Disinfection and sterilization methods in dentistry: processing of instruments

The safety of the patient depends on the quality of processing of medical instruments. That is why sterilization in dentistry is given increased attention in every dental office.

The task of the medical staff is to comply with all stages of the processing of dental instruments, which allows you to be sure that that someone else's blood or saliva residues will not cause infection with dangerous diseases, including hepatitis, HIV, soft tissue diseases, etc. etc.

Sterilization types

Sterilization is the complete destruction of all microorganisms, which is a measure of absolute protection of the patient and the doctor during manipulations related to the treatment of teeth and oral cavity.

All objects and devices that come into contact with the mucous membranes of the oral cavity and the patient's blood are subject to mandatory processing to remove bacteria and microorganisms. It:

• instruments (canal filler, drilbor, boron other);
• dishes (flasks, beakers);
• dressings;
• rubber products used for dental procedures;
• other devices.

Today, several types of effective sterilization are used - steam and air. Each technique has its own purpose and features. In addition, they are used in working with the tool and glasperlen sterilizers, the disinfecting medium of which are glass balls heated to a certain temperature. The disadvantage of this technique is that the tools after processing must be used immediately. They are not subject to storage.

Steam

This type of sterilization is thermal. High temperature steam is supplied at a certain pressure. Both the temperature and the strength of the steam supply depend on the type of tool being processed. The main advantage of the technique is that steam is able to penetrate to the maximum depth, qualitatively cleaning the instrument and overalls from microorganisms. The method is used to process dental mirrors, disinfection handpieces, burs, cutters, abrasive heads.

Products made of metal, glass and textiles are disinfected at 132 degrees for 20 minutes. Steam supply force - 2 kgf / cm². For latex, rubber and polymer, use a gentle mode. Processing is carried out at a temperature of 120 degrees with a steam pressure of 1.2 kgf / cm². The duration of the procedure is 45 minutes.

Among the disadvantages of the method is the fact that processing can cause corrosion, including tools made of corrosion-resistant alloys. Condensation inevitably moisturizes the processed products, which affects the shelf life of instruments and increases the risk of contamination.

Autoclave for sterilization

Air

Sterilization with hot and dry air is one of the most effective and efficient methods of killing microorganisms, including resistant spores.

Instruments are processed at 160-180 degrees for 30-120 minutes. The duration of processing and the temperature in the chamber depend on the type of material and is determined by the documentation attached to the instruments and sterilizer.

The technique also has disadvantages:

• the active agent does not always evenly heat the product, which can lead to ineffective processing;
• some instruments are capable of deformation; only cold sterilization and disinfection are permissible for them;
• not all packing materials are suitable for dry heat.

Dry oven

Storage of sterile instruments

Instruments processed by any method of disinfection remain sterile only for a certain time, namely:

• sterilization in special filters - 20 days;
• disinfection in boxes without the use of filters - 3 days;
• processing in moisture-proof parchment or soft cloth packaging made of a double layer of coarse calico - 3 days.

Items sterilized by the air and steam method can also be stored in open trays on the so-called "sterile table". Such a table is laid only for 1 shift (6 hours) with the obligatory fixation of the time of covering. Storage is possible in UV germicidal chambers, for example, "Ultralight" with a transparent lid. The Ultralight treatment extends the sterility of the instrument up to 7 days by preventing contamination of the sterile items inside.

Preparation of instruments for storage is carried out under conditions of complete sterility. The medical staff should be in a gown and mask, and gloves should be worn on the hands of the person working with the tool. The instruments are taken from the table with forceps or tweezers, which must also be stored in sterile containers under a layer of a sterile diaper. The pick-up devices must be replaced every 1.5 hours.

Steps for precise and complete sterilization:

• mechanical cleaning of external surfaces from dirt and residues of biomaterials;
• pre-sterilization treatment (disinfection);
• packing in special bags;
• direct sterilization of the instrument in a steam autoclave or air sterilizer;
• fixing the time and date of sterilization;
• storage under certain conditions for a permissible time.

For some tools, this algorithm of actions is incomplete. For example, the processing of handpieces in dentistry according to SanPiN includes disassembly and lubrication of the instrument after mechanical cleaning. Only then are the handpieces packed and sent for sterilization.

Disinfection in dentistry

Anything that cannot be sterilized must be disinfected. All surfaces and objects in the dental office are treated. In this case, not all bacteria and microorganisms can be destroyed, but only their critical part. Instruments used for intervention in purulent foci, medical devices used during operations or injections are subject to compulsory disinfection. Only after that the instrumentation is sterilized to eliminate the slightest residues that can become causative agents of diseases or infections.

Water lines, which get dirty during the working day, are also disinfected. The processing of spittoons and other items used for examination and treatment is carried out after each patient, at the end and at the beginning of the work shift.

