Occupational COVID-19 risk to dental staff working in a public dental unit in the outbreak epicenter

OBJECTIVE

The management of the COVID-19 outbreak occurred in Lombardy (Italy) implied that non-COVID-19 health care was remodeled, limiting adequate resources in non-hospital public dental healthcare settings. This situation offered the opportunity to investigate the occupational COVID-19 risk to dental staff in public non-hospital dental units.

METHODS

An infection control protocol was designed for dental health care in the Territorial Health and Social Services Authority (ASST) "Melegnano and Martesana" (Milan). Since specific guidance from central authorities was lacking, information was gathered from international public health organizations. The probability to visit asymptomatic COVID-19-infected patients was estimated, and the occupational risk to dental staff was calculated.

RESULTS

The probability to visit asymptomatic patients passed from 1.2% (95% confidence interval -95 CI, 0.6%-2.5%) in the first period (20 February-15 March 2020) to 11.1% (95 CI, 5.8%-23.6%) in the second period (16 March-30 April). Dentists and dental assistants did not develop COVID-19, while one nurse did, the nature of her occupational risk was unclear, as nurses provided prevalently non-dental health care. The probabilities of developing COVID-19 per worked hour per person excluding and including this uncertain situation were 0.0% (95 CI, 0.0%-3.2%) and 0.9% (95 CI, 0.1%-4.7%).

CONCLUSION

Relatively simple infection control procedures were enough to control occupational COVID-19 risk during the outbreak.

Tuberculosis: Occupational risk among dental healthcare workers and risk for infection among dental patients. A meta-narrative review

OBJECTIVES

Tuberculosis transmission among healthcare workers (HCWs) and patients is due to the level of Mycobacterium tuberculosis (MT) circulation in the community and in the healthcare settings where HCWs are active. In contrast, most papers about dentistry report that dental HCWs (DHCWs) and patients are at relatively high risk, mainly based on tuberculosis case series that occurred in the 80's-90's. This meta-narrative review was designed to evaluate the tuberculosis risk in dentistry accounting for the historical-geographical contexts.

DATA

All available studies reporting data on MT infection (active/latent tuberculosis, tuberculin skin test) among patients and DHCWs.

SOURCES

PubMed, Scopus, GOOGLE Scholar.

KEYWORDS

MT/tuberculosis and dentistry/dentist/dental/dent*.

RESULTS

238 of the 351 titles were excluded because did not concern dental healthcare providing, 94 papers were excluded because they did not provide original data. Thirteen studies on occupational risk, nine on transmission to patients remained. Some, often non-confirmed, cases of MT infection among patients were reported in specific historical-geographical contexts where MT was endemic. The risk of active pulmonary tuberculosis transmission from infected DHCWs to patients is minimal today, provided that the basic infection control guidelines are applied. The development of active tuberculosis among DHCWs is occasional and is associable to MT circulation rather than dental healthcare providing.

CLINICAL SIGNIFICANCE

Tuberculosis transmission in dental healthcare settings was due to the lack of basic infection control measures, while the risk is acceptable (i.e., similar to the general population) nowadays. Therefore, tuberculosis transmission can be safely prevented wearing gloves and surgical mask and providing regular air changes in the operative and non-operative dental healthcare settings. Precautionary Principle-based measures are implementable when patients with active pulmonary tuberculosis are routinely treated.

Ocular Manifestations of Ebola Virus Disease: An Ophthalmologist's Guide to Prevent Infection and Panic

Ebola virus disease (EVD—formerly known as Ebola hemorrhagic fever) is a severe hemorrhagic fever caused by lipid-enveloped, nonsegmented, negative-stranded RNA viruses belonging to the genus Ebolavirus. Case fatality rates may reach up to 76% of infected individuals, making this infection a deadly health problem in the sub-Saharan population. At the moment, there are still no indications on ophthalmological clinical signs and security suggestions for healthcare professionals (doctors and nurses or cooperative persons). This paper provides a short but complete guide to reduce infection risks.

Risk of Methicillin-Resistant Staphylococcus aureus Transmission in the Dental Healthcare Setting: A Narrative Review

Objective.

Information on the risk of methicillin-resistant Staphylococcus aureus (MRSA) infection transmission in dental healthcare settings was incomplete only few years ago; therefore, MRSA infection control guidelines were necessarily based on data extrapolated from other fields. Recently, publication of specific studies have made it possible to review such risk.

Methods.

Studies of MRSA infection in dentistry were searched for using EMBASE, MEDLINE, and Google and were allocated into the following sections: (1) direct evidence: documented cases of MRSA transmission in dentistry; (2) indirect evidence: carriage rates among dental healthcare providers (DHCPs) and patients (high carriage rates suggest that transmission is likely); (3) speculative evidence: MRSA occurrence in the dental environment (high environmental contamination probably increases the risk of infection); and (4) speculative evidence: MRSA carriage in human dental plaque and saliva (oral carriers may spread MRSA in the environment during dental therapy, with consequent environmental contamination and probable increased risk of infection).

Results.

Our findings were as follows. First, transmission has been ascertained during surgical interventions, particularly in surgical units and among head and neck cancer patients. Second, carriage rates among DHCPs were lower than those among other healthcare workers. Carriage rates among adult patients were low, whereas among pedodontic and special care patients rates were higher than those in the general population. Third, MRSA has been detected in the environment of emergency and surgical units and in dental hospitals. Some individuals in poor general condition were oral MRSA carriers.

