Microbial contamination of contact lenses after scaling and root planing using ultrasonic scalers with and without protective eyewear: A clinical and microbiological study

Aerosol-generating procedures and associated control/mitigation measures: Position paper from the Canadian Dental Hygienists Association and the American Dental Hygienists' Association

Background

Since the outbreak of COVID-19, how to reduce the risk of spreading viruses and other microorganisms while performing aerosolgenerating procedures (AGPs) has become a challenging question within the dental and dental hygiene communities. The purpose of this position paper is to summarize the evidence of the effectiveness of various mitigation methods used to reduce the risk of infection transmission during AGPs in dentistry.

Methods

The authors searched 6 databases-MEDLINE, EMBASE, Scopus, Web of Science, Cochrane Library, and Google Scholar-for relevant scientific evidence published between January 2012 and December 2022 to answer 6 research questions about the risk of transmission, methods, devices, and personal protective equipment (PPE) used to reduce contact with microbial pathogens and limit the spread of aerosols.

Results

A total of 78 studies fulfilled the eligibility criteria. The literature on the risk of infection transmission including SARS-CoV-2 between dental hygienists and their patients is limited. Although several mouthrinses are effective in reducing bacterial contaminations in aerosols, their effectiveness against SARS-CoV-2 is also limited. The combined use of eyewear, masks, and face shields is effective in preventing contamination of the facial and nasal region while performing AGPs. High-volume evacuation with or without an intraoral suction, low-volume evacuation, saliva ejector, and rubber dam (when appropriate) have shown effectiveness in reducing aerosol transmission beyond the generation site. Finally, the appropriate combination of ventilation and filtration in dental operatories is effective in limiting the spread of aerosols.

Discussion and Conclusion

Aerosols produced during clinical procedures can pose a risk of infection transmission between dental hygienists and their patients. The implementation of practices supported by available evidence will ensure greater patient and provider safety in oral health settings. More studies in oral health clinical environments would shape future practices and protocols, ultimately to ensure the delivery of safe clinical care.

Effect of aloe vera as a preprocedural rinse in reducing aerosol contamination during ultrasonic scaling

Background:

The use of preprocedural mouth rinse is one of the recommended ways to reduce aerosol contamination during ultrasonic scaling. Different agents have been tried as preprocedural mouth rinse. Chlorhexidine and povidone-iodine significantly reduce the viable microbial content of aerosol when used as a preprocedural rinse. Studies have shown that aloe vera (AV) mouthwash is equally effective as chlorhexidine in reducing plaque and gingivitis. There is no published literature on the role of AV as a preprocedural mouth rinse. Hence, this study compared the effect of 94.5% AV to 0.2% chlorhexidine gluconate (CHX) and 1% povidone-iodine (PVP-I) as preprocedural mouth rinses in reducing the aerosol contamination by ultrasonic scaling.

Materials and Methods:

Sixty subjects were divided into three groups based on the preprocedural rinse use (0.2% CHX, 1% PVP-I, and 94.5% AV). Ultrasonic scaling was done for 20 min in the same closed operatory for all the subjects after keeping blood agar plates open at two standardized locations. Colony forming units (CFUs) on blood agar plates were counted, and predominant bacteria were identified after incubation at 37°C for 48 h.

Results:

There was statistically significant difference in the CFU counts between CHX group and PVP-I group and between AV group and PVP-I group. There was no difference between CHX group and AV group at both the locations.

Conclusion:

94.5% AV as a preprocedural rinse is better than 1% PVP-I and comparable to 0.2% CHX in reducing CFU count.

A pilot study of occupational exposure to pathogenic microorganisms through lip cosmetics among dental hygienists

Objectives

In dental clinics, dental hygienists are exposed to aerosolized pathologic bacteria, which can be transmitted to the oral cavity via lip cosmetics. Accordingly, such contamination poses a consistent health risk among staffs. Our study examined the bacterial contamination of lip cosmetics used by dental hygienists while in a clinic setting.

Methods

Sixteen dental hygienists were surveyed regarding their job assignments and habits associated with lip cosmetic. Subsequently, microorganisms were analyzed in collected samples of the hygienists' lip cosmetics using colony‐forming unit (CFU) assays, 16s‐rDNA polymerase chain reaction, and DNA sequencing.

Results

Notably, 81.3% of the submitted lip cosmetic samples were contaminated, with bacterial CFUs ranging from undetectable to innumerable. Many samples (43.8%) exceeded the microbial limits of cosmetic contamination. Of the lip cosmetic used for more than 6 months, 60% exceeded the microbial limit. When wearing a mask every time, only one of the six samples exceeded the microbial limit. More frequent dental mask changing was associated with a lower likelihood that the cosmetic sample would exceed the microbial limit. No samples from hygienists who changed their masks four times a day exceeded the microbial limit, compared to 33.3% from hygienists who only changed the mask when it became wet. Most isolated bacteria were gram‐positive, facultative anaerobic, asporogenic, and opportunistically pathogenic, and the most prevalent species were Staphylococcus aureus, Streptococcus salivarius, and Staphylococcus epidermidis.

Conclusion

Our findings indicate that dental staff, including dental hygienists, should exercise more careful workplace habits, particularly with regard to infection control and cosmetic use.