Cleaning and Disinfection of Surfaces: By No Means Superficial

The surfaces of the dental clinic are particularly high-risk areas as a large number of germs can settle there in a short amount of time. In the vicinity of the treatment area, contamination can occur through aerosol or contact transmission; in other parts of the practice, the pathogens can spread through the movement of wind or dust or with the help of clothing or shoes. A surface disinfection must not only be effective but must also be quick and in no way damaging to the surface material. For every type of surface, there is an optimal disinfectant, which must be applied with the proper disinfection techniques.

The treatment room, check-in area, waiting room, hallway, and office all contain a multitude of surfaces that must be cleaned and disinfected. Disinfecting does not differ from cleaning in terms of the degree of cleanliness but rather by the quantitative reduction of germs. Even if a surface is not 100 percent germ-free, it may still be considered to no longer present a danger of infection. Which surfaces must be cleaned and which surfaces must be disinfected is based on the distance to all possible infection sources. At the same time, the care and maintenance of the treated object also play a decisive role.

Clean from the Start

A wet, dust-binding cleaning that mechanically removes all visible contaminations is an absolute must in every dental clinic. To this end, cleaning agents that contain detergents composed of a long-chain nonpolar hydrophobic side and a polar hydrophilic side are used. Both the surface tension between the cleaning agent and the contamination and the surface tension of the water itself are reduced so that the adhering particles can be dissolved and absorbed by the water. Cleaning agents with detergents help eliminate partial populations of pathogenic microorganisms. However, this method does not ensure a sufficient germ reduction.

Disinfectants for Surfaces

Using fast-acting surface disinfectants with a short contact time of under two minutes is especially important for disinfection between patient treatments. These substances, which must absolutely be effective against HIV, Hepatitis B and C, and tuberculosis, are available as either alcohol-based disinfectants or quaternary ammonium compounds. Alcohol-based disinfectants are usually not used for the disinfection of large surfaces such as floors, due to their high flammability, higher costs, as well as to avoid the formation of alcoholic aerosol caused by its high volatility.

The Requirements from Surface Disinfectants are:

1. As wide a spectrum as possible (at least against bacteria, fungi, tuberculosis, and non-enveloped viruses)
2. Quick effectiveness at low concentrations
3. Ability to completely coat a surface
4. Non-damaging to materials
5. Absence of aldehydes and phenols
6. As neutral an odor as possible
7. Additional cleaning power through surface-active agents
8. Residue-free drying leaving behind no streaks or smears
9. Resistance to light and air
10. Adequate shelf life, during which the disinfectant does not decompose or lose its effectiveness
11. High cost effectiveness
12. No negative environmental effects

For the disinfection of surfaces, one has the choice between finished solutions or concentrated products, from which one develops diluted solutions. In order for a disinfection to be successful, it is absolutely necessary to comply with the concentration-time ratios as instructed by the manufacturer. For ready-made wet wipes, the information regarding the effective spectrum and contact time refers to the disinfectant agent contained in the wipes in its undiluted form. The same applies for ready-made products for spray disinfection. They are sold in bottles with a spray mechanism that is sometimes operated with propellant gas.

Around the Dental Chair: Patient-near Surfaces

Everything within a radius of two meters from the dental chair must be considered contaminated by an aerosol. All surfaces within this radius are considered “near to patient” and must thus be disinfected after the treatment of every patient. In small treatment rooms, this area might be the entire room; in larger treatments rooms, the “near to patient” area can be marked with colored tape.

The fewer objects and surfaces there are within the two-meter radius, the easier and quicker the disinfection is. Thus, the simple rule of thumb is to simply remove every unnecessary object from this area. All instruments and materials should only be in potentially exposed areas during treatment.

Measurements have shown that 70 percent of aerosols are prevalent within a proximity of 60  cm. This focal area requires maximum attention. Affected objects include the swivel tray and all objects that are on the tray. Furthermore, objects such as medical-technical devices, spittoon, lights and light handles, fixtures, and the treatment chair are at risk of infection by the dentist and dental personnel themselves.

Surfaces Near to Patient and Far from Patient

 Wipe Disinfection for Smaller Surfaces

The best method to reduce the number of germs on a surface is the wipe disinfection. A spray disinfection does not guarantee a comprehensive coating of the surface and can thus result in gaps of effectiveness. Spray disinfection is also not an adequate substitution due to the harmful aerosol it produces – it should only be used as a supplemental measure.

All stationary objects that cannot be disassembled should be externally disinfected using wipes. Two important aspects of the disinfection are the complete coating of the surface with ample disinfectant and adhering to the recommended exposure time. Flat surfaces should be completely coated, while hoses, coupling, and tubes of the suction unit should only be coated on handles. Hard-to-reach surfaces have to be additionally treated with a spray disinfection.

