Transmission Precautions for Dental Aerosols

What is COVID 19?

The virus is not an living organism but a protein molecule consisting of DNA covered by a layer of lipid which can absorbed by all the cells such as nasal, mucosal, ocular and induces genetic mutation amongst the population.

How does COVID 19 survive?

The viral genome of corona virus is fragile and is protected by a layer of fat. The virus has the tendency to stay on surfaces for atleast 6-9 hours, also called as FOMITES. These are nothing but contaminated surfaces which cross infect other human beings. This virus has a pH of  5.5 to 8.5 That is why any soap or detergents is the best remedy to prevent this virus.

By dissolving the fat layer, the protein molecule disperses and breaks down on its own. Alcohol or any mixture with alcohol over 65% dissolves the fat, especially the external lipid layer of the virus. Any mix with 1 part bleach and 5 parts water directly dissolves the protein, breaks it down from the inside. Oxygenated water helps long after soap, alcohol and chlorine, because peroxide dissolves the virus protein, but you have to use it pure and it hurts your skin.

The virus molecules remain very stable in external cold,or artificial as air conditioners in houses and cars. Theyalso need moisture to stay stable, and especially darkness. Therefore, dehumidified, dry, warm and bright environments will degrade it faster. UV LIGHT on any object that may contain it breaks down the virus protein.

COVID-19 virus can persist on inanimate surfaces like metal, glass or plastic for upto 9 days, but can be efficiently inactivated by surface disinfection procedures with 62–71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite within 1 minute. Other biocidal agents such as 0.05–0.2% benzalkonium chloride or 0.02% chlorhexidine digluconate are less effective.

    CLINICAL FEATURES OF COVID 19

Incubation period

The exact incubation period is not known. It is presumed to be between 2 to 14 days after exposure, with most cases occurring within 5 days after exposure.

The spectrum of illness severity

Most infections are self limiting. COVID-19 tends to cause more severe illness in elderlypopulation or in patients with underlying medical problems.

• Mild illness was reported in 81% patients

• Severe illness ( Hypoxemia, >50% lung involvement on imaging within 24 to 48

hours) in 14%

• Critical Disease (Respiratory failure, shock, multi-organ dysfunction syndrome) was

reported in 5 percent

Age affected

• Mostly middle aged (>30 years) and elderly.

• Symptomatic infection in children appears to be uncommon, and when it occurs, it is

usually mild

Common clinical features at the onset of illness were:

•Fever in 88%

•Fatigue in 38%

•Dry cough in 67%

•Myalgias in 14.9%

•Dyspnea in 18.7%

Pneumonia appears to be the most common and severe manifestation of infection. In this group of patients breathing difficulty developed after a median of five days of illness. Acute respiratory distress syndrome developed in 3.4% of patients.

Other symptoms

•Headache

•Sore throat

•Rhinorrhea

•Gastrointestinal symptoms

PRECAUTIONS TO BE ADOPTED IN DENTISTRY

 ü  What are aerosols in dentistry ?

Dental procedures that use low- or high-speed handpieces, lasers, electrosurgery units, ultrasonic scalers, air polishers, prophy angles, hand instruments or air/water syringes can create bioaerosols and spatter. Ultrasonic scalers and high-speed handpieces produce more airborne contamination than any other instrument in dentistry. Inhalation of airborne particles and aerosols produced during dental procedures may cause adverse respiratory health effects and bidirectional disease transmission.

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.

ü  What measures do we take to protect ourselves from COVID 19?

The risks of dental aerosols can be reduced with

Ø  The use of high-velocity air evacuation

Ø  Preprocedural antimicrobial mouthrinses, flushing waterlines at the beginning of the workday and between each patient,

Ø  Wearing personal protective equipment (PPE)

Ø  Using air purifications systems.

These recommendations are  published by the CDC as  Summary of Infection Prevention Practices in Dental Settings: Basic Expectations for Safe Care.

