Infection control in the dental office
- Introduction :
Hygiene and asepsis have now taken a prominent place in all medical disciplines and are at the heart of our society’s concerns.
In order to ensure the quality and safety of patients and healthcare personnel, dental practitioners must know and apply strict hygiene methods in each act performed daily.
- General information:
1/ Why talk about hygiene in the dental office?
Increased risks of contamination due to:
- High number of patients
- Confined spaces
- Acts generating bleeding and contact with saliva
- Aerosols produced by rotating instruments
Potential consequences:
- Transmission of infectious diseases to patients and staff
- Cross-contamination between patients
- Main infectious diseases that can be contracted in the dental office :
- Nasopharyngeal disorders
- Skin conditions
- Viral diseases (measles, rubella, mumps, etc.)
- Blood-borne diseases (hepatitis B and C, HIV, etc.)
- Tuberculosis
- Flu
- Pneumonias…
- Sources of contamination:
- Hands: vector of contamination
- Instruments and equipment (control buttons, surfaces, headrest, etc.)
- Clothes
- Spittoon and aspirator; the dirtiest items in the dental office
- Air spray from turbines and contra-angles, septic aerosol
- X-ray films
- Asepsis and antisepsis :
− Asepsis:
A set of techniques designed to prevent the introduction of germs into the body. Asepsis is achieved through antisepsis and sterilization.
− Antisepsis :
Set of processes used to combat septic germs, destroy them and prevent their proliferation (antisepsis is synonymous with disinfection)
- Dental office :
To minimize the risk of transmission, the architectural organization of the dental practice must allow for the adaptation of a systematic method of hygiene and asepsis control.
It is necessary to establish a “one-way” circulation, not only for the patient, but also for medical devices:
− Patient: must follow a simple and precise circuit from entering the office until leaving.
− Instruments:
Sterile instruments are stored near the dental unit. After use, the circuit of soiled instruments must be short, and once decontaminated, they are taken to the sterilization room.
The patient must not cross the path of the instrumentation, as the sterilization room is not accessible to him.
This double circulation is not always ideally possible without crossing, but the strict routing of the instrumentation must be favored.
– The dental unit:
Selection criteria to ensure optimal hygiene:
- Smooth, seamless seat and backrest, easily removable upholstery
- Smooth unit surfaces, without sharp edges
- Smooth cords for dynamic instruments
- Smooth spittoon and removable suction system for easy disinfectant cleaning
- Easy-to-clean treatment tablet, removable if possible
- Foot pedal control, allowing activation of the chair, dynamic instrumentation and programming.
− Protection of the dental team:
- The outfit must be short-sleeved, closed at the neck, without pockets;
- Change of clothes every day, and every time it is soiled;
- Storage in a specific location;
- The outfit must be perfectly washable at high temperatures.
- Objectives : Elimination of soiling, and reduction of transient flora.
Indications:
− At the start and end of the shift;
− On visibly dirty, wet or powdered hands;
− Before and/or after everyday activities.
- Rules to follow:
− Duration, 40 to 60 s
− Forearms free;
− No jewelry;
– Short nails, without varnish;
– Gentle brushing, limited to the nails.
- Description of the procedure :
These are 6 steps, each to be repeated 1 or 2 times before moving on to the next step:
- Palm to palm;
- Right palm on back of left hand and left palm on back of right hand;
- Palm to palm, fingers interlaced;
- Back of fingers against opposite palm with fingers interlocked;
- Circular friction of the right thumb embedded in the left palm and vice versa
- Rotating friction in back and forth motion and the joined fingers of the right hand in the left palm and vice versa;
- Dab dry using disposable hand towels.
Gloves should be worn after the mask and goggles.
Latex gloves must be changed after 30 minutes, as the barrier effect is no longer guaranteed beyond that.
− Vaccination :
− Dental practice staff exposed to the risk of contamination are required to be vaccinated. Vaccination protects staff by ensuring individual protection and prevents contamination of patients being treated.
− Mandatory vaccinations: Diphtheria, Tetanus, Poliomyelitis, Hepatitis, Tuberculosis.
− Recommended vaccinations: flu, whooping cough, rubella, measles and chickenpox.
- Sterilization chain :
- Pre-disinfection: (decontamination)
- Definition :
“This is the first treatment to be carried out on soiled equipment and objects in order to reduce the population of microorganisms and facilitate subsequent cleaning.”
NB: the pre-disinfection solution must therefore have:
– a cleaning function
– an antimicrobial function
- Goals :
− Protect staff from any contamination
− Improve sterilization steps, reducing initial contamination
− Facilitate the cleaning of medical devices
- Procedure :
− Preparing the bath
– Total immersion of the instruments
− After soaking time: wash.
