fluid (0.1um) sufficient for transmission • transmission can occur by percutaneous inoculation, via intact barriers, indirect transmission- the environment must be considered contaminated after treatment of an HBV positive patient, since HBV is very stable outside the body. www.indiandentalacademy.com
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• AIDS and HIV infection: – Dramatic increase in the no. of AIDS patients worldwide as well as visiting the dental clinic – Progress of infection: • virus may stimulate antibody production (2 to 12 weeks) • virus incorporated into neucleoprotein of T4 lymphocytes and may remain latent for years • virus can be activated to reproduce itself & infect more lymphocytes • virus depresses no. of T4 lymphocytes hence leading to depressed immunity - AIDS and ARC www.indiandentalacademy.com
• Risk of transmission: – low among dentists – virus found in most of body fluids but saliva has been shown to have a inhibitory effect. – Easily destroyed outside the body and normal disinfection and sterilization procedures are effective.
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Oral manifestations of HIV
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Objectives of infection control • To protect patient as well as dental staff • to reduce the numbers of pathogenic microorganism to the lowest level possible • to ensure high standards of infection control during treatment of every patient & to prevent transmission of infection • to simplify the cross infection control procedures with minimum inconvenience. www.indiandentalacademy.com
Definitions: • Sterilization: is the destruction of microorganisms including highly resistant bacterial and mycotic spores. • Disinfection: is the removal of some but not all microorganism. • Sanitation: reduction of microbial flora to safe public health levels
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Strategies in infection control
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• All patients must be screened • Members of the dental team must stay healthy – Immunization mandatory (OSHA-Occupational Safety and Health Administration) – Hand wash and hand care – Personal hygiene • Provide barriers for protection: gloves, mask, eye protection, clinical attire. • Organize instruments carefully: consider tray systems, packaging instruments and sterilization pouches. • Precise and careful aseptic technique www.indiandentalacademy.com
• Sterilize or disinfect all items and instruments used during dental procedures. • Minimize possible contamination from dental equipment. • Dispose contaminated wastes safely. • Understand local and national guidelines. • Careful laboratory asepsis
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Categories of Task, Work Areas, & Personnel • The OSHA guidelines evaluate & classify tasks undertaken in a dental practice into one of the three categories: • Category I • Category II • Category III www.indiandentalacademy.com
• Category I: – tasks that involve exposure to blood, body fluids, or tissues. – All procedures or other job related tasks that involve an inherent potential for contact of mucous membrane or skin with blood, body fluids, or tissues, or a potential for spills or splashes of these. – Most tasks performed by the dentist, oral hygienist, chair side assistant and laboratory technician would fall into this category. www.indiandentalacademy.com
• Category II: – tasks that involve no exposure to blood, body fluids or tissues, but personnel carrying out these tasks may be required to perform unplanned Category I tasks. – Tasks performed by clerical or non-professional workers who may, as part of their duties, help to clean up the office, handle instruments or impression materials, or send out dental materials to laboratories, would be classified as Category II. www.indiandentalacademy.com
• Category III: – tasks that involve no exposure to blood, body fluids or tissues. – A front-office receptionist, book-keeper, or insurance clerk who does not handle dental instruments or materials would be a Category III worker.
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Patient Screening: people to watch out for • High risk of hepatitis B: – – – – – – – – – –
intravenous drug abusers, homosexual and bisexual males, persons working and living in institutions, people in developing countries, patients with acute and chronic liver disease, history of jaundice, recipients of unscreened blood, health care personel, oncology and dialysis patients, infants born to HBV positive mothers www.indiandentalacademy.com
• High risk for HIV infection: – – – – –
homosexual and bisexual males intravenous drug users transfusion recipients infants born to infected mothers hetrosexual contacts of infected persons
• Immunosuppresed individuals: – – – –
neonates, old age patients on cytotoxic drugs and antimetabolite agents diabetes mellitus, rheumatoid arthritis leukemia, radiotherapy.
