Reduce Aerosol Risk With Preprocedural Mouthrinse

It should be of no surprise that in the midst of a global pandemic, infection control and clinician safety are top of mind. To protect themselves and their patients, dental hygienists need to be equipped with a strong knowledge of disease transmission and preventive measures, such as the use of preprocedural mouthrinses.¹

Contaminated aerosols create a potential route of infection for arboviruses, alphaviruses, coronaviruses, and influenza type B.² The production of aerosols in a dental office is inevitable. While treating patients, dental hygienists are exposed to aerosols during prophylaxis, periodontal maintenance therapy, and scaling and root planing. Such therapeutic procedures use ultrasonic and sonic instruments, coronal polishing handpieces, and compressed air and water, all of which generate dental aerosols.

The highest concentration of aerosols has been found 1 foot to 2 feet from the patient’s mouth, which is precisely the clinician’s work area.³ Saini⁴ compared general dental procedures with dental hygiene procedures and found that the dental hygiene treatment produced higher microbial aerosol concentrations. The study also found that ultrasonic scaling yielded more aerosol production and potential for disease transmission than caries preparation performed by a dentist and dental assistant. As such, the United States Centers for Disease Control and Prevention (CDC) recommends clinicians avoid using aerosol-generating techniques, such as high-speed dental handpieces, air/water syringes, and ultrasonic scalers, and to focus on the use of hand instruments instead during the COVID-19 pandemic.⁵

Reducing Risk of Aerosols

Dental patients can transmit viruses and bloodborne or respiratory pathogens through splatter, droplets, and aerosols to other patients and dental staff.⁶ Ideally, such patients would refrain from proceeding with elective dental treatment until medically cleared, but individuals may be asymptomatic or simply unaware they are infected. Besides avoiding the use of any aerosol-generating procedure, following the standard precautions for oral health established by the CDC is key to minimizing the production and transmission of aerosols. The CDC defines standard precautions as “the minimum infection prevention practices that apply to all patient care, regardless of suspected or confirmed infection status of the patient, in any setting where healthcare is delivered.”⁷

The first step in reducing aerosol risk is personal protective equipment (PPE): wearing a surgical mask within 1 meter of the patient; donning a gown, gloves, and eye protection upon entering the room; and removing all equipment upon exiting the room.⁸ Next is using equipment, such as high-volume evacuation, which has been shown to reduce aerosols by 89.7% to 90.8%.³ Lastly, the use of a preprocedural mouthrinse can reduce contaminated aerosol production up to 94.1%.^1,6

Role of Preprocedural Mouthrinsing

The goal of having patients rinse prior to beginning dental treatment is to reduce the bacterial load in the oral cavity. While there is no evidence supporting the effectiveness of preprocedural mouthrinsing in the prevention of SARS-COV-2, the ability of some therapeutic ingredients to decrease transmission of pathogens suggests there may be efficacy in reducing the presence of the novel coronavirus in dental aerosols.⁹

Several mouthrinse ingredients are bactericidal—capable of killing bacteria—and bacteriostatic—preventing the reproduction of and proliferation of bacteria. Mouthrinses with chlorhexidine gluconate (CHX) and essential oils can rapidly reduce the level of bacteria found in dental aerosols.² Agents, such as ozonated water, CHX, and essential oils, are also capable of exerting significant antiviral effects against herpes simplex virus, human immunodeficiency virus, and influenza.²

Extensive research supports CHX as the gold standard in preprocedural mouthrinses.^10–12 In patients who rinse with CHX prior to dental treatment, the antimicrobial properties of CHX are activated as soon as dental aerosols are generated.⁴ Essential oils, such as eucalyptol, menthol, methyl salicylate, and thymolpopular, are also effective agents in preprocedural mouthrinses.¹³ Patients who rinse with essential oils for 30 seconds prior to dental treatment experience a reduction in viral contamination for up to 60 minutes.²

The goal of having patients rinse prior to beginning dental treatment is to reduce the bacterial load in the oral cavity.

Cetylpyridinium chloride (CPC), chlorine dioxide (ClO₂), povidone-iodine, and hydrogen peroxide have all been studied for their efficacy in reducing the bacterial or viral loads in contaminated aerosols.⁴ In a comparison study of CHX and ClO₂, the ClO₂ rinse was equally effective to CHX in its ability to decrease contamination in aerosols.⁴ Similarly, results from a study comparing a mouthrinse containing CPC, zinc lactate, and sodium fluoride with a CHX mouthrinse, the CPC rinse was equally effective to CHX in reducing bacterial contamination in aerosols.¹⁴ Additionally, CPC has been shown to lower the amount of bacteria produced during high-speed instrumentation.¹⁴

Povidone-iodine exhibits high levels of antiviral activity in mouthrinse, and has shown similar efficacy to CHX.^15,16 SARS-CoV-2 is contained within a lipid membrane, and research demonstrates that povidone-iodine can penetrate this membrane, reducing the potential for transmission.¹⁷ Another alternative is hydrogen peroxide. A study comparing the anti-gingivitis effects of CHX and hydrogen peroxide found that at levels above 1%, hydrogen peroxide yields several beneficial effects, including antimicrobial effects on bacteria, yeasts, fungi, viruses, and spores.¹⁸

Alternative Uses

Although most mouthrinses are used almost exclusively pre- and post-procedure, the investigation of alternative uses has emerged. When it comes to essential oils, preprocedural rinsing used in conjunction with preprocedural subgingival irrigation has proven to significantly decrease the level of bacteremia associated with subgingival ultrasonic scaling.² Moreover, as ultrasonic use, at least prior to the pandemic, was ubiquitous in dental settings, using mouthrinses as ultrasonic coolants may help reduce bacteria levels. For instance, cinnamon within the essential oil cinnamaldehyde has antibacterial, anti-inflammatory, and antifungal properties.² Although the research proving cinnamon’s efficacy as a bacteriostatic or bactericidal preprocedural mouthrinse ingredient is limited, a study did show that when used as an ultrasonic device coolant, the dental aerosol contamination was significantly lower.¹⁹

CONCLUSION

During the pandemic and after its conclusion, all infection control precautions should be maintained and executed at the highest level to not only protect the general public, but the oral health professionals serving at the forefront, as well. The use of a simple antimicrobial preprocedural mouthrinse can help promote a safe work environment and reduce the transmission of oral pathogens.

References

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2. Walsh LJ. Antiviral and antibacterial effects of preprocedural mouthrinses. Australasian Dental Practice. 2011;22(4):112–118.
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From Dimensions of Dental Hygiene. November 2020;18(10):16-18.