Conclusions.

The occupational risk of MRSA infection among DHCPs is minimal. Among special patients (eg, special care, hospitalized and cancer patients) the risk of infection is high, whereas among the remaining patients undergoing conventional therapy such risk is probably low.

Effect of disposable barriers, disinfection, and cleaning on controlling methicillin-resistant Staphylococcus aureus environmental contamination

BACKGROUND

Environmental contamination and transmission of methicillin-resistant Staphylococcus aureus (MRSA) have been reported in dental health care settings. National professional dental associations recommend controlling surface contamination using disposable barriers or disinfection. Because these procedures may be costly, impractical, and/or toxic, we compared their effect against traditional detergent-based cleaning for decontaminating a dental chair sprayed with MRSA.

METHODS

Five MRSA strain suspensions were aerosolized to give a density of approximately 10 colony-forming units/cm(2) MRSA on the dental chair 5 minutes after dispersal. Three different decontamination protocols were applied: protocol 1: disposable barriers positioned before aerosol production and removed after 5 minutes; protocol 2: disinfection (wipe-rinse method) with 1:10 dilution of 5.25% to 6.15% sodium hypochlorite solution; protocol 3: cleaning (wipe-rinse method) with a sodium-lauryl-sulphate-based detergent. Contact plates containing Mannitol Salt Agar were used to assess the level of MRSA contamination.

RESULTS

All 3 protocols decreased MRSA surface load by >99%. Residual densities on the dental chair were 0.030 ± 0.010 (protocol 1), 0.029 ± 0.09 (protocol 2), and 0.030 ± 0.011 (protocol 3) colony-forming units/cm(2).

CONCLUSION

Cleaning (wipe-rinse method) using a sodium-lauryl-sulphate-based detergent demonstrated equivalence with disposable barrier placement or disinfection-based protocol for reducing MRSA contamination on dental chairs. This has practical and cost implications for controlling MRSA transmission in dental health care settings.

Detection of oral streptococci in dental unit water lines after therapy with air turbine handpiece: biological fluid retraction more frequent than expected

AIM

Oral streptococci detected in water from dental unit water lines (DUWLs) are a surrogate marker of patients' biological fluid retraction during therapy. We investigated oral streptococci detection rate in DUWLs in a representative sample of private offices in real-life conditions.

MATERIALS & METHODS

Samples of nondisinfected water (100 ml) were collected from the DUWL designated for the air turbine handpiece in 81 dental units, immediately after dental treatment of patients with extensive air turbine handpiece use. Water was filtered and plated on a selective medium for oral streptococci and, morphologically, typical colonies of oral streptococci were counted. The lowest detection limit was 0.01 CFU/ml.

RESULTS

The oral streptococci detection rate was 72% (95% CI: 62-81%), with a mean level of 0.7 CFU/ml. Oral streptococci detection was not affected by handpiece age or dental treatment type, but was associated with dental unit age.

CONCLUSION

Biological fluid retraction into DUWLs during patient treatment and, possibly, the risk for patient-to-patient blood- or air-borne pathogen transmission are more frequent than expected.

Long-term survival curve of methicillin-resistant Staphylococcus aureus on clinical contact surfaces in natural-like conditions

We investigated methicillin-resistant Staphylococcus aureus (MRSA) survival on a noncritical environmental surface in real-life conditions (dental chair located in a box of a Dentistry Department, subjected to microclimate variations and presence of people) and with a plausible baseline inoculum (5-log colony-forming units) in contrast to survival that has been frequently tested in laboratory conditions and/or using high baseline levels. We tested 5 freshly isolated sporadic strains and observed a drastic MRSA fall (>90%) 15 minutes after exposure to the environment. After 4 months, we detected MRSA at very low levels in 9 out of 25 tests. The MRSA survival curve showed that the velocity of log count decrease, highest soon after exposure, tended to decrease progressively. Thus, whereas the risk for infection through shared surfaces is probably minimal, the risk for MRSA diffusion in the community is high.

Dentists' awareness toward vaccine preventable diseases

Effective infection control in dentistry is unfeasible without an adequate immunization program for dental health care providers (DHCPs). Such an assumption is demonstrated for some vaccine preventable infectious diseases (VPIDs), such as Hepatitis B, Influenza and Varicella. However, excluding Hepatitis B vaccine, immunization programs for DHCPs are few and often unclear about which vaccinations are recommended, thus leading to generally low awareness and consequent low vaccination rates. This survey investigated dentists' awareness toward VPIDs. At the moment of registration to a dental congress, a questionnaire regarding the immunization status toward VPIDs was anonymously filled in by 379 Italian dentists (86% of the contacted dentists), with at least fifteen years of activity. DHCP specific awareness was considered high if dentists reported to have controlled the serum level of anti-HBs during the last ten years and have received seasonal influenza vaccine annually. Awareness toward VPIDs was classified high if dentists reported to be immune against six or seven of the following VIPDs, Hepatitis B, Influenza, Varicella, Measles, Mumps, Rubella and Tetanus. DHCP specific awareness resulted high for 32.5% of subjects and low for 31.1%. None of the subjects reported high awareness toward VPIDs, while for 60% of them, such awareness was low (immunization status reported for none or one of the seven VPIDs). Low dentists' awareness stresses the need for a transparent immunization program which is effective in controlling VPID transmission in the dental health care settings and focuses on those VPIDs which pose a true risk of infection for DHCPs and patients.