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Immunization: personnel who should be immunized • • • • •
Dentists Hygienists Dental surgery assistants Laboratory technicians Engineers who repair dental equipment
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For what? • • • • • • • • •
Hepatitis B Influenza Mumps Measles Tetanus Rubella Poliomyelitis Whooping cough Tuberculosis www.indiandentalacademy.com
Vaccination procedure - Hepatitis B – Recombivax HB : the 1st recombinant-DNA vaccine – Engerix B : the latest recombinant-DNA vaccine • Pretesting: need not be given to individuals with anti - HB level over 100iu/l • Immunization: – first dose - elected date – one month later – 6 months after the first dose • For more rapid immunization using recombinant vaccine, the 3rd dose may be given 2 months after the initial dose, with a booster at 12 www.indiandentalacademy.com months .
• Post vaccination screening: – screening for antibody response is carried out 2- 4 months after last injection ( never later than 6 months after the last injection) – non responders should be given three more doses of vaccine
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• Booster doses: duration of immunity not precisely known and may vary between 3-5 years, generally booster doses given after this period • also an be given if antibody titer is seen to fall below 100iu/l. • in some countries this is determined by the post vaccination serum levels i.e. – If anti HB levels are below 100iu/l then revaccinate within 6 months. – If anti HB levels are between 101 - 1000iu/l then test after 2 - 4 years – If anti HB levels are above 100oiu/l then test after 4-6 years. www.indiandentalacademy.com
• During pregnancy: CDC states: “Although there is no risk to the fetus if the vaccine is given, it is not routinely recommended, and therefore always consult the dental health care workers physician.â€?
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Hand Care • The surface of hand contains both transient and resident microorganisms • hand washing removes blood debris and microorganisms but may damage the skin, esp. soaps • Correct hand washing should maintain the pH balance of the skin www.indiandentalacademy.com
• Many soaps have a min pH of 9 & such alkalinity alters the surface pH & results in skin roughness & redness. • Hand washes should , therefore , be based on detergents with pH similar to that of the skin • Antibacterial hand wash such as Chlorhexidine 4% may cause dry sore hands if used too many times. •
If gloves are not worn, hands become contaminated with blood during dental procedures. Remnants of blood have been found under the nails of the thumbs and index fingers of 80% of dentists, and 40% had blood on their hands after the weekend.
• Physical damage to the hands / skin can occur during activities outside work www.indiandentalacademy.com
A Few Principles • Change to different product if hand wash disinfectant cause irritation. • Remove all rings and jewelry before washing as irritants may accumulate under these. • Use cool water for rinsing • Dry hands thoroughly after rinsing • Change gloves periodically to avoid build up of sweat • Keep fingernails short and manicured. www.indiandentalacademy.com
• Use a good quality moisturizing cream regularly after each clinical session • Protect cuts or abrasions on the hands and forearms with a water proof dressing. • Dental personal who have exudative dermatitis refrain from all direct patient care.
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Hand washing • • • •
Rubbing removes microorganisms form the skin Lathering holds them suspended away from the skin Rinsing washes them off Disinfection action of hand washing will remove insitu microorganisms • Hand washing before gloving is intended to remove transient microorganisms and to suppress residual micro-flora while wearing the gloves. • Hand washing after removal of gloves is intended to remove micro-organisms which may have penetrated the gloves through microscopic defects or tears . www.indiandentalacademy.com
Surgical hand scrubs • These are preparations that significantly reduce the number of micro-organisms present on intact skin. A surgical hand scrub should : – Act fast – Not irritate the skin after repeated use – Have a broad range of bactericidal and residual activity – surgical hand scrub and health care personnel hand wash. www.indiandentalacademy.com
Antiseptics used in hand wash • Chlorhexidine 2-4% with 4% isopropyl alcohol in a detergent solution with a pH of 5-6.5. studies indicate it to be more effective than povidone iodine or PCMX • Povidine iodine 7.5 -10% • Phenolic compounds – Hexachlorophenol : directly absorbed into blood stream thru intact skin, could be toxic if conc rises. – Parachlorometexylenol (PCMX) is bactericidal and fungicidal at 2% conc. • Alcohols: Ethyl alcohol and isopropyl alcohol potent bactericidal effect at 70% conc. www.indiandentalacademy.com
Hand Washing Procedure
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• Personal Hygiene : • Hair should be short or kept away from the face • Facial hair should be covered with a face mask or shield • Jewellery should not be worn on the hands or arms during clinical sessions • Nails must be kept clean & short.
