Quality Assurance

Reprinted from Denturist Association of Canada

INFECTION CONTROL

OVERVIEW

Infection Control in the Denturist Office is a necessary yet sometimes difficult goal. In view of the potentially life-threatening consequences of disease transmission, infection control deserves the utmost serious consideration and effort on the part of the practitioner. This document will attempt to simplify and clarify the procedures necessary to minimize the potential for cross-contamination in the Denturist clinic.

For the purposes of this guideline, infection control will be broken down into the following areas:

• Occupational Health
• Patient Evaluation
• Instrument/Equipment Cleaning, Disinfection and Sterilization
• Surface Cleaning and Disinfection
• Laboratory Asepsis and Aseptic Techniques

The aim of infection control is to:

1. Reduce the number of pathogenic microbes to a level where the normal resistance mechanisms of the body can prevent infection;
2. Break the chain of infection and eliminate cross-contamination;
3. Treat every patient and instrument as though capable of transmitting infectious diseases; and
4. Protect patients and staff from infection and its consequences.

Infection Control Protocol is determined by the procedure, not by the patient. Universal precautions should be used routinely with every patient, regardless of the perception of the patient's potential “threat”. It is the ethical and legal responsibility of the Denturist to ensure that all reasonable precautions have been taken to protect the safety and health of all involved.

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OCCUPATIONAL HEALTH ISSUES

Personal protection covers a broad area in infection control, from immunization to barrier use. Use the following guidelines to minimize the risk to yourself, your staff, your family and your patients.

A. VACCINATION

Several vaccines are routinely administered during childhood and adolescence. Some of them require updating (boosters).
i. Rubella (R)	ii. Hepatitis B	iii. Influenza	iv. Mumps (M)
v. Measles (M)	vi. Tetanus (T)	vii. Diptheria (D)
If in doubt about your vaccination status, talk to your physician. He/she may recommend either testing you for antibodies or having a booster. Boosters are generally not required after MMR immunization. Td booster is needed every 10 years. Influenza vaccine is given yearly in October. Current recommendations are that the hepatitis B vaccination does not require boosters after the initial series of vaccines is given.

B. HAND WASHING

In order to reduce the likelihood of cross-contamination, hand washing facilities should be designed to minimize hand contact with inanimate objects such as water tap handles and soap dispensers. Faucets with foot controls, sensors, or any other method of water dispensing which does not require manual contact help avoid the possibility of contaminating taps.

HANDS SHOULD BE WASHED:

1.  at the beginning of each day
2.  prior to gloving
3.  after the removal of gloves
4.  if a glove is torn or punctured
5.  when hands come in contact with an object or surface which may be contaminated; and
6.  whenever coming back to work after a break.

Single use disposable towels should be used to dry the hands. Regular liquid soap is appropriate for the procedures of a Denturist practice. Antimicrobial soap is necessary for surgical procedures only.

C. GLOVES

Gloves must be worn when hand contact with bodily fluid or mucous membranes is anticipated, or when touching surfaces that may be contaminated. A latex, non-sterile glove is recommended for most non-invasive dental procedures. A well-fitting, comfortable glove which does not tear easily is recommended. Non-sterile latex, vinyl or other impervious material are acceptable alternatives.

Hands should be washed prior to gloving and must be washed after removal of gloves. Do not wash gloves with hand soap or use gloves after they have been in contact with disinfectants, as their effectiveness is diminished by exposure to chemicals. Remove and discard gloves after each and every patient. Gloves cannot be effectively disinfected and should not be re-used.

Practitioners are encouraged to try different brands to assess the comfort, strength, cost and irritability of a glove. Hypoallergenic gloves are available. Any health care worker who has exudative lesions or weeping dermatitis on their hands should refrain from all direct patient care and from handling patient-care equipment until the condition resolves. Some problems related to the wearing of gloves can be reduced by wearing the gloves only when required, changing the gloves frequently, or by using vinyl, nylon, or cotton gloves as a “liner”.

Gloves should not be worn when handling charts, radiographs or telephones. Always remove and replace gloves before performing these activities. When cleaning the operatory between patients or using chemical disinfectants, utility gloves should be used.

Washing hands and donning a new pair of gloves in the presence of the patient at the beginning of each procedure will assure him or her that infection control procedures are being used in your clinic. Promote your practice by using infection control procedures.

