Mouthwashes: chlorhexidine is not a product for continuous daily use

Mouthwash is the aid patients buy most readily and use for longer than they should, because rinsing is easy and gives an immediate sense of cleanliness.

The first point to make clear is that no mouthwash removes mature biofilm. Antiseptic agents act on superficial bacteria and on forming plaque, not on an organised deposit.

Hence the rule that bears repeating: mouthwash is an adjunct, never a substitute for the toothbrush and interdental aids. A patient who rinses instead of brushing makes their situation worse.

Chlorhexidine remains the reference for antiplaque efficacy, with the broadest documentation. At therapeutic concentrations it markedly reduces bacterial load and gingival inflammation.

It has side effects, however, that limit prolonged use. Brown staining of teeth and tongue is the most visible, appearing within a few weeks in many patients.

Taste alteration is what most often leads to abandonment, and supragingival calculus tends to increase. None of these effects is serious, but together they make the product unsuitable for continuous use.

The correct indications are short, defined courses: after surgery, during acute gingivitis, when mechanical cleaning is temporarily impossible.

Prescribing it with an end date works better than recommending it generically, because otherwise the patient continues until the bottle runs out and then buys another.

One practical detail that affects efficacy: chlorhexidine is inactivated by the anionic surfactants in toothpaste. Rinsing immediately after brushing reduces the effect, and the two should be separated by at least half an hour.

Essential oil mouthwashes have good documentation for prolonged daily use, without staining. They are the more sensible choice when an antiseptic is needed long-term.

Cetylpyridinium chloride has intermediate efficacy and fewer side effects, and is very common in over-the-counter products. Concentration and formulation greatly influence the result.

Fluoride mouthwashes have a different and complementary function: they act not on bacteria but on remineralisation. They are indicated in high caries-risk patients, in addition to toothpaste.

In summary: no mouthwash replaces mechanical removal, chlorhexidine is prescribed in courses with an end date, essential oils are the choice for prolonged use, and chlorhexidine must be separated from toothpaste.