There are several methods of disinfection: mechanical, physical, ultraviolet, chemical. Each of them has its own characteristics.

Mechanical method

The essence of the mechanical method is to remove microflora from instruments, but not to eliminate microorganisms. Such disinfection is stage 1 before further processing, allowing to reduce the contamination of surfaces by microorganisms. Special designs, vacuum cleaners, running water are used as tools.

Some tools are resistant to mechanical stress, so special devices are used to pre-clean them. For example, boron processing begins with an ultrasonic cleaner that acts as a microscopic brush.

Physical method

Physical disinfectants are environmentally friendly and effective against microorganisms.

Disinfection is carried out after physical cleaning in three ways:

• boiling in distilled water (15-30 minutes);
• steam treatment in disinfecting chambers or sterilizers - 20 minutes at a temperature of 110 degrees under a pressure of 0.5 kgf / cm²;
• disinfection in a dry heat oven at a temperature of 120 degrees (45 minutes).

High-temperature exposure is an effective disinfection technique. To work with a dental instrument, air-type sterilizers are used (GP-80, GP-40, GP-20). The technique is attractive because of the low cost of the equipment.

Ultraviolet method

UV sterilizer for handpieces

Bactericidal radiation effectively suppresses many types of microorganisms.

The technique is used to disinfect water, work tables and cabinets, walls, ceilings and other objects in the room.

Ultraviolet installations are mandatory for use in areas with a high risk of spreading pathogens of various infections.

Wall-mounted, ceiling-mounted, mobile, recirculating and shielded irradiators provide effective disinfection, but only in the case when the treated surfaces and the air are dust-free and if the lamp is changed exactly at the time indicated by the working documentation. Otherwise, pathogenic bacteria adapt to UV treatment and stop responding to it.

Chemical methods

In every dental office, chemical disinfection or cold sterilization methods are used without fail in the form of:

• tablets;
• powders;
• granules;
• liquid concentrates;
• gases;
• ready-made forms (working solutions, aerosols, napkins, paints, varnishes).

Among the most used means for chemical disinfection are:

1. Hydrogen peroxide solution (6%). Optimal solution for glass disinfection, corrosion-resistant metals, polymer rubber. Products and tools are placed in the solution for 360 minutes at a temperature of 18 degrees or for 180 minutes if the solution is preheated to 50 degrees. Disinfected items can be stored for up to 7 days in a dark place, after which the peroxide is checked for the concentration of the active substance and it can be reused.
2. Acetic acid solution (1%) (Deoxone-1). The principle of disinfection is similar to the principle of working with peroxide. But the solution can only be reused within 24 hours.
3. Vapors of formaldehyde in ethyl alcohol (40%). For this technique, you will need additional equipment - a micro-anaerostat or a Minutka pressure cooker. Instrumentation (plastic, rubber, metal, glass) is packed in two layers of polyethylene (0.06-0.2 mm) or other packaging material and sent to the working chamber, the temperature in which should be 80 degrees. Items are disinfected from 120 to 180 minutes, depending on the material. Instruments packed in polyethylene remain sterile for 5 years. Disinfection in other packaging allows you to use items for 20 days. With this technique, degassing is required before using the instrumentation.

Disinfection and sterilization in dentistry will be incomplete without a mandatory check of the quality of disinfection. For this, the following tests are carried out - benzidine, orthotoluidine, phenolphthalein. In the first two cases, the remaining blood stains the reagent green. Phenolphthalein test allows you to identify residues of detergents by staining the reagent in a pink shade.

Sterilization and disinfection in dentistry, video:

Hygienic requirements for organizing and carrying out disinfection measures in the dental office

Complex medical procedures, which include dental procedures, require perfect cleanliness and sterility in the room. All surfaces are thoroughly washed and disinfected, taking into account the current sanitary standards and requirements.

Mandatory are 3 types of cleaning in the doctor's office:

1. Preliminary, carried out before each work shift. At this time, dust is removed from surfaces (floors, walls, furniture, equipment) by means of wet cleaning using disinfectants.
2. Routine cleaning is carried out throughout the day at least twice per shift. After admission of each patient, measures are taken to disinfect the critical and semi-critical zones.
3. General cleaning is done weekly.

The quality of work of the cleaning staff is checked by a responsible person, for example, a head nurse. Both instrumental and organoleptic techniques are used to control purity. The preparation of a flow chart that determines the actions of employees and relates to maintaining cleanliness at an optimal level is a must for every dental clinic.

Only compliance with all conditions of disinfection and sterilization makes a trip to the dentist safe. Therefore, it is worth trusting the treatment of your teeth to clinics that can guarantee the safety of the patient and provide him with documentation confirming the cleanliness of the instrument and the room as a whole.