D. MASKS

Routine use of masks is not necessary; rather, they should be donned for procedures in which splashing or spattering of blood or other body fluids is likely. However, due to the close proximity of the Denturist to the patient's oral cavity, many patients and Denturists feel more secure when a mask is used. Disposable masks serve as a filter and a barrier to splashes and splatter of fluids. Masks lose effectiveness if moist. In addition, as they become contaminated during any procedure, they should be replaced for each patient. When removing your mask, handle it by the strings only, to prevent potential contamination of your hands.

An important feature of a mask is its fit. It has been estimated that approximately 20% of air breathed passes around the mask and is unfiltered. Purchase masks that fit snugly against the face and meet the minimum standard of 95% filtration of particles 5 microns or smaller.

E. EYE PROTECTION

As with masks, eye protection is necessary only if splashing or spattering are likely. Protective eye wear prevents infection (such as by the viral infections influenza and hepatitis B) from being transmitted by spattering of the conjunctiva of the eye, by saliva, or other body fluids. Protective eye wear or prescription glasses fitted with side-shields usually offer sufficient frontal and side splash protection for the Denturist in the clinical setting.

Eye wear should be cleaned between patients. To clean glasses, wear gloves and wash the glasses under running water and dry thoroughly. Check with the individual manufacturer to see which, if any, disinfectant can be used on the glasses.

F. LAB COATS AND CLINIC JACKETS

Clinic coats and jackets should be worn only at the office and should not be worn to and from work, or outside of the office during the day. Both short sleeved and long sleeved jackets offer benefits. Short sleeves allow the arms of the Denturist to be washed if they should come in contact with a contaminated item. Long sleeved jackets offer protection against injury to the Denturist's arms. As both sleeve lengths offer benefits, the selection is up to the personal requirements of the wearer. Polyester-cotton blends or a tight cotton weave launder well and can be washed in hot water. Jackets should be changed daily and when they become visibly soiled. Washing clinic clothing in a normal laundry cycle is sufficient.

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PATIENT EVALUATION

It is important that the Denturist use a comprehensive health questionnaire to identify medical problems which, in conjunction with denture therapy, adversely affect the patient. Denturists must, however, be aware that patients may have no symptoms from many infections which can be transmitted in the Denturist's office. This is particularly true of hepatitis B, hepatitis C and HIV infection. The majority of patients with these infections do not know themselves that they are infected, and thus cannot tell their Denturist.

Relying on information provided by the patient to assess infectious disease risk is not advisable. All patients must be treated safely in order to protect both the Denturist and patient.

Occasionally, patients can give “socially convenient” answers to medical questions. Untruthful replies to medical inquiries can be intentional, but the vast majority are unintentional. Language difficulties or sheer ignorance can prevent a patient from understanding the meaning or intention of a question. In a recent study of 377 confirmed hepatitis B carriers, only 80 persons (21%) reported on their dental medical questionnaire that they had been exposed to hepatitis.

Only about one-third of hepatitis cases present with the clinical manifestations of severe illness and jaundice, leaving two-thirds of persons having had hepatitis unknowingly. These persons cannot inform the Denturist of a past history of hepatitis that they may have assumed was merely a bout of influenza. These same people are unable to accurately report their carrier status.

Infection control practice is the best way to protect your patients and yourself against infection and to protect yourself against litigation.

Follow a written infection control protocol and use the same infection control procedures for every patient.

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INSTRUMENT & CLEANING AND STERILIZATION

Infection control techniques based upon the current knowledge of disease transmission demand that all instruments and devices used in and around the oral cavity should either be sterilized or subjected to high level disinfection. Nearly all instruments that are used in a Denturist practice are classified as “semi-critical” (those items that contact but do not penetrate the oral mucous) or as “non-critical” (items or surfaces that are touched during treatment but are not directly in contact with the oral mucosa). Semi-critical items require a minimum high level disinfection, not necessarily sterilization.

Discussion on this topic requires that terms be defined:

Sterilization refers to the killing of all life forms.

Disinfection is the destruction of some –but not all– micro-organisms, and varies from a low level (when only minimally resistant organisms are destroyed) to a high level (when all but very resistant organisms are destroyed).

Cleaning is the removal of visible debris, blood and saliva from an instrument, reducing the number of – but not all micro-organisms.