For sensitive materials such as the treatment chair, there are substances that can both disinfect and at the same time treat and nourish – they should be applied at regular intervals. The cover of the dental chair, more or less the “business card” of the dental clinic, will not get damaged by this disinfection treatment and become porous or cracked. This nourishing treatment helps to avoid a difficult disinfection or having to prematurely replace the article.

For personal safety, gloves should be worn during a wipe disinfection; during a spray disinfection, gloves as well as a dental mask should be worn.

Spray and Wipe Disinfections

 Ready-made Wet Wipes: Practical and Economical

A quick and thrifty alternative to wipe disinfection with soaked disposable towels are ready-to-use wet wipes, which are sold in practical dispenser boxes. The advantages of these towels are many:

• They can be used immediately.
• The amount of liquid is exactly measured; the wipes are thus extremely economical. The only thing that needs to be observed when using these wipes is that the surface is visibly moist. If necessary, the wipes can be remoistened.
• The disinfection can be completed with only one hand.
• One wipe (depending on its size) can disinfect surfaces up to 8m2 – highly economical (review instructions of manufacturer).
• The empty dispenser box can be refilled with refill packs. This is cost effective and helps the environment by reusing rather than disposing.

Cleaning and Disinfection of Floors: From the Ground Up

Official opinions differ regarding the cleaning and disinfection of the floors. The Robert Koch institute recommends a simple daily wet cleaning of all floors without the use of disinfectants. Others argue that in order to properly protect against infection, the treatment floor must be disinfected at the end of every workday and the other floors on a weekly basis. Visible contamination such as blood, pus, or other infectious secretions must be immediately removed. In such a case, the contamination is removed with tissue paper soaked in disinfectant solution; after elimination of the contamination, a wipe disinfection should be conducted.

Disinfection Techniques for Floors

The standard technique for the preparation of floors was the two-pail technique for a long time. The mop first soaks up the disinfectant from one pail. After wiping the floor, the mop is pressed out over a second pail before it is again dipped in the first pail. This technique helps prevent the accumulation of contamination in the disinfectant, which could possibly have a deactivating effect.

The most commonly used procedure today is the two-mop method. The disinfectant is applied with one mop and then wiped clean with a second mop that absorbs the excessive moisture. Two mops are required for each room.
New techniques make it possible to achieve the same effect at a considerably lower investment of materials and time. The specially constructed “floor wiper” has an integrated detachable tank that directly sprays the surface with disinfectant. A lever on the handle of the wiper provides a simple control of the spraying.
For cleaning the floors, certain safety measures are necessary such as wearing gloves and ensuring ample ventilation in the room.

Avoid Mistakes: Make Your Work Easier

Mistakes that are made in connection with disinfectants and cleaning agents often jeopardize the success of the disinfection. By starting off with the proper knowledge, one can optimize and make easier the implementation of the preparation measures:

• The success of the disinfection is dependent of the characteristics of the surface itself. Even when purchasing materials, furniture, and devices, it is important to pay attention to whether or not the surfaces are flat, resistant to disinfectants, and can be easily wiped. It should also have as few hard-to-reach areas as possible.
• Sensitive materials (such as seat cushions, keyboards, and lamp protective glass) should be tested for tolerance to disinfection.
• Disinfectants may not be mixed with cleaning agents in an attempt to save time by cleaning and disinfecting simultaneously. This may, however, only be done when the manufacturer specifically recommends such a mixing. Otherwise, there is the danger of a chemical interaction that will either reduce effectiveness or completely deactivate the disinfectant. Other possible reactions between the two agents include the accumulation of residue on the surfaces that is difficult to dissolve or the formation of toxic vapors.
• There can also be negative interactions between the active agents of various disinfectants. When changing disinfectants, be sure to rinse carefully with water first.
• Only suitable active agents may be used. Agents that work reliably in other areas of the practice cannot be used for surface disinfection due to toxic, allergenic, or corrosive characteristics. The only substances to be used are those that were conceived especially for this purpose and are marked with the green color coding.

For a Successful Surface Disinfection

Disinfectants are not susceptible to increased pathogenic resistance over time. Hence, swapping of products is gratuitous. If the disinfectant does not perform as specified, there are other possible causes:

• The product is not registered in accordance with the Medical Device Directive and does not have a CE marking with a number – this is a sign of low quality.
• The effective spectrum has gaps, e.g. for low concentrations of alcohol-based disinfectants or quaternary ammonia compounds.
  Ready-made solutions were prepared with the wrong concentration. It makes sense to use dosage spoons or type-tested disinfectant dosage devices.
• Ready-made solutions act too quickly for their concentration. The choice of a fast-acting agent is very important for the short time period between patients.
• The disinfection does not comprehensively coat the surface or the surface is not completely covered. At-risk areas include corners, vents, flanges, tubes, pumps, membranes, and gaskets.
• The disinfectant should not be used after its expiration date and must be stored in closed containers.
• Some substances, such as oxygen peroxide, have a limited shelf life after the solution has been applied. At some point, the instability will cause a loss of effectiveness.