· 6 min
Mouthwash is sold as one more step in daily hygiene, on the same level as the toothbrush and floss. In the clinic the conversation is more nuanced. Some mouthwashes have good evidence for specific goals, such as reducing cavities or controlling plaque during treatment, and others are used out of habit without anyone having said what for. What each type does, and how to use it so it doesn't take away from your toothpaste.
A mouthwash is a liquid solution with one or more active ingredients. Depending on which, it can add fluoride to protect the enamel, reduce the amount of bacterial plaque or lessen bad breath for a while. What no mouthwash does is lift plaque that's already stuck to the teeth or clean well between them. For that you still need brushing and floss or interdental brushes.
It depends on why you use it. If you brush well twice a day with fluoride toothpaste, clean between your teeth and don't get frequent cavities or gum problems, daily mouthwash usually isn't necessary. If you have a specific risk, such as recurring cavities, dry mouth, fixed braces or inflamed gums, a well-chosen mouthwash can add something. The problem comes when a product meant for short periods, like chlorhexidine, is used daily for years, or when mouthwash replaces brushing instead of complementing it.
Chlorhexidine. It's the reference antiseptic in mouthwash research. A Cochrane review of 51 studies confirmed that, added to brushing, it reduces plaque substantially; in people with mild gum inflammation, the reduction in gingivitis was small (James et al., 2017). The same review documented its main drawback: tooth staining with use of four weeks or more, plus taste disturbance and mucosal irritation in some studies. That's why it's used for limited periods and on a dentist's advice.
Fluoride. Fluoride mouthwashes help prevent cavities. In children and adolescents, regular supervised use, mostly in school programmes, was associated with about 27% fewer decayed surfaces in permanent teeth (Marinho et al., 2016). In adults the evidence is thinner, and your dentist may recommend one when cavity risk is high: dry mouth, roots exposed by receding gums or braces. To understand what fluoride does to enamel, see what fluoride is for.
Cetylpyridinium chloride (CPC). It's another antiseptic common in over-the-counter mouthwashes. A meta-analysis of eight trials found that, added to brushing for at least six weeks, it reduced plaque between the teeth and gum inflammation more than a placebo, although results varied a lot between studies (Langa et al., 2021). It's often used by people with mild gingivitis.
Essential oils. Many of these products contain alcohol, which is why some people find them harsh or drying.
Chlorhexidine has its place: after gum or implant surgery, during active periodontal treatment or at times when someone can't brush properly. Outside those contexts, the benefit for the gums is small and the side effects add up over time. The stains come off with a professional cleaning, but they aren't the only effect. In a study of 36 healthy people, seven days of chlorhexidine rinsing substantially changed the makeup of the bacteria in saliva and made it more acidic (Bescos et al., 2020). It's a small, non-randomized study, but it supports using chlorhexidine only when there's a reason and for as long as your dentist advises.
For many people, it's more comfortable. Alcohol can cause a burning sensation and dry the mouth, which especially bothers people who already have dry mouth, sensitive mucosa or are undergoing cancer treatment. On the oral cancer question that comes up often, a meta-analysis found insufficient evidence to say alcohol-containing mouthwashes increase that risk (Aceves Argemí et al., 2020). Choosing an alcohol-free one is reasonable for comfort, and it's the natural choice if you avoid alcohol for any reason.
It's a frequent mistake, and an easy one to fix. After brushing with fluoride toothpaste, it's best to spit out the excess and not rinse with a lot of water, because that washes away some of the fluoride that should stay in contact with your teeth (Davies et al., 2003). The logic is similar for mouthwash. An expert consensus published in the British Dental Journal acknowledges the lack of high-quality evidence on rinsing after brushing and suggests not doing it immediately afterwards (Pitts et al., 2012). In practice, you can use it at another time of day, for example after lunch. Dr. Pablo Atria was quoted in a Flow Space article on a common mouthwash mistake; you can find it in our press section.
There isn't one that's best for everyone. The choice depends on what you need to solve. If your problem is cavities, a fluoride mouthwash. If you have mild gingivitis or plaque that's hard to control, a CPC one can help, always alongside good brushing technique. If you've just had surgery or are in gum treatment, chlorhexidine, for as long as you're told. If you have dry mouth or sensitive mucosa, an alcohol-free one. And if you're looking for a mouthwash for bad breath, it's worth finding out where it comes from first: most of the time it starts on the tongue or the gums, as we explain in bad breath: causes and treatment.
No mouthwash replaces proper brushing or cleaning between the teeth, because stuck plaque can only be removed mechanically. Nor does it replace a professional dental cleaning: once tartar has mineralized, no liquid dissolves it. If you use mouthwash every day, it's worth mentioning at your next check-up to confirm the type you use still makes sense for you.
If this article left you with questions, explore the related services or book an evaluation at AS Odontología Digital in Vitacura.
Book an evaluationIt depends on the type and why you use it. If you brush well with fluoride toothpaste and clean between your teeth, daily mouthwash usually isn't necessary. If you have frequent cavities, dry mouth, braces or inflamed gums, a well-chosen mouthwash, such as fluoride or CPC, can add something. Chlorhexidine, on the other hand, is used for limited periods on a dentist's advice.
The evidence is limited, but experts suggest not rinsing with a lot of water or mouthwash right after brushing, so you don't dilute the fluoride from the toothpaste. Spit out the excess and use mouthwash at another time of day, for example after lunch. If your dentist prescribed a specific mouthwash, follow their instructions.
No. No mouthwash lifts plaque stuck to the teeth or cleans well between them. It can complement hygiene in specific cases, but brushing and floss or interdental brushes remain the foundation.
Its main side effect is surface staining: with use of four weeks or more it increases markedly, and it can also alter taste or irritate the mucosa. The stains come off with a professional cleaning. That's why it's used for limited periods, as your dentist advises.
For many people it's more comfortable, because alcohol can burn and dry the mouth. It's especially worth it if you have dry mouth or sensitive mucosa. On oral cancer, a meta-analysis found insufficient evidence to say alcohol-containing mouthwashes increase the risk.
It depends on what you need: fluoride if the problem is cavities, CPC for mild gingivitis or plaque that's hard to control, chlorhexidine for a limited time after surgery or during gum treatment, and alcohol-free if you have dry mouth. Your dentist can guide you based on your case.
A mouthwash can reduce bad breath for a few hours, but it doesn't fix the cause. Most of the time it starts on the tongue or the gums, and it's treated with tongue cleaning, good hygiene and, if there's gingivitis or periodontitis, gum treatment. If it persists, an evaluation is worth it.
Written by
