What actually ruins teeth?

Ten factors, some obvious and some not. The ones worth paying most attention to are those marked below as irreversible — acid wear and gum recession cannot be undone, only prevented.

1. Sugar

It is common knowledge that sugar contributes to tooth decay. What is less well known: naturally occurring sugars — in honey and fruit — are just as detrimental as refined sugar.

Frequency of intake is crucial. Ten exposures across a day does far more damage than the same quantity eaten at once. Reduce consumption, and keep up brushing and flossing.

More on the mechanism in how does sugar affect your dental health?, sugar: what does it do to your teeth? and how does your diet affect your teeth?; the decay process itself is in how does tooth decay develop? and the stages of dental decay.

2. Acid — irreversible

Dentists are increasingly seeing acid wear, or erosion. Again, frequency of exposure matters most.

Sources include diet — lemon juice, wine, soft drink, and sparkling water, which is acidic and often overlooked — and biological factors, usually acid reflux. Is soda water bad for your teeth? works through the sparkling-water case with the actual pH numbers, and are sugar free soft drinks better for my teeth than regular soft drinks? deals with the diet-drink assumption. Sports drinks are among the worst of all: what are sports drinks really doing to your teeth?.

Acid wear cannot be reversed, because lost enamel cannot be rebuilt. Adding insult to injury, an acidic mouth is an environment in which oral bacteria thrive, leading to further problems. See what is dental erosion and how is it addressed?, I’ve heard a lot about acid wear — what is this and how can I avoid it? and how does acidic food affect your teeth?. What can still be done is covered in what can I do to strengthen my teeth?.

3. Grinding

Common, and it does not discriminate by age — children grind as readily as adults, though in adults stress is often a factor. Seven ways stress can affect your mouth covers the wider picture.

Preventing the grinding itself is very difficult. Where most damage happens at night, a grinding guard worn to bed protects the teeth. See night time tooth grinding and clenching, what is bruxism and how is it managed? and how can a night guard be used to treat TMD?. The clinical page is TMD and teeth grinding.

A sports mouthguard is a different appliance and does not do this job. It is made to absorb impact during sport, not to manage grinding, and the two are not interchangeable in either direction — what kind of mouth guard should I use? is about that sports version, and getting a new mouthguard — a trip to the chemist or the dentist? weighs a chemist boil-and-bite sports guard against one made to fit by a dentist.

In severe cases patients crack teeth, fracture existing restorations, and wear down opposing surfaces — which becomes expensive. Why does a cracked tooth hurt so much?, how will my cracked tooth be treated? and chipped and cracked teeth cover what happens next, and the price guide what it costs. It is worth trying to identify and address the underlying tension.

4. Smoking

Smoking does not directly cause decay. It affects the oral environment by introducing toxins, impairing the mouth’s ability to fight infection, and increasing the risk of oral cancer. The soft tissues bear the brunt. See oral cancer: how your dentist can help with early detection, oral cancer: signs, risk factors and how your dentist can help and what are the causes, symptoms and treatment of mouth cancer?.

Smokers should expect high rates of very severe gum disease, which over time causes tooth loss — what is gum disease? and periodontal (gum) disease. The substitutes are not neutral either: are e-cigarettes bad for my teeth? and the effects of vaping on your oral health.

5. Dry mouth

Serious for some people, because it increases the risk of both decay and gum disease, and is uncomfortable.

Causes include anatomical issues — blocked nasal passages forcing mouth breathing, or “incompetent lip seals” where the lips do not close at rest — as well as hydration levels and medication side effects. Mouth breathing: the silent habit that’s changing your face and your health covers the first; my mouth is always dry — why is this and does it affect my teeth?, my mouth always feels dry! What can I do? and what causes dry mouth during running? the rest.

Dry mouth makes oral bacteria more virulent and saliva more acidic. It is also one of the more common causes of persistent bad breath.

6. Poor oral hygiene

Worth stating bluntly: your perception of “good oral hygiene” may not match your hygienist’s. A hygienist raises technique only when they think there is a real improvement available to you. See what does a dental hygienist do?, your Smile Solutions dental hygienist visit: what to expect and dental cleans and hygienists.

The routine itself: what is the ideal daily routine for oral hygiene?, is flossing really that important?, how often should I brush my teeth? and three oral hygiene tips you need to know.

