Infection Control While Using Microscope Dental Loupes

In the post covid-19 era, dentists who treat patients using aerosoloziation are at an extremely dangerous risk of inoculation of themselves, their dental assistants and other office staff members and reinolculation of patients.

AEROSOLS AND AEROSOL DIFFERENTIATION

Aerosols are differentiated based on particle size: spatter (> 50 µm), droplet (≤ 50 µm), and droplet nuclei (≤ 10 µm). In dental settings, 90% of the aerosols produced are extremely small (< 5 µm). Spatter, being the larger particle, will fall until it contacts other objects (e.g., floor, countertop, sink, bracket, table, computer, patient or operator). Droplets remain suspended in the air until they evaporate, leaving droplet nuclei that contain bacteria related to respiratory infections. Droplet nuclei can contaminate surfaces in a range of three feet and may remain airborne for 30 minutes to two hours.If inhaled, the droplet nuclei can penetrate deep into the respiratory system. Furthermore, the susceptibility of developing an infection is influenced by virulence, dose and pathogenicity of the microorganisms, along with the host’s immune response.
Oral biofilm is resistant to antibiotics, antimicrobial agents and the body’s immune system; therefore, removal of bacteria in dental biofilms is best achieved by physical disruption — yet this very process contributes to aerosol production. Aerosols, both visible and invisible, are created during surgical and nonsurgical procedures that may include extractions, crown preparations, caries restorations, periodontal therapies, prophylaxes and endodontic treatment. Aerosols consist of water, saliva, blood, debris and microorganisms (e.g., bacteria, fungi, viruses and protozoa), along with their metabolites, such as lipopolysaccharides/endotoxins and other toxins.
The risks of dental aerosols can be reduced with the use of high-velocity air evacuation and preprocedural antimicrobial mouthrinses, as well as by flushing waterlines at the beginning of the workday and between each patient, wearing personal protective equipment (PPE), and using air purifications systems.Ultraviolet germicidal irradiation units,are all successful aids in minimising the aerosols.
Pre procedural rinses,air and water line precautions,use of personal protective equipment,ventilation management with air cleaning systems — such as high-efficiency particulate air (HEPA) filters, gas filter cartridges and electrostatic filters
The surface of the equipments put to use during the dental treatment would also require to be wiped to achieve disinfection by physical disruption.the same would also be required to be applied to microscopes and loupes.¹
Both the operative microscope and headlamp/ loupes have been found to contribute to microbial shedding. Care should be taken to assure proper cleaning, storage, and draping of these tools and, knowing that some shedding inevitably occurs.²

USE OF LOUPES

One obstacle faced when working with magnification is cross-contamination. Operators who use loupe must avoid touching or changing its orientation during treatment. The assistant may help to reposition the loupe or head strap if required. The use of high volume evacuation and suitable working distance are imperative to minimize contamination. Protective cover placed over the loupe prevents lenses from scratching. Surface debris on the lenses can be removed with gentle blowing and blotting. Disinfection of the devices should follow the manufacturer’s instructions and professional cleaning and servicing must be sought periodically to maintain its optimum function.³

Microscope Sterile Drapes for Surgical Microscopes

During use the microscope can be covered with sterile disposable drape. A surgical microscope drape is a large sterile plastic cover. It is cut in many forms and seamed together to fit different models of surgical microscopes. The clear plastic (polyethylene-based) material must be strong enough not to puncture when draped over the scope.
Following which the surfaces can be wiped with isopropyl alcohol.

Inspection of optical surfaces

During inspection, all optics must be handled in the cleanest area available (preferably a cleanroom or within a laminar flow bench). Proper equipment, such as powder-free cleanroom gloves or finger cots must be worn at all times to avoid grease and oils from being transferred to the optic.
Lens tissue paper, dust-free blowers, hemostats, cotton swabs, cotton tips will all be needed for cleaning optics. Reagent-grade isopropyl alcohol is used.
Scratches can result from improper cleaning methods.
Tip: Clean optics against a dark background so dust can be seen and eliminated more efficiently.
There are two ways in which an optic can be evaluated:
a. If the optic is being used in a laser-based system, contamination on the optic might cause the optic to scatter the laser light, thus reducing power and making the optic “glow.”
b. An optic can also be visually inspected by holding it below a bright light source and carefully viewing it at different angles. This will cause the light to scatter off the contamination enabling the viewer to see the various stains and dust particles.

Cleaning methods

Avoid touching the surface of the optic with unprotected fingers! Always wear powder-free gloves or finger cots. The first step in cleaning any kind of optic is to remove dust or loosely held particles by blowing them off the surface using a dust-free blower or a camel hair brush. This reduces the chance of scratching the optic during the actual cleaning. Other pressurized gas products are not recommended because the propellant could be released onto the surface in the form of liquid droplets.
NOTE: This is the only cleaning method allowed for bare metal, soft coatings and pellicles. These types of surfaces should never be touched.
2. Wipe method

If the optic cannot be taken out of its held position or if stronger cleaning is required, then the next step will be to wipe using lens tissue paper

• Use the blowing method first.
• Fold a piece of lens tissue paper to create a folded edge that is a little longer than the size of the optic. A hemostat is particularly suited to securely hold the folded tissue.
• Wet the folded edge of the tissue with isopropyl alcohol
• Wipe the optic with the lens tissue paper with one continuous motion. Apply some pressure on the wipe to remove stubborn stains.

Repeat this process, always with new lens tissue paper to eliminate depositing any contamination on the optic. It is usually better for cleaning laser optics exposed to particles (in an uncontrolled environment or outside of a vacuum chamber). If the size of the optic is very small, cotton tips can be used instead of lens tissue paper with the same procedure.
CAUTION: It is important that the tissue paper be dampened with alcohol before use and that the surface not be scrubbed back and forth, which would increase the likelihood of surface scratches or damage to a coating.
3. Soap solution method

If the optic contains contamination in the form of grease (fingerprints, etc.), methanol and acetone will tend to simply redistribute the grease. In this case, the optic will need to be cleaned with a soap solution. The soap solution should be a nonabrasive, mild solution without any additives. (Green soap works well for this.)

• Use the blowing method first.
• Use a soap solution and clean with the wipe method
• Cleaning with alcohol should be next.
• After rinsing, blow-dry with a dust-free blower to remove all water.

Solvents

Isopropyl alcohol is a safe and effective cleaner – except for cleaning aluminium coatings. Because alcohol reacts with aluminium, it should never be used on protected or bare aluminium-coated mirrors.

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