Medication, saliva and dry mouth

Saliva is rarely mentioned when dental care is discussed, and yet it does the greater part of the work. It rinses away residues and bacteria, neutralises acids within a few minutes, supplies calcium and phosphate for re-deposition into the enamel, contains antibacterial proteins and keeps the mucosa supple.

If it fails, all of that fails. A dry mouth is therefore not merely unpleasant; it is a solid risk factor for caries — and for a particularly fast-advancing form of it.

How you notice it

• a sticky feeling, the tongue sticks to the palate
• difficulty speaking for longer periods and swallowing dry food
• a burning tongue, reddened or cracked mucosa
• cracks at the corners of the mouth
• an altered sense of taste
• bad breath
• dentures that suddenly fit badly or chafe
• new caries sites in a short time, often at the tooth necks

The most common cause is medication

Several hundred active substances can reduce the flow of saliva. Particularly often:

• diuretics and blood pressure tablets
• antidepressants and neuroleptics
• antihistamines for allergies
• drugs for an irritable bladder and incontinence
• strong painkillers from the opioid group
• drugs for nausea and for Parkinson's
• decongestant nasal sprays with longer use

The effect adds up: anyone taking several such medicines at the same time is markedly more affected. That explains why dry mouth is so widespread in later life — the cause is not age itself but the number of preparations.

Further causes are radiotherapy in the head and neck area, Sjögren's syndrome, poorly controlled diabetes, lack of fluid, constant mouth breathing and alcohol.

What helps

• Drink water spread across the day, in small amounts. A bottle within reach works more reliably than a resolution.
• Chew sugar-free gum, preferably with xylitol. Chewing is the strongest natural stimulus for the flow of saliva.
• Saliva substitutes as a spray or gel, especially for the night.
• Intensive fluoridation: fluoride toothpaste, plus a gel once a week, and where the risk is high a highly concentrated toothpaste on prescription.
• Shorter intervals between check-ups and cleanings. Caries arises faster here than otherwise.
• Look out for sugar-free products — including in lozenges for the dry mouth itself.
• Limit alcohol and caffeine, both dry further. Avoid mouthwashes containing alcohol.
• Humidify the air, especially in the bedroom.

And the most important point: talk to the doctor who prescribed the medicine. Sometimes there is a preparation within the same group with less of a drying effect; sometimes the time of taking it can be moved. Medicines are not stopped on your own initiative because of this — but it is worth asking the question, and it is rarely asked.

Root caries: the typical consequence

With a dry mouth, caries arises preferentially at the tooth neck, where the gum has receded. This surface has no enamel; it is attacked at a higher pH than the crown of the tooth and advances considerably faster. Without the buffering effect of saliva, the most important counterpart is missing.

Anyone with exposed tooth necks and a dry mouth belongs in short check-up intervals and needs fluoride in a higher concentration. That is not excessive caution but the answer to a genuinely increased risk.