Your Diet Coke Is Doing More Damage to Your Teeth Than You Think

In the last article I talked about how we rebuild worn-down teeth with bonded composite at BDS Dental, and I promised I’d get into why we’re seeing more of this kind of damage than we used to. So here we are.

Tooth wear is on the rise in this country, and there are a few reasons for it. People are living longer, and they’re holding on to their own teeth for longer — which is great news in itself, but it also means teeth are taking decades more wear and tear than they did a couple of generations ago. Stress is a factor too: people grind their teeth when they’re stressed, and most patients I see have more stress in their lives than they used to. But the single biggest preventable driver I see, day in and day out in the chair, is what people are drinking.

I want to spend most of this article on that — because if you take one habit-change away from this whole series, this would be the one I’d choose for you.

Cola, and the thing nobody tells you about it

There’s the obvious problem with cola, which is the sugar. Full-fat Coke has a lot of sugar in it, and sugar feeds the bacteria that cause decay. Almost everyone knows that one.

But the less obvious problem — and in many ways the bigger one — is the acid.

All fizzy drinks contain carbonic acid. That’s what gives them the fizz. That alone is fairly acidic and will cause erosion — even fizzy water such as San Pellegrino. But colas, specifically, have something else added: phosphoric acid. It’s added to give them that sharp, slightly tangy kick. And phosphoric acid is, to put it bluntly, aggressive stuff.

Phosphoric acid has, globally, two main industrial uses. The first is in cola — Coke, Pepsi, the supermarket own-brands, all of them. The second is in car batteries. The same compound. People drink it by the gallon and don’t think anything of it.

That’s true of every cola product. Coca-Cola. Pepsi. The own-brand stuff. Full-fat, sugar-free, diet, zero — all of them. The phosphoric acid is there for the taste, regardless of whether the sugar is.

The Diet Coke surprise

Here’s the bit that catches most patients out. Diet Coke, Coke Zero, Pepsi Max — the “healthier” options people switch to when they’re trying to cut down on sugar — actually contain slightly more phosphoric acid than regular Coke. The reason is straightforward: take the sugar out and the drink needs more acid to keep the taste recognisable. So if you’ve moved from Coke to Diet Coke thinking you’ve done your teeth a favour, the picture is more complicated than that.

You’ve cut out the sugar problem, which is real, and that will help slow your rate of decay. But you haven’t cut out the acid problem — and on some measures, you’ve made it slightly worse.

I’ll be straight: I think it’s a diabolical product. I was once asked to take part in a debate on whether Coca-Cola was, on balance, doing more damage to global health than smoking. The answer is probably no — it’s not quite that bad. But it’s not as far behind as you might hope. As smoking rates have come down over the years, cola consumption has gone up, and the picture is moving in the wrong direction, not the right one.

What acid actually does to your teeth

When you drink a cola, the acid washes over your teeth and softens the enamel. Enamel, in its healthy state, is glassy — strong, intact, very resistant to wear. Acid softens it. While the enamel is in that softened state, anything mechanical — brushing, grinding, even chewing — wears it away faster than it would otherwise. Over time, you lose tooth structure that doesn’t grow back.

Repeated acid attacks throughout the day, with the teeth never getting a proper chance to recover between them, is what causes acid erosion. It tends to show up first on the inside or biting surfaces of the front teeth — they become thinner, more translucent, sometimes a bit cupped or hollowed out. By the time it’s visible to a patient in the mirror, there’s already been significant damage.

Combine that with someone who clenches or grinds — and most of the patients I see have at least some of that, especially under stress — and you have a tooth that is being chemically softened during the day and then mechanically worn down on top of it by night.

It’s not just fizzy drinks

I don’t want to single out cola as if it’s the only culprit. As more people have become health-conscious, two other things have started showing up in the chair.

The first is people drinking lots of citrus — fresh lemon water first thing in the morning, citrus-heavy juices, sliced lemon in everything. The acid in citrus is not as aggressive as the acid in cola, but it’s still acid, and the habits people build around it tend to mean lots of small acid hits across the day, which is exactly the pattern enamel doesn’t recover from.

The second is salads dressed in vinaigrette every day. Again, the dressing is acidic, and when it’s a daily habit it adds up. I’m not going to tell people to stop eating salad. But it’s worth being aware that the things we tend to think of as the healthy choices are not necessarily neutral for our teeth.

