An innovative risk-scoring system of dental procedures and safety protocols in the COVID-19 era

The Covid-19 pandemic, caused by SARS-CoV-2, has led to a global health crisis with safety and socio-economic issues. In the field of dentistry, this pandemic has highlighted the risk of infectious diseases with a clear impact on dental team and patients. In the past the most frightening pathogens were those transmissible predominantly through blood. Nowadays, and due to the SARS-CoV-2 pandemic, global security is being reconceptualised by studying prevention from infective air-borne agents, which can be diffused by the diffusion of saliva and secretions in the form of droplets and aerosol. The same phenomenon is occurring in the field of dentistry: procedures which were previously considered as trivial have increased in risk (e.g. scaling and irrigating) due to the heightened risk of spreading highly contaminated microbial aerosol. Today, the majority of the population is considered to be avoiding dental treatment except that involving pain or urgent in nature. And it can be predicted in the immediate future that these populations will fear infection from visiting the dental surgery, leading to a consequent potential increase in the price of treatments in terms of an increase in serious oral and dental diseases.

One basic principle for the recovery of any dental routine activity should be the recognized patient status of SARS-CoV-2: currently (in the emergency phase), it is advisable to perform double-phase triage (via the telephone and the surgery visit) [1]. However, in the future and in the absence of a reliable and safe test for SARS-CoV-2, the operator should consider each patient as potentially infectious, adopting individual prevention and protection measures. The main risk factors in dental practice include: a close physical relationship with the patient, coming into contact with saliva and blood, and frequent aerosol production (low level by air–water syringe or high level by rotating or ultrasonic/piezo tools).

The aim of this paper is to assess the efficacy of an innovative risk score for common dental procedures, which is based on the risk of past and principally the newest contaminant, that is, SARS-CoV-2. The authors have attempted to discern the level of infection risk relating to each dental practice, and to specify those safety procedures, advice and Personal Protective Equipment (PPE) to be deployed by the dental team. As a preliminary supposition, the authors state the requisite of recently reported fundamental postulates regarding safety protocols [1‐5], with near general agreement regarding their necessity.

The authors of this research analysed 42 common dental procedures as based on known SARS-CoV-2 transmission risks [1, 14]. In increasing order, many consider the parameters leading to different risk scores for the dental team and patients for each procedure to be: direct contact with saliva (score 1), direct contact with blood (score 2), production of low levels of spray/aerosol via air–water syringes (score 3), the production of high levels of spray/aerosol by use of rotating, ultrasound and piezoelectric tools (score 4); and the duration of the procedure (score 0.25 if ≤ 30 min, score 0.50 if 30–60 min, score 0.75 if ≥ 60 min). A procedure can accumulate multiple scores.

After this analysis of dental procedures, the authors classified the different dental procedures as: low [1‐3], medium [4, 5] or high (≥ 6) risk. The duration of the procedure also plays an important role in defining the severity of the risk: the authors have provided a purely indicative timing datum since it is an operator-dependent parameter. The safety protocol for each procedure has, therefore, been, matched and proposed on the basis of its final risk score.

The results showing the risk of dental procedures according the innovative risk-scoring system are shown in Table 1. The use of PPE according to the level of risk scored, as calculated by the authors, is displayed in Table 2.

Hitherto, classifying the risk of dental procedures according to the technical difficulties and the patients’ health status has been widely discussed in the literature. The emerging situation arising from the phenomenon of COVID-19 has compelled many dental practitioners to re-classify dental procedures according to the risk of infectious contagion due to the airborne pathogens, in addition to blood pathogens. This revised risk-classification is based on greater or lesser amounts of pathogen agents, which are capable of infecting those visiting the dental surgery after direct contact with saliva and/or blood and/or aerosol/spray production. However, the grade of risk is highly influenced by the duration of contact or production of infectious materials and the related exposure time. Statistical probability studies have confirmed that, after the current and serious pandemic wave can be said to have ceased, the following should be available: repeated and intermittent social distancing, an expansion of intensive care facilities and the availability a vaccination and therapeutic practice [15, 16]. It is evident that modern working practices and modes of modern life will have to be re-evaluated to avoid the onset of new epidemics of—SARS-CoV-2 or other pathogens.

Until a few months ago, scientific knowledge and attention focused on the fact that viruses, bacteria and mycetes could be frequently present in the human mouth. Their presence in saliva may cause the direct transfer of infectious agents from infected individuals to healthy people or blood-derived contamination could transmit several infectious agents to unprotected healthy subjects [17‐20]. However, it has recently been confirmed that SARS-CoV-2 can be transmitted by a positive-for SARS-CoV-2 person breathing in a room [21‐25].

Thus, it can be stated that the majority of dental procedures, producing droplets and potentially highly-contaminated microbial aerosol, is extremely dangerous for all those present in the treatment room [1, 14, 23, 26] as they are generated by the typical use of ultrasonic/piezoelectric devices or rotating tools [27]. This risk is related to the number of pathogens present in the aerosol/spray, and instruments, such as rotating tools, ultrasonic scaler and piezo tools, produce a greater amount of spray and aerosol than other tools like air–water syringes. Droplets and aerosols contain a large-particle spatter of water, saliva, blood and microorganisms. This spatter travels a short distance to settle quickly, landing either on the floor (near to sanitized surfaces), the dental health care team or the patient. Spray may also contain a quantity of aerosol, which can remain airborne for extended periods of time and it may be inhaled. It has long been recognized that saliva can contain potential pathogens in quantities sufficient to infect other individuals [17, 18]. It is also known that blood-borne contamination can transmit several infectious agents to unprotected healthy subjects [19, 20]. This is, therefore, the rationale for the authors to propose the innovative COVID-19 risk-classification of dental practices, as outlined in this paper. For example, the use of rotating tools in the execution of abutment tooth preparation or the deployment of an ultrasonic scaler have become extremely dangerous since they are capable of spreading pathogens in the room through spray/aerosol. On the other hand, the manual reduction of a dislocation of the jaw or performing a dental impression are now considered by many to be less dangerous than was the case previously. With the aim of protecting all health workers, the authors suggest adhering to the security protocols (Table 2), as emanating from the recommendations of the Italian Health Ministry [28].

It is the authors’ considered opinion that this innovative risk-classification can assist dental operators adhering to safety procedures and PPE provisions in order to managing dental practices in the light of the new contagious landscape. The authors are also aware that this pandemic is imposing huge changes in: the performing of telephone-triage, planning patient protocols, the number of patients/day, the timing of procedures, sanitizing the treatment room, calculating revised costs and revenues, and in the fundamental relationship of trust with their community of patients.