Mouthwash: When It Helps and When It Does Not

Chlorhexidine is for short-term use: NHS guidance says its dental treatments are usually used for up to 4 weeks, and 4 weeks for gum disease.

An antiseptic, chlorhexidine coats the teeth and gums to help stop plaque building up, the NHS explains. Used for too long, it may not work as well. Follow the pack instructions or, if prescribed, your doctor, dentist or pharmacist's advice.

UK guidance, Delivering Better Oral Health (DBOH), says the available evidence suggests high certainty that chlorhexidine rinse reduces plaque and gingivitis. A 2017 Cochrane review of 51 trials, with at least 4 weeks' use alongside brushing and cleaning, found a large plaque reduction and, in mild inflammation, a gingivitis reduction not considered clinically relevant (both high-quality evidence), and insufficient evidence for moderate or severe inflammation.

Yes. Rinsing with chlorhexidine for 4 weeks or longer causes extrinsic tooth staining, the 2017 Cochrane review found. Stained teeth and tongue colour changes go away when you stop using chlorhexidine, the NHS says; for stained teeth, it advises brushing regularly.

DBOH lists adverse effects of longer-term use including tooth staining, taste disturbance, a burning feeling or burning tongue, and soreness, irritation, mild peeling, ulcers or erosions of the mouth lining, and so advises short-term use. Short bursts of mild burning, tingling or a strange taste sometimes happen at first and improve as you keep using chlorhexidine; if it does not go away, talk to a doctor or pharmacist, as it may be an allergy, the NHS says.

If your mouth is sore or irritated, stop and speak to a dentist, doctor or pharmacist, or call 111; if skin inside it peels, stop and speak to your dentist or doctor. Ask a pharmacist, dentist or doctor if a side effect persists.

NHS guidance gives these actions; if you do not have a dentist or cannot get an emergency appointment, call 111 or visit 111 online:

• Gums that bleed when you brush your teeth or eat hard foods, gums that are painful and swollen, bad breath, or a child with sore, bleeding gums: see a dentist.
• Gum disease, in you or your child, with other symptoms such as very sore and swollen gums, teeth becoming loose or falling out, ulcers or red patches in your mouth, or a lump in your mouth or on your lip: ask for an urgent dentist appointment.
• Toothache that lasts more than 2 days, does not go away with painkillers, or comes with a high temperature, pain when you bite, red gums, a bad taste or a swollen cheek or jaw: see a dentist.
• Toothache with swelling around your eye or neck, or swelling in your mouth or neck that makes it difficult to breathe, swallow or speak: go to A&E, but do not drive; ask someone to drive you or call 999 and ask for an ambulance.

BPE screening, six-point charting, non-surgical periodontal therapy, desensitising treatment, halitosis assessment and advanced gum disease treatment have no line on the fee list. Nor do gum surgery or gum grafting.