What you can do without giving everything up

I’m not in the business of telling people they can never have a Diet Coke again. People are going to drink what they’re going to drink, and most patients aren’t going to make a major lifestyle change on the back of one dental appointment. But it is worth being aware of what these drinks — and the broader pattern of small acid hits across the day from citrus, vinaigrettes and the like — are doing to enamel that doesn’t grow back.

There’s quite a bit of practical advice we go through with patients in the chair about how to minimise the impact: when in the day you have these drinks, how to give your teeth a chance to recover between acid exposures, and how to look after your enamel afterwards. It’s the kind of conversation that’s much better had face-to-face, looking at your own teeth and your own habits, than as a generic list on a blog. So if you’re a regular cola or citrus drinker and you’re worried about it, that’s exactly the sort of thing to bring up at your next check-up. We’ll talk you through it.

There is, however, one really important piece of advice I can give here for free — and it’s completely counter-intuitive. Do not brush your teeth immediately after having something acidic, and especially not after being sick.

Remember how acid turns glassy enamel chalky? All toothbrushes are mildly abrasive. On healthy, pH-neutral enamel that does no harm — but in that softened, acid-weakened state, brushing can scrub healthy enamel away.

The best advice is to rinse your mouth with water or a fluoride mouthwash and wait at least twenty minutes before you brush.

Acid that comes from inside the body

We’ve covered what not to eat and drink, but acid can also come from inside the body. The list below isn’t exhaustive, but these are the things we always look out for when we take and update a patient’s medical history.

• Gastro-oesophageal reflux disease (GERD): chronic heartburn and reflux push acidic stomach contents up into the mouth, often during sleep. Stomach acid can be even more acidic than cola.
• Eating disorders: conditions such as bulimia and anorexia can repeatedly expose the teeth to stomach acid through vomiting.
• Chronic vomiting: long-term vomiting — from alcohol misuse, persistent illness, or even pregnancy (morning sickness) — significantly increases the risk of erosion.
• Dry mouth: saliva is roughly neutral, so it isn’t an acid source itself, but a lack of it severely limits the mouth’s ability to neutralise acid and re-mineralise enamel, which makes erosion worse.

What we can do once damage has happened

If you’ve already lost a meaningful amount of tooth structure — chipped edges on the front teeth, shorter teeth than you used to have, teeth that look more translucent or hollowed than they should — that’s where the technique I wrote about in the last article comes in. We can rebuild what’s been lost with bonded composite, usually without drilling, often for a fraction of what crowns would cost. The Dahl effect lets us restore the bite to its proper height without touching the back teeth at all.

But — and this is the important part — none of that fixes the underlying habit. If we rebuild your worn teeth and you carry on with the same pattern of cola, citrus, and grinding, the new material will hold up better than your enamel did, but the issue hasn’t gone away. So whenever we treat wear at BDS, the conversation about diet and habits is part of the treatment, not an add-on.

This is also why I push the partnership idea I wrote about in part two of this series so hard. Dentistry alone isn’t the solution to acid erosion. The solution is dentistry plus changes in the habits causing it — and the bit that’s in the patient’s hands is, often, the bit that matters most over the long run.

If you can already see the damage

If you can already see your front teeth getting thinner, more translucent, or chipped along the edges — please don’t wait. The earlier we catch acid erosion, the more conservatively we can address it. Caught early enough, the conversation might just be about the habits driving it. Caught later, we’re looking at rebuilding with composite, which we can absolutely do — but I’d much rather help you hold onto the enamel you’ve got than rebuild what’s been lost.

Coming up

The final article in this series is going to deal with a question I get asked more and more often — what to do when patients come in wanting cosmetic dental work they’ve seen on Instagram. Veneers. The very white, very even, very uniform look. How we handle those conversations honestly, where there’s room for genuinely minimally invasive cosmetic work, and the patients I won’t take on for cosmetic dentistry. That’s part five.

Dr Ellie Bergin is a partner at BDS Dental and a clinical teacher at King’s College London. If you’ve noticed your front teeth chipping or thinning, or you’d like to talk through whether wear restoration is right for you, contact the practice here. You can also book online here.