Millions of people routinely use mouthwash as a part of their daily oral hygiene, but dental professionals are increasingly warning that this practice may be unnecessary for most and could even be detrimental to health. The habit, reportedly undertaken by 60 percent of people at least weekly, is being questioned for its efficacy and potential side effects.
While mouthwash is often perceived as essential for eliminating bacteria, combating bad breath, and preventing tooth decay, researchers suggest there is limited evidence that it is more effective than regular tooth brushing for these issues. Instead, some studies indicate that mouthwash could disrupt the delicate balance of bacteria in the mouth, potentially impacting blood pressure and even increasing cancer risk.
The Role of Oral Microbiome
The mouth is home to billions of bacteria, many of which play a crucial role in maintaining oral and overall health. Therapeutic mouthwashes, designed to kill bacteria, indiscriminately eliminate both harmful and beneficial bacteria. This disruption can have unintended consequences.
One significant concern is the impact on blood pressure regulation. Bacteria in the mouth play a role in converting nitrates from food into nitric oxide, a compound essential for dilating blood vessels and lowering blood pressure. Research, including a 2020 trial involving 36 healthy adults, observed a significant shift in the oral microbiome and a drop in bacteria responsible for blood pressure management after a week of using therapeutic mouthwash. Another small study of 19 volunteers noted a small increase in blood pressure and reduced nitrite levels after using mouthwash for seven days. A separate trial with 15 hypertensive adults found that three days of mouthwash use further increased their blood pressure.
These studies often involved mouthwashes containing chlorhexidine, a strong antiseptic typically recommended for short-term use for specific dental conditions. Some experts worry that the link between higher blood pressure and increased risk of heart disease also makes regular mouthwash use a potential concern for cardiovascular health.
Potential Cancer Risk
There is also evidence suggesting a link between mouthwash use and an increased risk of cancer. Many mouthwashes contain up to 27 percent alcohol, a known carcinogen. A 2014 study by the International Agency for Research on Cancer linked mouthwash use to oral cancer, but primarily in individuals using it more than three times daily.
Addressing Bad Breath
For those using mouthwash primarily to combat bad breath, experts caution that it may only mask the symptom without addressing the underlying cause. Conditions like gum disease, which can cause persistent bad breath, require specific treatment. Using mouthwash in such cases is likened to using an air freshener without fixing the source of the odor.
Recommended Oral Hygiene Practices
Dentists recommend brushing teeth at least twice a day with fluoride toothpaste. The mechanical action of brushing effectively removes bacteria and food particles, while fluoride strengthens tooth enamel. Unlike mouthwash, the foam produced during brushing helps fluoride adhere more effectively to teeth.
While occasional use of mouthwash, such as once a month or even once a week, is unlikely to cause significant harm, daily, long-term use is what experts warn against. Some oral medicine experts keep mouthwash readily available but do not use it daily, emphasizing moderation and awareness of its potential effects.
Mouthwash with up to 27 percent alcohol can be a known carcinogen.