7. Neglecting the gums

Some patients are at very low risk of decay and very high risk of gum disease. Susceptibility has much to do with inflammatory response and immune system — and with diabetes, which works in both directions: diabetes and dental health: the two-way street that most people don’t know about.

There is no point having healthy teeth if they are wobbling in the bone because the supporting structures are diseased. Gum health should be checked at every check-up. Bleeding gums is the sign people most often dismiss, and when do you need deeper cleaning? explains the threshold at which a routine clean is no longer enough. Health problems linked to poor oral hygiene covers what else rides on it.

8. Heavy brushing — irreversible

The only bristle strength you should buy is soft, or extra soft. Medium and hard brushes exist because people buy them, not because they are better. Which toothbrushes do dentists recommend? and how much pressure should I apply when brushing my teeth? go further.

Heavy brushing over years — particularly with a medium or hard brush — causes considerable gum recession and wears the root surfaces. This damage cannot be reversed: over brushing: what can it do to my teeth?. Exposed root surface is also the most common source of sensitivity, and it decays far more readily than enamel, which is why fluoride and the right toothpaste matter more once it has happened.

If teeth do not feel clean after using a soft brush, the problem is usually technique or duration, not the brush. Consider an electric toothbrush, and ask your hygienist how to use it. How to care for your toothbrush covers the rest.

9. Waiting for pain

Tooth pain usually means the tooth is already severely affected. By the time you feel it, decay or infection is deep, treatment must be more invasive, and the prognosis is worse. What are the causes of toothache and what are their symptoms? and common signs and symptoms of a toothache describe what the different pains mean.

There is a second effect: patients who attend only in pain associate dentistry with suffering. Regular attenders, who often need no treatment at all, associate it with a good experience. How often should I go to the dentist?, start the New Year with a dentist check up and understanding your treatment cover the routine visit. If it is the fear rather than the schedule that gets in the way, see dental anxiety and how can I ease my anxiety about visiting the dentist?.

10. Ignoring pain

If a tooth is uncomfortable and that is not normal for you, get an opinion — even if no cause is found, it is better to be certain. I have a toothache — what could be the cause?, how can I relieve a toothache? and tooth pain and toothaches are the places to start. A GP is not the right first stop for a dental infection: I have a toothache — should I see my GP for antibiotics?.

Patients do present with a raging abscess at what was meant to be a routine six-monthly hygiene appointment, having noticed the tooth was sore for some time without knowing why. See what is a tooth abscess?, why are dental abscesses so painful? and can a dental abscess affect your general health?.

The longer pain is left, the poorer the prognosis. Know how your mouth feels when healthy, so you can tell when something is not right. What is considered a dental emergency?, what should I do in a dental emergency? and emergency dentistry cover the cases that should not wait until Monday.

Common questions

How much sugar is actually too much?

There is a number, and it is lower than most people expect. The World Health Organization recommends limiting free sugars to less than 10% of total energy intake — and ideally to less than 5%, on the basis that this “minimizes the risk of dental caries throughout the life course”.

The definition matters more than the percentage. WHO counts as free sugars “all monosaccharides and disaccharides added to foods and beverages by the manufacturer, cook or consumer, as well as sugars naturally present in honey, syrups, fruit juices”. That is the source for the point made at the top of this page: honey and fruit juice are counted, not exempted. Whole fruit is not in that definition.

And the frequency point has a mechanism behind it. WHO describes decay as the result of plaque converting free sugars into acids that destroy the tooth over time, and names three things that combine to cause it: “a continued high intake of free sugars, inadequate exposure to fluoride and a lack of removal of plaque by toothbrushing”. Each exposure restarts the acid attack, which is why ten small ones beat one large one for damage.

Is tap water enough fluoride, or do I need something extra?

They do different jobs and you generally want both.

Water fluoridation is a population measure at a low concentration: the NHMRC supports fluoridating drinking water “within the range of 0.6 to 1.1 milligrams of fluoride per litre”. Toothpaste works topically at roughly a thousand times that concentration — WHO describes the protective daily measure as “toothbrushing with fluoride toothpaste containing 1000–1500 ppm”.

