COVID-19 and the dental office

• What is COVID-19?

Coronavirus infection has been considered by the WHO a global pandemic. Since its origin, it has been a threat to world health, not so much because of its symptoms, but still because of its rapid spread and contagion and the respiratory complications it produces in patients with other chronic conditions.

The first outbreak of COVID-19 pneumonia originated in Wuhan in late December 2019. Since then, pneumonia infection has spread rapidly from Wuhan to most other provinces. Over 150,000 cases in over 140 countries are increasing exponentially daily, with Italy and Spain reporting the most cases daily, proliferating in the United States.

• Etiology

According to the latest studies, the coVID-19 virus, commonly known as coronavirus, is similar to SARS-CoV and SARS-CoV2 coronavirus middle eastern respiratory syndrome, i.e., of zoological origin. Moreover, it is closely related to a Chinese bat as a possible transmitter.

• Mechanisms of transmission

The main transmission mechanisms described are Pflügge drops, aerosols, and direct contact with contaminated surfaces.

• Incubation period

The incubation period is estimated at an average of 5-6 days, although there is evidence of periods close to 14 days.

• At-risk population

Epidemiological studies show that the population at most significant risk in terms of symptoms and complications is 65-80 years, although the people that act as a vector of infection to a greater extent are the ones between 25-30 years.

As for the professional sectors with the highest exposure rate, a recent article in The New York Times newspaper talks about the professions with the highest risk when it comes to catching and spreading the virus. This article puts dentistry at the top of the list as the profession with the highest risk due to several factors:

- patient care.

- the activity in the oral cavity and the presence of saliva

- working with ultrasound and rotating materials that produce aerosols.

• Symptomatology

Typical clinical symptoms of patients suffering from this new viral pneumonia are fever, cough, myalgia, or fatigue with an abnormal chest. Less common symptoms were sputum production, headache, hemoptysis, and diarrhea.

The most detailed breakdown of disease symptoms comes from a recent World Health Organization analysis of over 55,000 confirmed cases in China. These are the most common symptoms and the percentage of people who had them:

• Fever: 88%
• Dry cough: 68%.
• Fatigue: 38%.
• Coughing up sputum, or phlegm, from the lungs: 33%
• Shortness of breath: 19%.
• Bone or joint pain: 15%.
• Sore throat: 14%.
• Headache: 14%.
• Chills: 11%.
• Nausea or vomiting: 5%
• Blocked nose: 5%.
• Diarrhea: 4%
• Coughing up blood: 1%
• Swollen eyes: 1%

COVID-19 is a lower respiratory tract infection; most symptoms are felt in the chest and lungs. This differs from colds that cause an upper respiratory tract infection, where you have a runny nose and nasal congestion. These symptoms seem mostly absent for people with COVID-19, although they can occur. Recent studies add ageusia and anosmia to these symptoms in young patients.

• Possible transmission routes of COVID-19

Common transmission routes of the new coronavirus include direct transmission (coughing, sneezing, and droplet inhalation) and contact transmission (contact with oral, nasal, and ocular mucous membranes). Although common clinical manifestations of new coronavirus infection do not include eye symptoms, analysis of conjunctival samples from confirmed and suspected cases of COVID-19 suggests that transmission is not limited to the respiratory tract and that eye exposure may provide an effective way for the virus to enter the body.

Several studies have shown that respiratory viruses can be transmitted from person to person through contact or coarse or small droplets, and COVID-19 can also be transmitted directly or indirectly through saliva. In addition, a report of a COVID-19 infection in Germany indicates that such virus transmission can also occur through contact with asymptomatic patients.

Several studies have suggested that COVID-19 may be airborne through aerosols formed during medical procedures.

Dental treatments often involve surgical procedures using air or water syringes, high-speed turbines, micrometers, and ultrasonic scrapers. Unfortunately, these devices produce aerosols containing potentially infectious agents, such as those found in the patient's blood, saliva, and oral cavity.

Patient blood and saliva are spread as aerosols and droplets during dental treatments. Therefore, they are considered potential sources of cross-contamination, having the potential to cause microbial infections not only in patients but also in dental clinic staff. In addition, contaminating sprays and splashes can also spread to the surfaces of tools and equipment and the general dental office environment.

It is recommended that dentists and dental hygienists use personal protection

equipment such as masks, gloves, goggles, and gowns to protect themselves from exposure to infectious aerosols and splashes containing patient saliva and blood.

The distance of the aerosol spread, splashes, and contamination levels during dental treatment are always of great concern.

• How can we help and assist in Dentistry?

Dentists must be familiar with COVID-19 or, at least, with the mechanisms of prevention of direct infection, as well as possible cross-infection or the role of an important vector in the transmission routes of the virus, as we are with other types of conditions.

We must also know what kind of extra measures we must take at times of rapid virus spread, as in the global pandemic described by the WHO that we are currently experiencing.

