A glass of water and soft toothbrush on a bathroom shelf

Quick answer

Persistent dry mouth (xerostomia) is usually caused by medications (blood pressure tablets, antidepressants, antihistamines and dozens more, with effects stacking), mouth breathing, dehydration, or medical conditions and treatments. It matters because saliva neutralises acid and repairs enamel; without it, decay accelerates dramatically, especially at the gumline. Relief: sip water constantly, chew sugar-free gum, use saliva-substitute gels and sprays, run a humidifier at night, and limit caffeine and alcohol. Protection: high-fluoride toothpaste, no sipping of sugary or acidic drinks, and more frequent dental checks.

Why it wrecks teeth so fast

Every sip and snack drops the mouth's pH into acid territory; saliva buffers it back and redeposits minerals into enamel, dozens of times a day. Remove the saliva and every acid dip runs long and unrepaired. The result is a distinctive, fast-moving decay pattern along the gumlines and around old fillings, which is why dentists take dry mouth more seriously than patients expect, and why 'my teeth suddenly fell apart' stories so often start with a new medication the year before.

The usual causes

  • Medications, by far the biggest: many blood-pressure drugs, antidepressants, antihistamines, bladder medications and strong pain relievers list it, and the effect stacks with each added script. Never stop a medication over it; the answer is managing the mouth, and sometimes a GP conversation about alternatives, easy when the GP is down the corridor
  • Mouth breathing and snoring: the overnight version, announced by waking with a desert mouth; it pairs with our grinding and kids' airway conversations
  • Dehydration, caffeine and alcohol, including alcohol-based mouthwashes, which dry the mouth they claim to freshen
  • Medical causes and treatments: diabetes, Sjögren's syndrome, and head-and-neck radiotherapy, each deserving coordinated dental and medical care

Relief and protection that actually work

  • Water within reach all day; small frequent sips beat occasional gulps
  • Sugar-free gum after meals: chewing is the strongest natural saliva trigger
  • Saliva-substitute gels and sprays from the pharmacy, especially before sleep; a bedroom humidifier helps mouth breathers
  • High-fluoride toothpaste (prescription-strength on our recommendation), spit don't rinse
  • Ruthlessness about sipped sugary and acidic drinks: with no saliva to clean up, a bottle of soft drink nursed across an afternoon is the single most destructive habit possible
  • Shorter intervals between check-ups while the risk is elevated; catching gumline decay early is cheap
Tell us about dry mouth even though it seems minor; it changes your risk profile and we'll adjust your prevention plan (fluoride strength, product suggestions, recall interval) accordingly. Tell the GP too: it's sometimes the clue to an undiagnosed cause.