In the practice of Denturism, there are four methods of sterilization which are recognized as acceptable techniques. Each method has distinct advantages, disadvantages and applications. No single method of sterilization is suitable for all items or materials, therefore, a combination of methods is required. The acceptable methods of sterilization are:

1. Water Vapor under pressure – AUTOCLAVE
2. Chemical Vapor under pressure – CHEMICLAVE
3. Dry Heat – DRY HEAT OVEN
4. Chemical – CHEMICAL STERILANTS

All recommended methods except for chemical sterilants allow for biological monitoring to ensure that the sterilization process is effective. Biological monitoring is critical; “colour change” indicators on packaging do not indicate or guarantee sterility. Each sterilization procedure is tested using a different spore tester and it is imperative that the appropriate product be used to test sterilization equipment. A written record of the monitoring results should be kept. Chemical sterilants must be properly mixed and maintained at the recommended temperature for the recommended length of time to be effective. There is no way to monitor a chemical sterilant; therefore, it is the least desirable method of sterilization. If chemical sterilants are to be used, the frequency with which solutions are used and changed must be monitored and documented.

NO INSTRUMENT OR ITEM CAN BE EFFECTIVELY STERILIZED UNLESS IT IS THOROUGHLY CLEANED FIRST.

The most effective method of cleaning an item prior to sterilization is ultrasonic cleansing. Ultrasonic cleansing is preferred to hand scrubbing because it is 16 times more efficient and it significantly reduces the potential for the splashing of contaminants during scrubbing. Utility gloves should be worn when hand scrubbing instruments.

After cleaning, instruments can be rinsed, dried and visually inspected for debris. If the item is still dirty, it will be necessary to hand scrub it. Once clean, the items are placed into sterilization bags and sealed. Bags must have either a chemical indicator on the paper side or have a piece of indicating tape placed on the bag to verify that it has been exposed to the sterilizing cycle. Staples or paper clips should not be used to close the bags, as they do not provide a seal.

YOUR STERILIZATION TECHNIQUES ARE ONLY AS GOOD AS YOUR CLEANING AND PACKAGING.

Heat has been recognized as the most reliable method of dental instrument sterilization and should therefore be used for all instruments and items that can withstand repeated exposure to high temperatures. Only when an item cannot withstand steam, chemical vapor or dry heat sterilization should it be sterilized using a chemical sterilant. It is recommended that GLUTARALDEHYDE be used as a chemical sterilant. Choose a product which is 3.2% Alkaline, 2% alkaline or 2% Acidic and totally immerse the cleaned item for a minimum of 10 hours at the manufacturer's recommended temperature. Use of a chemical sterilant should be followed by aseptic rinsing with sterile water, drying, and, if the instrument is not used immediately, placement in a sterile container. Occupational Health and Safety issues dictate a need for adequate ventilation.

Attention must be paid to the use-life of a product, as it can be affected by the number of loads of items sterilized in a particular batch of solution. Consult the product label and package insert to verify the active ingredients of a product and the instructions for use. Non-critical items which have not had direct contact with the mucosa can be disinfected using an approved high-level disinfectant solution.

Adapted from Accepted Dental Therapeutics, Dentist's Desk Reference Materials, Instruments and Equipment and Merchant V. Prosthodontics & infection control Oral Health, Nov 1989, Vol 79, No. 11.

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SURFACE CLEANING AND DISINFECTION

The need for surface cleaning can be reduced somewhat by the use of “barriers” and disposable items. Any surface that can be covered and will be in contact with the Denturist's hands or the patient's head should be covered. Whenever possible, foot controls should be used to operate taps and chairs. Plastic wrap or disposable covers having an impermeable plastic layer should be used to cover head rests, light handles, light control switches, and manual chair switches.

Surface cleaning and disinfection should take place after treatment of each patient and at the completion of daily work activities. Acceptable surface disinfectants must have documented evidence of bactericidal, tuberculocidal and virucidal activity. Products whose labels state only “hospital-level disinfectant” are not acceptable for use in a Denturist office. Check the label and product enclosure to ensure that a disinfectant will kill Staphylococcus aureus, Salmonella cholernesuis & Pseudomonas aeruginosa. The disinfectant must be tuberculocidal and must be effective on both lipophilic viruses (e.g. HIV) and hydrophilic viruses (e.g. Polio and Coxsackie) in 10 minutes or less.

