Preventing the transmission of harmful germs

cpc mouthwashes to avoid cross contaminationNick Claydon takes a look at the research behind CPC mouthwashes and virus elimination in the dental practice.

With the advent of SARS-CoV-2 (COVID-19) pandemic, who could disagree that keeping patients and practitioners safe from harmful germs in the workplace is of paramount importance?

Even with the vaccination programme now underway, new strains of the virus coupled with rising infection rates mean the risk to public health remains high. Therefore, what practical steps can we take now to improve safety in the dental practice?

There is growing clinical evidence (Sreenivasan et al, 2012; Meister et al, 2020; Green et al, 2020) that points to the potential virucidal effects of some mouthwashes that contain Cetylpyridinium Chloride (CPC).

In November 2020, preliminary in vitro results from an independent study conducted by Cardiff University concluded that certain mouthwashes containing Cetylpyridinium Chloride (CPC) completely inactivated the SARS-CoV-2 (COVID-19) virus within a 30-second exposure in a lab setting. And therefore may be effective as a preventative measure against transmission of harmful germs.

Here Dr Nick Claydon, specialist periodontologist, will discuss the relevance of these findings for dental practitioners. As well as the overall importance of oral hygiene during the global pandemic.

What is the significance of a good oral hygiene routine in a global pandemic?

Messages to reinforce good oral hygiene are appropriate at all times. The current pandemic provides added focus of the importance of oral health in particular. And general health overall.

Periodontal disease, for example, is the sixth most common disease in mankind (Kassebaum et al, 2014).

In its severe form it affects more than 10% of the population. And more than three quarters of the resulting damage is directly attributed to the body’s immune response to the presence of dental plaque at the gingival margin.

Risk factors to the diseases include heredity, poor oral hygiene, smoking and some underlying medical conditions such as poorly controlled diabetes.

The impact of these diseases is reduced chewing function, aesthetic impairment, tooth loss, social inequality, reduced quality of life and a significant impact on public health finances.

What is CPC and what are the benefits of using a CPC-based mouthwash generally?

The rationale for self-directed oral hygiene is that it is the most significant risk factor that is modifiable. High-quality plaque removal contributes not only to improvements in the health of the oral tissues, but it also positively impacts systemic wellbeing.

Plaque removal and the removal of bacteria is primarily achieved through mechanical disruption of dental biofilm with toothbrushing. The process is improved by conjunctional use of antiseptic toothpastes. We can derive additional benefit from the adjunctive use of antiseptic mouth rinses in individual cases.

Cetylpyridinium Chloride (CPC) is a quaternary ammonium, surface-active agent with cationic properties. It has a broad spectrum activity. It works by disrupting the bacterial cell membrane leading to leakage of the contents. And it was first described as having clinical anti-plaque and anticalculus effect in 1962.

When used in a mouth rinse formulation as part of a programme of oral care, CPC is considered by systematic review and meta-analysis (Serrano et al, 2015) to deliver a statistically significant additional benefit in reducing plaque accumulation and gingival inflammation.

Based on the research to date, to what extent should a CPC-based mouthwash be used in practice as a potential preventive measure against the transmission of harmful germs?

This is a really good question. It allows us to explore aspects of cross infection in dentistry not previously addressed. Although I would urge caution at the extrapolation of research data of an oral health product designed primarily to evaluate plaque accumulation to that of minimising cross infection risk.

Recent interest in viral infections points to the modes of transmission. Either directly ie from coughing/sneezing from the patient. Or through the generation of aerosols as a result of treatment from dental health professionals.

We cannot easily mitigate either of these events. Although we could in theory reduce the risks of contamination by minimising the viral load present in the oropharynx. As well as addressing PPE and air quality.

The one reassuring advantage from early studies and systematic reviews (Serrano et al, 2015) is that we are able to confirm CPC product safety together with oral health benefit in vivo.

Based on the findings of this independent study, is it enough just to use any CPC-based mouthwash?

The results from studies that take place in the laboratory are usually the first step in helping to prove a product’s efficacy.

Laboratory studies are an appropriate way to sift the most promising products. And to warrant the further investment of time and finance in clinical studies to look at safety and efficacy.

These should ideally be well designed randomised controlled studies of an appropriate duration and numbers of participants. Studies that specifically investigate the clinical outcome as a result of a particular intervention.

Currently, CPC-based mouth rinses have proven anti-plaque and anti-gingivitis benefit when used as adjuncts to home toothbrushing.

The Cardiff University laboratory study shows that certain CPC mouthwashes were also effective at completely eradicating SARS-CoV-2. However, as this was in a lab setting, it warrants more research.

And finally, what further research would you like to see in this area of CPC-based mouthwashes and COVID-19?

At the moment, there is little peer-reviewed evidence that using a mouthwash reduces transmission in a clinical environment.

Given the antiviral potential demonstrated in vitro (O’Donnell et al, 2020; Green et al, 2020), it is not unreasonable to conduct further research in vivo to evaluate the impact of CPC pre (and/or post) treatment mouthwashes.

This represents an exciting avenue of research. In vivo confirmation of antiviral activity of CPC-related products would enable the recommendation of a single mouthwash. At least preoperatively, as part of any clinical procedure to reduce risk of transmission.

This would represent a small, amenable and inexpensive adjustment to standard treatment protocol. In return for greater safety for patient and dental healthcare professionals. As well as confidence in the profession overall.

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