Chlorhexidine Mouthwash: a Friend or Foe for Oral Health?

Over-the-counter mouthwashes containing an antibacterial agent known as chlorhexidine have been widely available for decades [1]. However, much controversy surrounds their usage regarding whether they are good or bad for oral health [2, 3]. On one hand, it is indisputable that these mouth rinses have proven effective because they can eradicate bacteria associated with oral disease, including gum disease and tooth decay [2].  

However, on the other hand, researchers have shone light on the detrimental impact that chlorhexidine mouthwashes can have on the oral cavity because of their unwanted side effects and ability to kill good bacteria, as well as their contribution to a current global crisis known as antimicrobial resistance [1, 2, 3, 4].

The Benefits of Chlorhexidine in Dentistry

Chlorhexidine has been used in dentistry since the 1950s, and this compound can be added to many oral hygiene products, including toothpastes, gels, and most commonly, mouthwashes [2, 3]. The effectiveness of this chemical tends to be measured by its antibacterial effects. When used over the short term, chlorhexidine mouthwash can reduce inflammation associated with gingivitis, and these mouthrinses also have antiplaque properties that can prevent tooth decay [1, 2].  

Additionally, chlorhexidine can reduce the risk of gum disease due to its antimicrobial impact on disease-associated bacteria, particularly the bacterial species known as Fusobacterium nucleatum and Porphyromonas gingivalis [2]. Other positive effects of chlorhexidine mouthwashes include their ability to reduce halitosis and strengthen tooth enamel [4].

The Drawbacks of Chlorhexidine Mouthwash

Unfortunately, everything is not rosy with chlorhexidine, as this chemical has also been shown to harm oral health. For instance, chlorhexidine mouthrinses can increase oral acidity levels, which increases the risk of tooth decay [3].  Chlorhexidine can also cause an imbalance in the oral microbiome, as the chemical is non-selective and targets both good and bad bacterial species [2, 4]. This is particularly true for health-associated nitrate-reducing bacterial species, like Rothia and Neisseria, as eradication of both bacterial types has been linked to an increased risk of systemic disease(s), including cardiovascular disease and diabetes [2].  

Additionally, oral bacteria can become resistant to the effects of chlorhexidine and, consequently, can develop cross-resistance to antibiotics, such as tetracycline and ampicillin [3].  Other adverse side effects include altered taste and teeth staining [4, 5]. 

Exploring Preventive Dentistry

Evidence has shown that chlorhexidine mouthwash can benefit teeth and gums, but this chemical can also be harmful to the oral cavity, particularly when it is used for a long period. Is there anything we can do to limit our reliance on chlorhexidine and protect our oral health? The short answer is yes; we can turn our attention to preventive dentistry!

Preventive dentistry is the best approach to keep the mouth and teeth clean and healthy while limiting our dependence on antibacterial mouthwashes containing chlorhexidine. Taking a preventative approach will lower our lifetime risk of oral disease [6].

Preventive dentistry involves regular brushing twice daily, flossing between teeth, eating a balanced diet with plenty of fruits and vegetables, and regular check-ups at the dentist [7, 8]. A disciplined approach to good oral hygiene reduces the risk of tooth decay and gum disease. It lowers the risk of heart disease and diabetes, as fruits and vegetables promote the growth of good bacteria associated with a decreased risk of systemic disorders! [8, 9, 10].

Summary

Chlorhexidine mouth rinses have been available to the public for many years, and research suggests that this chemical is effective in treating gingivitis. It can also prevent the buildup of dental plaque that causes tooth decay. However, evidence has also shown that chlorhexidine mouthwash can harm oral and systemic health by increasing oral acidity levels and eradicating good bacteria. Preventative dentistry appears to be the best course of action, as developing a good oral hygiene regime will help to keep the mouth clean and healthy whilst reducing the risk of oral and systemic disorders.

 By: Siobhan Moran BSc (Hons) MSc

Edited by: Damilola Elewa