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Personal protection • • • •
Gloves Masks Protective eye wear & Protective uniforms
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Gloves • The main types of gloves used in dentistry : – – – –
Latex gloves - sterile and non sterile vinyl gloves - sterile and non sterile general purpose utility gloves surgeons sterile gloves
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Why Gloves • Hands are the major source of cross infection • occult blood under the nails have potential to infect patients and staff members for up to 5 days, even after repeated hand washing Allen, Organ (1982) • cuts and abrasion on the hands and skin can act as a portal for infecting as well as getting infected, in Hepatitis patients a cut can contain 100million viruses/mm www.indiandentalacademy.com
How to select gloves • Gloves manufactured by double dip process with less irritating catalyzing coagulants. These gloves have less pinholes than single dip gloves • Powdered using cornstarch or cetylpyridium chloride. Talcum powder is a mineral material , which may cause irritation, & is not recommended. • if allergy noted stick to hypoallergenic gloves containing low level of diethycarbamates and no thiurams. www.indiandentalacademy.com
• Repeated use of one pair of gloves after use is not advisable for the following reasons : – Exposure to disinfectants used to wash gloves after use causes defects and permeability in gloves. – Chemicals used in routine dentistry damage gloves, e. g. Eugenol, Copalite varnish. – Prolonged use of gloves increases hand perspiration, which causes skin irritation. – There is an increase in glove permeability to bacteria after use and bacteria multiply beneath the glove material. www.indiandentalacademy.com
• Double gloving and over gloving are acceptable procedure in cases of high risk patients and in patients who are medically compromised, or when the operator has dermatological conditions of the hand skin. • Be careful near flames and while mixing addition silicone
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• Many latex gloves contain accelerators such as dithiocarbamate products. Compounds of dithiocarbamate may inhibit the platinum catalyst in polyvinylsiloxane impression putty. When putty is mixed while wearing certain brands of latex gloves, the set of the putty is inhibited, or the bulk of the putty may set, but the surface remains tacky. •
Over-glove with vinyl gloves when mixing such materials. www.indiandentalacademy.com
Orthodontists gloves • Risk of glove puncture is high in orthodontists • gloves that are relatively puncture resistant - has greater puncture resistance, greater thickness in the palm, a high stress area for ligature placement, thinner material at the finger tips - Aladan and Champag gloves meet these criteria – Cooley, McCourt and Barnwell 1989
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Masks • Protect from aerosols and splatter • Infections likely to be transmitted through aerosols include influenza, common cold or other respiratory diseases • One of the primary factors determining the mask life is the rate at which aerosolized material soaks through (wicking) www.indiandentalacademy.com
• When choosing a face mask, note the following : – It has Bacterial filtration efficiency of 95% – Does not contact nostrils or lips – High filtration for small particles as well as breathability – Close fit around the entire periphery – Does not cause fogging of eyeglasses – All masks can be worn for max. one hour www.indiandentalacademy.com
Points to remember • Essential to wear mask when – using aerosol producing instruments, – washing instruments, – disinfecting surfaces – using lathe • use new surgical mask for each patient • if mask becomes wet replace immediately • do not touch or adjust the mask during procedure • don’t let it hang around the neck www.indiandentalacademy.com
• A new mask that is available in the UK (Fluidshield), has an inner protective filter, which provides the mask with a BFE of 99% and resists penetration of contaminated fluids which collect on the outer mask layer. This mask also has an enclosed nosepiece, which is made of malleable aluminium and can be adapted to facial contours . This prevents 'fogging' of face shields or protective glasses. www.indiandentalacademy.com
The nose piece of the Fluidshield mask
Eye Protection • Sharp particles projected with speed from the eyes • blood/ saliva may enter operators eyes and hence transmit infection • injuries to eye of patients by sharp instruments esp. in supine position
