As the COVID-19 pandemic tragically unfolds in the United States and other countries, regulatory bodies around the world are trying to provide specific guidelines for healthcare professionals during these unparalleled times.
The pandemic undeniably has affected the general delivery of healthcare, particularly in dentistry. The recommendations from the World Health Organization (WHO), which include delaying all non-essential dental treatments, have led to great turmoil among the dental community worldwide as well.
Fortunately, robust national organizations such as the ADA have openly disagreed with WHO. In fact, there has been a lack of evidence to support WHO’s guidelines in the context of the negative impact of oral health in general health.
Oral Diseases and General Health
Since the theory of focal infection, the amount of evidence linking oral conditions to general health has increased dramatically. In terms of research, periodontitis leads the way due to its clear potential to cause damage elsewhere in the body. Strong evidence supports its contribution to several conditions, including cardiovascular disease, diabetes, respiratory conditions, Alzheimer’s disease, pre-term birth, cancer, and others.
Particularly of interest for the COVID-19 pandemic, periodontitis has been demonstrated to have a negative impact on respiratory conditions and lung function, as evidenced in several randomized clinical trials. They all point to the importance of the connection between oral bacteria and the respiratory tract.
In our recent review study, we looked into previous studies that investigated the relationship between periodontitis and general inflammation, with a focus on respiratory problems. This study will be published in the Journal of the California Dental Association in October 2020.
From the literature, we know that untreated periodontitis causes inflammation and increases pro-inflammatory cytokines such as IL-6 in the general circulation. We also know that IL-6 has been considered as a critical predictor for respiratory complications in COVID-19.
A study from Germany found that hospitalized COVID-19 patients had a 22 times higher chance of needing a ventilator. Hence, it is not overstated to conclude that periodontitis can increase the risk of respiratory complications in COVID-19 patients. Another study discussed the importance of dental plaque and oral hygiene in COVID-19 infection.
Recently, a study on hospitalized COVID-19 patients in Japan provided remarkable information to confirm the importance of dental plaque for virus shedding. The researchers followed eight COVID-19 patients who were over the acute symptomatic phase, but remained positive to SARS-CoV-2.
In these patients, the virus was still detected despite recovery after 15.1 days on average. However, two patients remained positive for the virus for 44 and 53 days. Those two patients were not performing daily oral hygiene due to mental and/or psychiatric disorders, and they were instructed to start toothbrushing and use mouthwash with help from nurses. Four to nine days after oral hygiene was initiated, both patients tested negative.
Despite the small sample, the authors highlighted the importance of oral hygiene and the role that the oral microbiome can play as a reservoir for SARS-CoV-2, which is crucial for infection and transmission.
Several pathways can explain why local infection and inflammation in the mouth can affect the rest of the body, including the entrance of oral bacteria and/or their toxic products into the systemic circulation, systemic inflammation, endothelial dysfunction, gut dysbiosis, and local lung changes.
As obvious as it seems that the mouth is not separate from the body and that oral bacteria can have negative effects on other organs, delaying dental treatment underestimates the interconnectedness between mouth and body.
What About Transmission Through Dental Practices?
Dentistry has always set high standards for infection control. Treating every single patient as a potential carrier for a contagious disease, such as hepatitis and HIV, has long been the norm to decrease occupational health issues and cross-infection among the dental community.
Though aerosols have been pointed out as a potential culprit in the context of COVID-19 spread, no current studies show that dental-generated aerosols have viable viral particles. Only studies using viral culture can provide data on the infectivity of dental aerosols, as PCR tests can confirm the presence of minute amounts of viral RNA, but cannot necessarily confirm the presence of infectious viruses, according to one study.
Dental aerosols are different from medical aerosols because they result mainly from water irrigation, having the potential to dilute viral particles. Besides, the high-volume evacuation systems used in dentistry significantly decrease aerosols, another study reports.
Moral Versus Evidence-Based Decisions
Sometimes moral decisions must be made given the limited amount of scientific evidence on a certain topic until more studies are available. Nonetheless, the evidence on the deleterious effects of untreated oral diseases in the literature is compelling.
Currently, there are multiple missing links about the transmissibility of SARS-CoV-2 in dental clinics, particularly in aerosols. Also, there has been no data to suggest higher infection rates among dentists and dental staff and higher risk for patients to become infected as a result of dental treatment.
Thus, WHO’s moral decision to delay non-essential dental interventions might have been relevant at the beginning of the pandemic due to the urgency to protect health professionals and patients. But as the pandemic turns into a long-term reality, this decision has become unsubstantiated, as delaying treatment of oral conditions can deteriorate general health.
Dr. Christopher H. Fox, CEO of the International Association for Dental Research and American Association for Dental Research (IADR and AADR), said recently that WHO’s guidance is not intended to override national guidelines. However, considering the impact that WHO has on the general public, we urge its decision-makers to change its current guidelines to consider the impact of untreated oral conditions and plaque accumulation on general health and COVID-19.
As ADA President Chad P. Gehani highlighted, oral health cannot be ignored as it constitutes an integral part of overall health. Thus, essential healthcare cannot be complete without dentistry.
It is important to note that most patients who have periodontal disease present no obvious pain. Hence, it is easy to be ignored despite the hidden source for chronic infection and inflammation.
Prevention and treatment of oral diseases can have a positive impact on COVID-19 directly and indirectly—directly because it can reduce local and consequently general inflammation, and indirectly because it decreases the risk for other conditions that are linked to higher COVID-19 mortality, such as cardiovascular disease and diabetes.
The dedication and commitment of dental professionals to the provision of indispensable healthcare services during these challenging times deserve to be fully recognized and supported by all health organizations, given the importance of oral health for general health and well-being.
Dr. Molayem received both his bachelor of ats in history and DDS at the UCLA School of Dentistry. Thereafter, he completed a specialty program in periodontics at the Herman Ostrow USC School of Dentistry. He is the founder of both the UCLA and USC Journals of Dental Research, which have been going on for 13 and 11 years, respectively. He has lectured and has published in dental implants and periodontics and is the cofounder of Synergy Specialists, the largest agency for travelling dental specialists in the United States. Dr. Molayem has been practicing periodontics in a private practice setting in Southern California for the past 10 years. More recently, he has been conducting research and has published the most comprehensive connection to date between the mouth and COVID-19 in the Journal of the California Dental Association. He can be reached at smolayem@gmail.com.
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