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
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
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.
- Narayana TV, Mohanty L, Sreenath G, Vidhyadhari P. Role of preprocedural rinse and high volume evacuator in reducing bacterial contamination in bioaerosols. J Oral Maxillofac Pathol. 2016;20:59–65.
- Walsh LJ. Antiviral and antibacterial effects of preprocedural mouthrinses. Australasian Dental Practice. 2011;22(4):112–118.
- Akanksha S, Shiva Manjunath RG, Deepak S, et al. Aerosol, a health hazard during ultrasonic scaling: a clinico-microbiological study. Indian J Dent Res. 2016;27:160–162.
- Saini R. Efficacy of preprocedural mouth rinse containing chlorine dioxide in reduction of viable bacterial count in dental aerosols during ultrasonic scaling: a double-blind, placebo-controlled clinical trial. Dental Hypotheses. 2015;6(2):65–71.
- United States Centers for Disease Control and Prevention. Guidance for Dental Settings. Available at: cdc.gov/coronavirus/2019-ncov/hcp/dental-settings.html. Accessed October 21, 2020.
- Jain M, Mathur A, Mathur A, Mukhi P, Ahire M, Pingal C. Qualitative and quantitative analysis of bacterial aerosols in dental clinical settings: Risk exposure towards dentist, auxiliary staff, and patients. J Family Med Prim Care. 2020;9:1003–1008.
- United States Centers for Disease Control and Prevention. Standard Precautions. Available at: cdc.gov/oralhealth/infectioncontrol/summary-infection-prevention-practices/standard-precautions.html. Accessed October 21, 2020.
- Kharma MY, Alalwani MS, Amer MF, Tarakji B, Aws G. Assessment of the awareness level of dental students toward Middle East Respiratory Syndrome-coronavirus. J Int Soc Prev Community Dent. 2015;5:163–169.
- American Dental Association. Return to Work Interim Guidance Toolkit. Available at: success.ada.org/~/media/CPS/Files/Open%20Files/ADA_Return_to_Work_Toolkit.pdf. Accessed October 21, 2020.
- Chhina S, Singh A, Menon I, Singh R, Sharma A, Aggarwal V. A randomized clinical study for comparative evaluation of aloe vera and 0.2% chlorhexidine gluconate mouthwash efficacy on de-novo plaque formation. J Int Soc Prev Community Dent. 2016;6:251–255.
- Pathan MM, Bhat KG, Joshi VM. Comparative evaluation of the efficacy of a herbal mouthwash and chlorhexidine mouthwash on select periodontal pathogens: An in vitro and ex vivo study. J Indian Soc Periodontol. 2017;21:270–275.
- Ravi Varma Prasad KA, John S, Deepika V, Dwijendra KS, Reddy BR, Chincholi S. Anti-plaque efficacy of herbal and 0.2% chlorhexidine gluconate mouthwash: a comparative study. J Int Oral Health. 2015;7:98–102.
- Cosyn J, Princen K, Miremadi R, Decat E, Vaneechoutte M, Bruyn H. (2013). A double-blind randomized placebo-controlled study on the clinical and microbial effects of an essential oil mouth rinse used by patients in supportive periodontal care. Int J Dent Hyg. 2013;11:53–61.
- Retamal-Valdes B, Soares GM, Stewart B, et al. Effectiveness of a preprocedural mouthwash in reducing bacteria in dental aerosols: randomized clinical trial. Braz Oral Res. 2017;31:1–10.
- Imran E, Khurshid Z, Ahmed AM, et al. Preprocedural use of povidone-iodine mouthwash during dental procedures in the COVID-19 Pandemic. Eur J Dent. 2020;10. Epub.
- Kariwa H, Fujii N, Takashima I. Inactivation of SARS coronavirus by means of povidone-iodine, physical conditions and chemical reagents. Dermatology. 2006;212(Suppl 1):119–123
- Bidra AS, Pelletier JS, Westover JB, Frank S, Brown SM, Tessema B. Rapid in-vitro inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using povidone-iodine oral antiseptic rinse. J Prosthodont. 2020;29:529–533.
- Rashed HT. Evaluation of the effect of hydrogen peroxide as a mouthwash in comparison with chlorhexidine in chronic periodontitis patients: a clinical study. J Int Soc Prev Community Dent. 2016;6:206–212.
- Sethi K, Mamajiwala A, Mahale S, Raut C, Karde P. Comparative evaluation of the chlorhexidine and cinnamon extract as ultrasonic coolant for reduction of bacterial load in dental aerosols. J Indian Soc Periodontol. 2019;23:226–233.
From Dimensions of Dental Hygiene. November 2020;18(10):16-18.