Obviously, we are at a time when we are growing in wisdom and experience as the pandemic evolves, which is not ideal. Still, today, we are clear about some measures we can take in terms of prevention, taking into account, above all, the ease with which the virus can spread between the aerosols in the clinic and the pfflüge drops as the primary way of spreading the virus.

These recommendations are based on the "Guidelines for the Diagnosis and Treatment of Coronavirus Pneumonia," the "Guidelines for the Prevention and Control of Coronavirus Pneumonia in Medical Institutes," and the "Guidelines on the Use of Medical Protective Equipment and Control of Coronavirus Pneumonia" developed by the National Health Commission of the Chinese Government and the experience of the Eastern China Dental Hospital related to the prevention of COVID19.

- Patient assessment: the dentist must identify a suspected COVID-19 infection. In general, patients who are currently suffering from fever should not attend the consultation. Therefore, asking a few questions, even in a short telephone anamnesis, is essential to gather critical information that may lead to suspicions.

- The guidelines above advise against treating patients suspected of being carriers of COVID-19, postponing any treatment that is not considered urgent, at least during the time stipulated as quarantine, during which the patient will or will not develop the disease. And referring the patient to the hospital to monitor their symptoms and condition.

All these guidelines on the protocol of action emphasize knowing how to detect the information necessary to include the patient in one protocol or another by telephone. To do this, they advise asking a series of questions, such as

- Do you have or have you had a fever in the last 14 days?

- Have you had respiratory problems (including cough) during the last 14 days?

- Have you traveled to countries at risk in the last 14 days (although at this point, we will have to take into account that, according to the epidemiological data currently being considered, Spain is considered one of the countries at risk, with growth in infections similar to the most conflictive points such as Italy).

- Have you been in contact with people who have had a fever, cough, and/or breathing difficulties in the last 14 days?

If the answer to any of the questions is yes, and you do not have a fever or your body temperature is below 703.4 °F, we will postpone treatment if it is not considered urgent.

If the answer is yes to any of the questions, and the patient has a temperature above 703.4 °F, inform the patient of the possible infection.

If the answer is No to any of the questions, but the patient presents a fever above 703.4 °F, delay treatment unless it is considered urgent.

If the answer is No and there is no fever, postpone treatment if it is not urgent or treats with appropriate measures. 

At this point, it is essential to remember that, according to the World Health Organization (WHO), urgency can be defined as the fortuitous appearance in any place or activity of a problem of diverse cause and variable seriousness that generates the conscience of an imminent need of attention on the part of the subject who suffers it or his family.

Dental urgency is the sudden appearance of a pathological condition in the oral and maxillofacial area, which causes a spontaneous demand for attention, whose treatment must be immediate, undelayable, timely, and efficient, such as pain, abscesses, and trauma, which are the main pathologies that can cause with limitation of the patient's regular activity or that can pose a risk to the patient's general state of health.

• Hygiene and handwashing: transmission by contact and oro-fecal transmission have been described as frequent routes of virus transmission. For this reason, although as health personnel, we must do it frequently and abundantly during our daily practice, these guidelines encourage us to do it among patients, being a thorough and surgical wash to reduce as much as possible this way of contagion.
• Personal protection measures in the dental clinic: of the three levels described in terms of barrier measures, the guidelines advise us to use level 3 to prevent contagion. This level 3 consists of rubber protective glasses fitted to the face, a waterproof face shield, a disposable surgical cap, an ffp2/ffp3 mask, disposable waterproof gowns, and nitrile gloves. In any case, it would be for emergency treatment as advised, treating any patient as a possible virus transmitter.
• Pre-procedure mouthwashes: the National Health Commission of the Republic of China's guide to diagnosing and treating coronavirus pneumonia concludes that the rinses most commonly used in dental clinics, such as chlorhexidine rinses, do not appear to be effective in killing the virus. However, the virus is vulnerable to oxidation, so rinses with oxidative elements such as 1% hydrogen peroxide or 0.2% povidone-iodine are recommended.

Use of rubber dam: it has been shown to reduce the concentration of aerosols by 70%.

Turbines and handpieces with the anti-shrinkage system: handpieces and turbines without anti-shrinkage valves cause microbes, such as bacteria and viruses, to remain in the air hoses that pollute these ducts where the air comes out, and this can be a very noticeable cross-contamination route. The importance of using instruments and equipment that promote disinfection and prevent contamination of structures that can cause cross-contamination is fundamental in our cabinets.

Disinfection of the cabinet: we must disinfect the clinic and the cabinets according to the "protocol for the management of cleaning and disinfection of surfaces in the medical environment" (WS/T 512-2016) of the National Health Commission of the Republic of China. It is advisable to frequently disinfect any metal structure that is commonly touched, knobs and handles, elevator if there is one and railings... This protocol must be carried out after each patient as we may not know whether they are positive.

Instruments and material: it is advisable to keep the fabric and tools stored where we have the stock to move to the cabinet, only what we will use in each intervention.