If you've started drinking cold water out of one side of your mouth, this one's for you. That short, sharp twinge from cold air, ice cream or a sweet cup of tea is one of the most common things people hope a toothpaste will fix, and for anyone who'd rather avoid fluoride our answer is the same every time: hydroxyapatite, and specifically Biorepair Plus Sensitive Teeth at 24%. Here's why.
What's behind the twinge
Under your enamel, and under the gum at the root, sits dentine. It's threaded with microscopic channels that run towards the nerve. While dentine is covered, those channels are sealed off; once it's exposed, cold and sweetness travel down them and you feel it. Dentine gets exposed in ordinary ways: gums receding, enamel worn by acidic food and drink, years of brushing too hard, grinding. It creeps up slowly, which is why so many people put up with it for years.
Sensitivity toothpastes work in one of two ways. Some calm the nerve. Others block the channels, and hydroxyapatite is one of those, blocking them with the same mineral your enamel is made of.
Why hydroxyapatite is our first choice
The evidence is unusually strong for a toothpaste ingredient. Limeback, Enax and Meyer's 2023 meta-analysis pooled 44 clinical trials of hydroxyapatite for sensitive teeth, more than half of them rated high quality. Hydroxyapatite reduced sensitivity significantly more than placebo and significantly more than fluoride, and about as well as the other established sensitivity ingredients.
Biorepair Plus is part of that evidence. In an eight-week double-blind randomised trial it cut air-blast sensitivity scores by 46%, against 29% for a potassium nitrate and fluoride sensitivity toothpaste, and in a three-day trial it eased sensitivity alongside two well-known sensitivity toothpastes. The reviewers graded both trials high quality.
Results vary from person to person, those two trials used a 30% version of Biorepair's ingredient rather than today's 24% tube, and two of the review's three authors work for a German hydroxyapatite toothpaste maker; that is the whole of the fine print.
What about the big-name sensitivity toothpastes?
They work. Potassium nitrate, potassium citrate and stannous fluoride are all recognised sensitivity ingredients. The catch, if you're avoiding fluoride, is that the big names usually come with fluoride in the tube, and stannous fluoride is fluoride by definition. Hydroxyapatite gives you a channel-blocking toothpaste without it, and in the 44-trial meta-analysis it held its own against those established ingredients.
Why Biorepair Plus Sensitive Teeth
It has the highest concentration in the Biorepair Plus range: 240 mg/g, or 24%, of microRepair®, Biorepair's zinc-substituted carbonate hydroxyapatite. It's fluoride-free. Biorepair publishes that figure rather than hiding behind "with minerals", and it reports relief in 30 seconds on average from its own study of 100 people. At £6.99 for 75 ml, using it twice a day indefinitely is realistic, which matters, because sensitivity toothpaste works for as long as you keep using it.
No twinges, and you simply want fluoride-free? Biorepair Plus Total Protection is the same price with 20% microRepair®, and our Sensitive Teeth vs Total Protection comparison explains the difference.
Help it along
Ease off the pressure. Brushing too hard is one of the most common reasons dentine gets exposed in the first place, and almost everyone believes they brush gently. The Oral-B iO9 shows you the moment you press too hard, and its Sensitive mode gives a gentler feel while your teeth settle down.
Don't brush straight after acid. Fizzy drinks, citrus, wine and vinegary dressings soften enamel for a while. Rinse with water and wait before you brush.
Spit, don't rinse. Rinsing straight after brushing washes away the paste you've just put there.
Be patient. Give it six to eight weeks of twice-daily use. Judging a sensitivity toothpaste after four days tells you about its flavour.
When it isn't sensitivity
A sensitivity toothpaste is for the quick twinge across several teeth that fades within seconds. Pain in one tooth, pain that lingers or throbs, pain that arrives suddenly, swelling, or a tooth that's cracked or has lost a filling is a different problem, and it needs a dentist to look at it rather than a new tube.
Why buy from Onyx
Biorepair Plus Sensitive Teeth was chosen by the practising dentists behind Onyx, and it's the first tube we suggest for sensitive teeth without fluoride. It's £6.99 on its own, or £6.29 with Subscribe and Save 10%, delivered every four or eight weeks. You'll find it in our fluoride-free and hydroxyapatite toothpaste collections, and it's the toothpaste in our Complete Care Bundle, Sensitive Teeth: the iO9, four iO Ultimate Clean heads and a tube for £180, £11.98 less than buying separately (see all our bundles). Order before 4pm for same-day dispatch, delivery is free on UK orders over £50, unopened items can come back within 30 days, and if you have a question about which tube suits you, email hello@onyx-dental.co.uk and one of our dentists will reply.
Sources
- Limeback, Enax and Meyer: meta-analysis of 44 trials on sensitivity, Biomimetics (2023)
- Orsini and colleagues: eight-week trial of a zinc-carbonate hydroxyapatite toothpaste, Journal of Clinical Periodontology (2010)
- Orsini and colleagues: three-day trial of three sensitivity toothpastes, Journal of Periodontology (2013)
- Oral Health Foundation: sensitive teeth
- Biorepair: microRepair® concentrations
- Oral-B UK: iO9 Black Onyx