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• Protective clothing • Should be made from synthetic material, with high collars & a minimum of seams, buttons or buckles. • Should be changed at least daily or when visibly contaminated • CDC & ADA recommend long-sleeved uniforms. Tuck the bottoms of the sleeves into the gloves (protect the lower arms) • Head covers recommended during invasive dental procedures
• Additional precautions – – – – –
pre treatment tooth brushing chlorhexidine mouthwash high volume aspiration rubber dams efficient air filtration and ventilation www.indiandentalacademy.com
Avoiding injuries • Point sharp end of instrument away from hand, syringes away from anyone. • Avoid handling large number of sharp instruments at a time • avoid hand contacting rotating instruments • dispose off sharps immediately after use • wear heavy utility gloves during clean up
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What if injured • Maintain a written log for recording injuries, including exposures to blood • Wash the injured site with soap & water, do not scrub. Encourage the wound to bleed, but do not suck • If eyes are exposed , flush them with plain water • The risk from the injury should be evaluated & lab tests & vaccinations done www.indiandentalacademy.com
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Limiting spread of fluids (aseptic technique) • Remove and use only necessary items, plan in advance. Use unit dose material. • Restriction zones : areas to which contaminated items & instruments used for a dental procedure are confined • If instruments have to be take from drawer use overglove or tissue • preload mouthwash cups with a mouthwash tablet • locate clinical notes and x ray viewer outside the operatory. • One way flow www.indiandentalacademy.com
Covering surfaces – Surfaces likely to be contaminated can be covered while they are still clean – use clear plastic wrap, aluminium foil, paper with impervious backing, commercial available polyethylene sheets & tubings
• The decision whether to cover or disinfect is determined by four factors : • The likelihood of the surface becoming contaminated • The cost of disposable covering • The time saved • Damage to equipment & surfaces by disinfection www.indiandentalacademy.com
Disinfecting surfaces • ADA recommended; – sodium hypochlorite 5.25% - 10 min (1:10) – Iododphor 10min - (1: 213) – combination synthetic phenolics - 10 min(1:32) (note: no glutaraldehyde and alcohol recommended bcoz they cause denaturing & precipitation of proteins)
• other authorities have shown denatured ethyl alcohol 70% to be effective with synthetic phenols (Lysol) www.indiandentalacademy.com
• Author’s recommendations: – Alcohol can be used on small surfaces that need quick drying between patients – large areas can use water based disinfectants which ultimately become cheaper.
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Disinfectants used • Formaldehyde - these solutions are not recommended for routine use in dentistry • Glutaraldehyde -2% recommended for immersion of instruments. Undiluted solution can cause irritation to the eyes and skin and hence contact should be avoided. • Glutaraldehyde - phenate solutions - used for high level disinfection and sterilization (1:16 dilution), sporicidal against aerobic and anaerobic spores, vegetative bacteria, hydrophilic and lypophilic viruses. It remains active for 30 days. www.indiandentalacademy.com
• Chlorine preparation: sodium hypochlorite solution 5% is commonly used. Solution has to be prepared on a day to day basis and pre-cleaning is essential. Usually used on surfaces. Contact avoided as it tend to corrode metals, esp. aluminium. • Chlorous acid and chlorine dioxide: generated by a combination of sodium chlorite and an organic acid provide high level disinfection in 3 min. May cause oxidation of metals & mucous membrane sensitivity www.indiandentalacademy.com
• Combination of phenolics: phenylphenol and benzyl chlorophenol. Bactericidal, virucidal fungicidal but not sporicidal, damage plastic and rubber • Iodophors: weak complexes of iodine with a carrier that increases the solubility of iodine and provides a slow release. Used as surface and immersion disinfectants, and effective against wide variety of microorganisms but not sterilization. Discoloration of certain surface. Generally safe to contact. • Quarternary ammonium compounds & alcohols not recommended either as surface or immersion disinfectant www.indiandentalacademy.com
Instrument management • Store instruments in instrument trays • do not overload trays so as to allow free circulation of steam. • Store trays such that longest stored trays are taken out first. • Use IMS cassettes with indicator strips • sterilization pouches for single instruments and handpiece. www.indiandentalacademy.com
Sterilization of instruments • Pre-cleaning disinfection using holding solution.(a synthetic phenolic solution, diluted 1:32, is an ideal holding solution) • Pre - sterilization cleaning • Sterilization • Aseptic storage