Just as it is important to clean an instrument before it is sterilized, it is equally important to clean a surface before it is disinfected. As all disinfectants are inactivated by protein and blood, surfaces should be cleaned before they are disinfected. For surfaces which are not obviously dirty or contaminated, the “spray-wipe-spray” technique is adequate. A disinfectant is first sprayed on and the damp surface wiped with a paper towel to remove any debris (the cleaning stage), then disinfectant is sprayed on again as the disinfectant step. This spray is left on to allow for time for disinfection.

Chlorine products, iodophore products and complex phenolics are all good disinfectants. All three of these products have disadvantages which are listed below:

• Chlorines - corrosive; damages clothes, plastic, rubber, metal and steel. Usually must be prepared daily
• Iodophores - stains (removable), must be prepared daily
• Synthetic phenols - film accumulation, damages plastics and rubber
• In addition, 6% hydrogen peroxide and 70% isopropyl alcohol are adequate disinfectants. Hydrogen peroxide may corrode certain metals.

Water-based products in a pump spray/squirt bottle are preferable to alcohol-based or aerosol products. Alcohol makes the proteins in blood and saliva more difficult to remove from a surface and tends to evaporate quickly, thus reducing the contact time on the contaminated surface. Because alcohol makes the proteins in blood and saliva more difficult to remove, alcohol or alcohol based solutions should not be used for the first spray and clean phase, or to clean any obviously contaminated surfaces.

Sodium hypochlorite (household bleach) can be used in a 1:10 to a 1:100 dilution, depending on the amount of organic matter (blood and mucous) present on the surface to be disinfected. A fresh mix of sodium hypochlorite must be made daily (every 24 hours). Spray the disinfectant onto the surface to be cleaned, not onto disposable towel.

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ASEPTIC TECHNIQUE & LABORATORY ASEPSIS

Impressions and prostheses should be rinsed under gently running tap water to remove excess blood and saliva. All items that have been used intraorally (wax rims etc.) must be disinfected by immersion or by using the “spray-wipe-spray” technique. Stone casts must be immersed in hypochlorite or an iodophore. Dentures and impressions should be immersed in a disinfecting solution for the time recommended for TB disinfection. After the necessary immersion time has elapsed (check product directions) it is necessary to rinse the impression under running tap water to remove any residual disinfectant.

The following table can be used as a guide when selecting disinfecting solutions for impressions and prostheses:

Note: Solutions must be prepared according to the manufacturer's recommendations for surface disinfection or immersion in disinfection. Sodium Hypochlorite diluted 1:10.

Warning: Materials vary in their response to chemicals. If damage or distortion occurs, shorten the immersion time or spray the impression, wrap in a paper towel and store in a sealed plastic bag.

Adapted from: Merchant V. Prosthodontics and infection control, Oral Health, November 1989. Vol. 79 No. 11 and Palenik C. & Miller C., Laboratory ascpsis: Disinfection of impression materials and microbially soiled dental prostheses. Quintessence of Dental Technology. 1990/1991.

Any instruments or materials to be used on new uncontaminated prostheses should be kept and used separately from those to be used with prostheses that have already been inserted in the mouth. Any laboratory equipment such as a bur which has come into contact with a denture that is being adjusted, repaired, or relined or otherwise altered must be cleaned and sterilized after each patient denture case using the method recommended on page 7 of this document. Exercise caution to ensure that no damage occurs to the prosthesis during the disinfection procedure.

Use an approved disinfectant solution (iodophore or sodium hypochlorite) in place of water in the pumice pan. It is advisable to have two pumice pans, one for use on new prostheses and the other for contaminated prostheses. If a single pumice pan is used on all dentures, the pumice must be changed after each case. If a separate pan is used for new prostheses only, that pumice should be changed daily.

Use only rag wheels which are autoclavable/sterilizable. Soak brushes and other non-sterilizable, non-disposable items overnight in an approved disinfecting solution such as glutaraldehyde, iodophore, complex phenolic or sodium hypochlorite. Some rag wheels can be autoclaved and should be sterilized when possible.

Countertops must be kept clean throughout the day and must be disinfected frequently, at minimum, at the end of each day. Clean and disinfect around sinks and taps daily. Clean and disinfect work pans each time a case is completed.

Any items that are being sent to a laboratory should be disinfected and packaged before it leaves the clinic. Any item returning from a laboratory should be disinfected immediately upon arrival.