Chlorhexidine is a common mouthwash ingredient known to help reduce harmful of bacteria in the mouth.
However, new research from the University of Plymouth’s Faculty of Health suggests that chlorhexidine could increase the risk of tooth damage.
Given the circumstances, it is worth taking a closer look at the potential benefits and drawbacks of this commonly-used mouthwash.
What is Chlorhexidine?
Chlorhexidine (also known by its generic name, Chlorhexidine gluconate), is an antimicrobial oral rinse that, when coupled with regular tooth brushing and flossing, can be used to treat gingivitis. Chlorhexidine reduces the amount and diversity of bacteria in the mouth, which helps alleviate swelling, redness and bleeding of the gums caused by gingivitis.
Chlorhexidine is generally prescribed to patients for twice-daily use: once after breakfast and again right before bedtime. Like other kinds of mouthwash, patients are instructed to measure out about a half-ounce (15 milliliters) of the solution, swish it in their mouths for about 30 seconds, and then spit it out. Prescription mouthwashes with chlorhexidine have been widely available for more than 30 years.
However, mouthwash containing chlorhexidine has been shown to significantly increase the abundance of lactate-producing bacteria that lowers the saliva pH, which could increase the risk of tooth damage.
Why Oral Bacteria is Not Always a Bad Thing
Researchers at the University of Plymouth carried out a trial on the effects of mouthwash containing chlorhexidine, giving placebo mouthwash to subjects for a few days, followed by seven days of mouthwash containing chlorhexidine.
By the end of each period, the researchers analyzed the microbiome and pH levels in each person. They also looked at things like lactate, how well acids were neutralised (also known as saliva buffering capacity), as well as other factors related to oral health.
The research found that using chlorhexidine mouthwash led to an increase in acidity. More research is needed to determine whether this necessarily means an increased risk of oral diseases.
According to Dr. Zoe Brookes, co-author of the study and lecturer at the University of Plymouth's Peninsula Dental School, dental clinicians need more information about how mouthwashes can alter the balance of oral bacteria to in order to prescribe them correctly.
“This paper is an important first step in achieving this,” says Dr. Brooks.
Co-author Dr. Louise Belfield adds, “We have significantly underestimated the complexity of the oral microbiome and the importance of oral bacteria in the past. Traditionally the view has been that bacteria are bad and cause diseases. But we now know that the majority of bacteria – whether in the mouth or the gut – are essential for sustaining human health.”
As you well know, the mouth is swimming with many different microorganisms, most of which are beneficial and essential for maintaining normal physiology of the oral cavity.
The authors believe this is the first study to examine the impact of 7-day use of chlorhexidine on the oral microbiome – important insight, given the renewed popularity of this mouthwash in the current climate.
More information is still needed to determine how the chemical works on viruses, however, some suggest that chlorhexidine kills COVID-19 since it kills other viruses, like H5N1 (bird flu), H3N2 (influenza virus), and H1N1 (swine flu) and thus could help reduce the new infection rates among healthy people (or help to flatten the curve).