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Sterilization • Steam autoclave – unwrappped items 132 (30lb/in2) 3min 121 (15lb/in2) 15min – lightly wrapped items 8 min 20min – heavily wrapped items 10min 20min www.indiandentalacademy.com
Directions for use • Do not overload trays • load trays carefully to allow free circulation of steam • use trays with perforated bases or lids • separate packed or wrapped items • remove all large particles before placements • rinse disinfectants and cleaners from the instruments before placement. www.indiandentalacademy.com
• Used for high quality stainless steel, hand-pieces, cloth goods, glass slab, dishes stones. Large plastic suction tips, heat resistant plastic instruments • Carbon steel instruments will rust, instruments must be lubricated and 2% sodium nitrite can be used to prevent rust • STATIM autoclave can be used for rapid sterilization of instruments www.indiandentalacademy.com
Chemical vapour sterilizers • Operate by heating deodorized alcohol, formaldehyde and etylmethyl ketone solution, to 132C at 20-40lb/in2 for 20 min in a closed chamber
• advantages: – short cycle - 30min, short flash cycles of 7 min available now – instruments do not rust, dull or corrode – instruments are dry at the end of the cycle.
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• Main disadvantage being the presence of residual vapour that can be removed by a chemipurge system. • Instruments must be clean and dry • use recommended pouches • do not wrap in heavy cloth and paper • the formaldehyde exposure in accordance with OSHA should be 1ppm for 8 hrs or 2ppm of 15 min. www.indiandentalacademy.com
Dry heat sterilizers • Unwrapped moderate loads of instruments can be sterilized at 160-170C in 1hr. • Not recommended for busy practice: – low temperature pockets in the chamber may prevent sterilization – complete sterilization cycle takes long time and if chamber opened in between then loads are not sterile – handpieces get damages at high temperatures of 160C www.indiandentalacademy.com
In Orthodontics • Impressions: – immersion preferred to spraying – through rinsing before and after disinfection – recommended disinfectants include: • • • •
chlorine compounds, iodophors, combination synthetic phenolics glutaraldehyde www.indiandentalacademy.com
For alginate •
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Choice of product is very important and preferably to use manufacture recommended disinfectant. – Rinse the impression thoroughly under running water and shake impression to remove excess water – dip in 1:10 hypochlorite for several seconds – wrap the impression in gauze soaked in hypochlorite and and leave in plastic bag for 10 min. – remove impression and rinse thoroughly alginate impregnated with disinfectants are also available but the tray part still remains infected www.indiandentalacademy.com
Precautions in lab • • • • • •
A receiving area present technicians should be vaccinated frequent hand washing and changing of gowns do not eat in lab sterilize burs and stone separate instruments and environment for materials that have been inserted into the mouth • disinfect out going cases www.indiandentalacademy.com
• Instruments: – instruments have large hinge areas that are difficult to clean and sterilize – sharp edges may be come dull esp. After repeated autoclaving, though less damage in chrome plated instruments – lubrication of hinges should be carried out with 1% sodium nitrate before sterilizartion to prevent rust – chemical vapor sterilization and convection heat very popular – careful when cleaning with ultrasonic esp. pin and ligature cutters www.indiandentalacademy.com
– Contaminated bands, arch wires and brackets may be sterilized in band cassettes using rapid heat, steam and chemical vapor. – Alternatively they may be immersed in 2% glutraldehyde overnight
– unused chain and elastomeric ligatures placed in boxes and removed with sterilized tweezers. www.indiandentalacademy.com
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The other side • Is it all necessary?? – Hepatitis B associated with dentistry since 1960s – no official AIDS case reported in dental clinic except a Florida dentist – dentists generally are at a lower risk of AIDS (NEJM)
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Conclusion Adequate infection control measures are needed not just for the safety of the dentist but for the patient too. Inedequate cross infection measures can also be a legal problem & invite litigation from the patient as well as the regulatory bodies www.indiandentalacademy.com
Thank you www.indiandentalacademy.com Leader in continuing dental education
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