- Cleaning:
- Definition :
“Consists of removing dirt and stains from surfaces or objects without damaging them, with the aim of presenting a state of cleanliness that can be checked with the naked eye.”
Mechanical cleaning therefore follows chemical cleaning with detergent-disinfectant. It allows a greater number of microorganisms to be eliminated.
- Conditions for good cleaning :
– Chemical action of products dissolving stains
– Mechanical action which consists of rubbing to remove dirt
– Heat action promoting cleaning
− Cleaning time.
- Cleaning methods:
- Manual cleaning:
Instruments soaked in a warm bath containing detergent or disinfectant-detergent.
Cleaned using a soft brush. Then the instruments are rinsed for 5 minutes and then dried thoroughly.
− Disadvantages: risk of contamination
- Staff, bites and cuts
- For the environment; nebulization when brushing.
- Ultrasonic cleaning:
Very suitable for instruments with complex structures (endodontic instruments, burs, striated instruments)
− Instruments completely immersed in a bath where ultrasound is maintained for 4 – 15 minutes
– Rinsed for 5 minutes then dried completely.
- Automatic cleaning: By washing machine:
- “Wetting” rinsing phase corresponding to pre-cleaning
- Hot wash phase: detergent + high temperature
- Rinse phase
- Disinfection:
- Definition :
“It is an operation with a temporary result, making it possible to eliminate or kill microorganisms and/or inactivate unwanted viruses carried on contaminated inert environments depending on the desired objectives.”
[inert media: soils, surfaces, instruments, air, water, etc. …]
- Procedures:
Disinfection only applies to heat-sensitive objects; any instrument that can withstand heat is sterilized.
- Cold chemical disinfection:
Disinfection will be carried out on clean equipment. The instrumentation will therefore have been pre-disinfected, rinsed, cleaned and rinsed.
The most widely used product is glutaraldehyde, which has a very broad spectrum of activity covering bacteria, molds, viruses, and spore-forming forms.
– Operating mode:
− Immerse the clean object for 30 minutes (follow the manufacturer’s recommendations)
− Rinse in water corresponding to the desired level of disinfection.
- Hot disinfection:
- Disinfection by thermo-disinfector
- Disinfection by water vapor disinfector.
- Rotary instruments:
Handpieces, contra-angles, and turbines must be pre-disinfected, cleaned, lubricated, and sterilized after each treatment.
− Pre-disinfection and manual cleaning:
− Clean the external surface using a wipe soaked in a decontaminating solution
− Rotating instruments in place, evacuate water from the pipes for 30 seconds
− Remove the bur, disconnect the rotary instrument
− Send a cleaning spray, lubricant
− Replace the cutter, replace the rotary instrument on the cords
− Run for 30 seconds to remove excess lubricant
− Remove the bur, disconnect the rotary instrument
− Wipe the external face of excess lubricant
− Wipe the optical fiber with a cotton ball soaked in alcohol.
- Packaging:
Ensures that the device remains sterile over time.
Packaging must:
– Allow the action of the sterilizing agent, without being degraded
– Ensure that the contents remain sterile
− Preserve the properties of medical devices
− Allow the collection and use of sterilized objects under aseptic conditions.
Packaging methods:
– Rigid packaging
− Folded packaging
– Heat-sealed packaging
- Sterilization:
- Definition :
“It is the implementation of a set of methods and means aimed at eliminating all living microorganisms of any nature, whether carried by a perfectly cleaned object.”
- Aim :
– This is an operation allowing a reduction in the number of micro-organisms by 10 6 .
– The preservation of the state of sterility over time.
“ We only sterilize what is clean.”
- Procedure :
− The Class B 13060 saturated steam autoclave is the only reference process in the medical field. The sterilizing agent is saturated steam at a temperature above 100°C, therefore under pressure.
− It must be routinely set to obtain a temperature and a sterilization tray of 134°C for a duration of at least 18 min.
− The water in the autoclave must be free from impurities.
− The sterilizer indicator light displays the different cycles offered by the sterilizer, the different tests, as well as certain information concerning the water level, certain alarms, etc.
− It is imperative to consult the instructions supplied with the device. They indicate the different sterilization phases:
– the different pre-vacuums
– the rise in temperature
– the temperature drop
- Loading the autoclave:
− The load consists of all the packaging placed in the sterilizer tank;
– This load must be placed in the autoclave enclosure in such a way as to ensure good steam penetration and avoid the risk of water retention by overloading the tank, for this:
- objects must not protrude from the tray or touch the walls of the autoclave;
- avoid any contact between the load on the lower tray and the bottom of the upper tray
- place the bags against each other vertically, transparent side against transparent and paper side against paper side
- Do not stack bags on trays.