On the safety question people usually mean when they ask this: NHMRC states that dental fluorosis “is caused by a high intake of fluoride from multiple sources during the time when teeth are developing inside the jawbone, usually from birth to six or eight years of age”, that in Australia it is “in most cases… classified as very mild or mild”, and that “moderate dental fluorosis is very uncommon and severe dental fluorosis is rare in Australia”. That risk window closes in childhood; it is not an argument for an adult to avoid fluoride toothpaste.

If you have exposed root surfaces from recession or heavy brushing, raise it specifically — root surface decays more readily than enamel, and that is a reason to discuss what you use, not to assume the tap has it covered.

I brush twice a day and still get problems. What am I missing?

Usually one of the other three things on the professional list. The Australian Dental Association sets out four “main oral hygiene strategies”: brushing for two minutes twice a day; using an age-appropriate fluoride toothpaste; cleaning between the teeth once a day with floss or interdental brushes; and visiting a dental professional for regular check-ups and professional cleaning.

Brushing is one of four. Cleaning between the teeth is the one most often skipped, and it covers the surfaces where decay most often starts and where gum inflammation usually begins.

Note also what the ADA puts in a separate list, headed “proven aids to oral hygiene” — toothbrush, fluoride toothpaste, interdental aids, sugar-free chewing gum and mouthrinse. Mouthwash is an aid on that list, not one of the four strategies. Using it instead of cleaning between your teeth is a swap the ADA does not make.

Does a night guard stop the grinding, or just absorb it?

Mostly the second, and it is worth being clear about that before you pay for one.

A guard is a physical barrier: it takes the wear that would otherwise land on enamel and restorations. healthdirect Australia describes the treatment the same way — a mouthguard or splint “to help protect your teeth” — and lists relaxation techniques and counselling alongside it, because the guard does not address the cause.

Where the evidence is genuinely weak is pain. The 2024 Cochrane review of occlusal interventions found that a splint “may reduce pain in muscles when chewing compared to receiving no treatment, but the results are very uncertain”, and “little or no evidence” of other benefits. So: reasonable as protection for teeth that are visibly wearing or cracking; not something to expect a guaranteed improvement in jaw pain from.

One correction to the note above about children. healthdirect's position is that “young children sometimes grind their teeth but usually grow out of it”. Grinding in a child is worth mentioning at a check-up so the wear can be recorded; it is not usually a reason for an appliance.

Of the ten, which should I deal with first?

If you want a priority order rather than a list, use two principles.

First, the irreversible ones outrank the rest. Acid wear and recession from heavy brushing do not get better; every month of the habit adds permanently to the total. Decay and gum inflammation caught early can be arrested or treated. So a hard-bristled brush and a daily soft-drink or sparkling-water habit are the two cheapest things on this page to change, and two of the most expensive to leave.

Second, weight by what the evidence says drives disease. WHO calls the consumption of free sugars “the most common risk factor for dental caries”. If you are choosing one thing, that is the one with the broadest evidence behind it.

Everything else on the list is real, but those are the levers with the best return.

What is the cost of leaving this, compared with dealing with it?

The honest answer is that prevention is priced per visit and repair is priced per tooth, and the gap widens the longer you wait. The cost drivers to be aware of: how much tooth is left (a filling, a crown and a root canal are three different scales of work), how many teeth are involved, whether the gums need staged treatment over several appointments rather than a single clean, and whether anything has to be replaced rather than repaired.

Ask for a written treatment plan with itemised costs before you agree, ask what your health fund pays on each item, and ask what the total will be by the end rather than the cost of the first visit. Our fees and understanding your treatment show how that is set out here.

For the scale of what “leaving it” costs nationally: the Australian Institute of Health and Welfare counted 88,600 potentially preventable hospital admissions for dental conditions in Australia in 2023–24, a rate of about 3 per 1,000 people, up from a low of 2.6 per 1,000 in 2019–20. A hospital admission is the most expensive possible endpoint for problems that mostly began as one of the ten items above.

Related reading

Practical details

Smile Solutions, Level 1, 220 Collins Street, Manchester Unity Building, Melbourne VIC 3000 — getting here. Phone 13 13 96, contact us, or theteam@smilesolutions.com.au. Monday–Friday 8.00am–6.00pm, Saturday 8.30am–1.30pm, Sunday by appointment.

Specialist registration can be verified on the AHPRA register, or by calling 1300 419 495. The practice’s registered specialists are identified as such within the full team.

Published 23 May 2016. General information only; it does not replace advice from your treating practitioner.

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