High velocity air evacuation

The high-volume evacuator’s (HVE) large diameter (> 8 mm) allows for removal of high volumes of air in a short time, which reduces the amount of bioaerosols by up to 90%.^9,1

  

  Preprocedural antimicrobial mouthrinses

Alcohol

Ethyl alcohol, at concentrations of 60%–80%, is a potent virucidal agent inactivating all of the lipophilic viruses (e.g., herpes, vaccinia, and influenza virus) and many hydrophilic viruses (e.g., adenovirus, enterovirus, rhinovirus, and rotaviruses but not hepatitis A virus (HAV)  or poliovirus)

Hydrogen peroxide

Hydrogen peroxide is active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores. A 0.5% accelerated hydrogen peroxide demonstrated bactericidal and virucidal activity in 1 minute and mycobactericidal and fungicidal activity in 5 minutes. Bactericidal effectiveness and stability of hydrogen peroxide in urine has been demonstrated against a variety of health-care–associated pathogens; organisms with high cellular catalase activity (e.g., S. aureus, S. marcescens, and Proteus mirabilis) required 30–60 minutes of exposure to 0.6% hydrogen peroxide for a 10⁸ reduction in cell counts, whereas organisms with lower catalase activity (e.g., E. coli, Streptococcus species, and Pseudomonas species) required only 15 minutes’ exposure.

Commercially available 3% hydrogen peroxide is a stable and effective disinfectant when used on inanimate surfaces. It has been used in concentrations from 3% to 6% for disinfecting soft contact lenses (e.g., 3% for 2–3 hrs) , tonometer biprisms , ventilator, fabrics, and endoscope. Hydrogen peroxide was effective in spot-disinfecting fabrics in patients’ rooms

Idophors

  Iodine can penetrate the cell wall of microorganisms quickly, and the lethal effects are believed to result from disruption of protein and nucleic acid structure and synthesis.

   Published reports on the in vitro antimicrobial efficacy of iodophors demonstrate that iodophors are bactericidal, mycobactericidal, and virucidal but can require prolonged contact times to kill certain fungi and bacterial spores.

PPE – Personal Protective Equipment

Standard precautions, as outlined by the CDC, involve the use of PPE.

Ø  Primary PPE includes donning properly fitting gloves and surgical masks, protective eyewear with solid side shields or face shield, and protective clothing/disposable gowns.

Ø  This equipment should be worn whenever there is a potential to encounter spray or spatter during patient care, and while disinfecting the treatment area (as noted, bioaerosols remain suspended for 30 minutes to two hours posttreatment).

Ø  Masks and gloves should be changed between patients; moreover, all PPE should be changed if torn, wet or visibly soiled.

Ø  If providing care for patients with a known infectious disease, the National Institute for Occupational Safety and Health (NIOSH) requires the wearing of a NIOSH-certified particulate-filter respirator. To reduce disease transmission, all PPE must be removed prior to exiting the treatment area.

   How to tackle patients in a clinical Setting during    

  COVID-19  breakout?

ü Telephonic consulation : This will help the clinician to form a provisional diagnosis based on history given by the patient.

ü Patient can be segregated into two categories : Aerosol producing  procedures & Non- aerosol producing procedures.

ü Appoint the patient. Keep the aersol producing procedure in the end of the day.

ü Create a digital COVID history form, asking patient about any history with the disease, or close contact with any relative who had an exposure. Save this data methodically.

ü Instruct the patient to not get an accompanying person, unless necessary.

ü Tell the patient to show his AAROGYA SETU APP when they visit the clinic.

ü Keep a pulse oximeter in  the waiting room, to check the vitals of the patients before commencing the procedure. Any patient with high temperature, low oxygen saturation should be deferred from the treatment.

ü Take an informed consent and digitalise the information or data.

Post COVID era in dentistry is going to be tough and testing. We are more prone to viral load because of close proximity to the patients. Prevention is the only cure in sucb a health emergency.

BIBLIOGRAPHY

SOURCES AND ARTICLES :

1.   Transmission Precautions for Dental Aerosols

Understanding the risk posed by aerosols will help minimize the possibility of infection transmission during dental procedures.

By Kristin Baumann, RDH, MPH, Michelle Boyce, RDH, BSDH, DHSc and Donna Catapano-Martinez, CDA, RDH, DHSc

2.              INTERNATIONAL PULMONOLOGIST’SCONSENSUS ON COVID-19. Chief Editors Dr. Tinku Joseph (India), Dr. Mohammed Ashkan (Iran)

3.              https://www.cdc.gov/infectioncontrol/guidelines/disinfection/disinfection-methods/chemical.html