- Do not press the trays against each other to allow the water vapor to circulate
- Unloading the autoclave:
− The bags must be dry when they come out of the sterilizer
- Sterilization control:
− The final check of the sterile state of the product is linked firstly to the Routine Checks of the autoclave in order to ensure that it is working efficiently and secondly to the tests of the effectiveness of the sterilization process.
- Checking the correct functioning of the autoclave using
− routine tests:
- The vacuum test : this test is intended to check for the absence of air or leaks in the autoclave, because an air leak constitutes an obstacle to the penetration of steam.
– This test is carried out cold before any sterilization, it is also noted on the autoclave indicator and indicated on a recording sheet.
- The Bowie-Dick Test
– This test aims to verify the penetration of water vapor into the heart of the porous load:
– This is a fundamental test to assess the presence or absence of an air pocket.
− It must be carried out daily, at the start of the working day, alone, while hot. The test is a standard package already wrapped which will be placed in the center of the tank to be treated according to a specific cycle with a 3.5 min plateau at 134°C.
− This cycle is noted on the sterilizer indicator light. The test pack includes a sheet coated with a chemical indicator which turns on contact with steam at 134°C.
− The test is acceptable if the sheet has turned uniformly.
− A faulty test requires stopping the device and carrying out a technical check.
- The Helix test
− It is used to test the autoclave’s ability to sterilize hollow objects.
- Process efficiency test:
− Physicochemical indicators in the form of strips, they will be placed in a bag in the center of the load to be sterilized. They change color if the 3 fundamental parameters of sterilization are reached: pressure/temperature/time.
– Load control at the end of the cycle
Check :
– The quality of drying;
– The absence of perforation of the packaging;
− Changing the color of the crossing indicators;
− (heat-sensitive ink) on adhesives or bags, according to the manufacturer’s instructions;
− The turning of the physicochemical integrator placed in an individual sachet in the center of the load;
− The recording diagram (or ticket), obtained by a printer connected to the autoclave which gives the following information: Temperature, pressure, time;
− If all these conditions are met, if all the parameters converge.
- Prevention in dental care settings:
The principle is to apply strict hygiene rules:
– Hand washing
– Wearing gloves, masks, and headgear
− Use as much single-use equipment as possible (scalpels, needles, etc.)
– Decontaminate, clean, disinfect, sterilize
− Maintain sterile equipment in conditioners
” These are rules that apply to all patients .”
In front of a patient with a known potential infectious risk (AIDS, Hbs, Tb,
– Act scheduled for the end of the day
− Use as much disposable material as possible ( tray , mirror, probe, tweezers, etc.)
− Double protection: gloves, bib, disposable gown, etc.
− After treatment, disinfect the entire room and sterilize all instruments
− Place waste from the bags in separate, lined bags marked “Contaminant”
In case of accidental injury :
- Make the wound bleed and wash it under running water (30 secs)
- Immerse the injured area in Dakin or bleach
- Dry and compress the wound with sterile gauze
- Have a blood test performed for serological analysis
- Report the accident to occupational health.
CONCLUSION :
Sterilization of medical devices plays an important role in the fight against infection in the dental office.
But given the diversity of our practice, the challenge seems insurmountable and only rational organization, constant vigilance and renewed knowledge are able to bring comfort and peace of mind to practitioners.
Bibliography:
- ADF, Dental Practice Installation Guide. Regulatory Aspects and Advice. ADF; 2007.
- Australian Dental Association. Guidelines for infection control. ADA; 2012.
- Bassigny, F. (1988). The asepsis chain in the orthodontic practice. Revue d’Orthopédie Dento-Faciale, 22(3), 337-373.
- Kumar S, Atray D Pawai G, Balasubramanyam G, Duraiswamy P, Kulkarni S. Dental unit waterlines: source of contamination and cross-infection. Journal of Hospital Infection 2010;74:99–111.
- Recommendations for infection control during dental care. Brussels: Superior Health Council; 2011.
- Salah, AN, Al-Otaibi, MB, Al-dhmashi, ASF, & Mariee, AA (2024). Infection control practices and approaches in the dentistry field; a review. Journal of Bioscience and Applied Research, 10(1), 42-58.
- Ling, M.L., Ching, P., Cheng, J., Lang, L., Liberali, S., Poon, P., … & Sim, C. (2023). APSIC dental infection prevention and control (IPC) guidelines. Antimicrobial Resistance & Infection Control, 12(1), 53.
Infection control in the dental office
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