Save that smile

So you brush your teeth after every meal, choose herbal over fizzy drinks and snack on fruit not sweets. It might sound like the ideal formula for perfect teeth but it's not. Any one of those habits could increase your risk of dental erosion or decay. Take a look at surprising things that could ruin your smile.

Eye drops

It sounds unlikely but anti-inflammatory eye drops can contribute to tooth decay. They are one of a number of medicines — including antidepressants, ibuprofen, antihistamines and blood pressure medications — that cause dry mouth. They reduce the production of saliva, which acts as a barrier and protects the teeth by neutralising acidic foods such as oranges and the acid produced by bacteria as they break down foods.

Karen Coates, dental adviser to the British Dental Health Foundation, says: "If you are having the odd painkiller here and there, you will probably be fine. But if you take a daily medication, your teeth will be more vulnerable."

Cut the risk: Lozenges, gums and gels are available over the counter for dry mouth and to encourage the production of saliva, Karen says. You could also suck sugar-free sweets for the same effect.

Healthy snacks

Even if you're snacking on healthy fruit, seeds and nuts, it's eating little and often that can do your teeth harm.

A tooth can withstand five acid attacks a day, Karen says. Saliva takes an hour to neutralise the acid created by a food or drink. So if you have a can of fizzy drink and sip it all day long, the acid in your mouth will be under constant attack.

Cut the risk: Stick to three meals a day and avoid snacking. If you must snack, eat it all at once, rather than picking at it, so that the saliva can neutralise the acid generated in the mouth. After food, rinse your mouth with water or chew sugar-free gum to encourage saliva.

Pregnancy

Many dismiss it as just an old wives' tale but motherhood really can ruin your teeth. About 50 per cent of pregnant women will develop gingivitis— inflamed gums that bleed during brushing.

Gingivitis is usually caused by food that gets trapped between the teeth and gums, producing bacteria that lead to inflammation.

The raised levels of oestrogen and progesterone circulating in a pregnant woman's body causes increased blood flow to all parts of the body, including the gums, which can become puffy and inflamed so they bleed when brushed.

Cut the risk: If you're pregnant, brush twice a day for two minutes each time, floss after meals and do not reduce your brushing just because you see blood, says Louise Childlow, of the British Dental Health Foundation.

Swimming

A study of 500 swimmers found 66 per cent of them had damaged teeth as a result of chlorine.

Chlorine affects the pH of the water and makes it acidic, so swallowing it can lead to tooth erosion, Louise says.

This can result in yellowing teeth because the acid strips the enamel and starts to reveal darker-coloured dentine underneath. It is not a common problem but may be an issue for regular swimmers who spend time in the pool each day.

Cut the risk: Try to keep your mouth closed while swimming. Don't brush your teeth straight after your dip because at this time the surface of the teeth could be softened by the acidic chlorine and could be easily brushed away.

Video games

People who play a lot of computer or video games have twice as much tooth decay as those with more athletic interests, according to a study from the University of Iowa. The researchers said that when you are absorbed in a game or TV programme, you're more likely to binge on sugary snacks and lose focus of how much you are popping into your mouth.

Cut the risk: Fill your kitchen cupboards with savoury rather than sweet snacks.

Brushing after eating sweets

If you chomp on chocolate or sweets, don't be tempted to undo the damage by brushing straight away. After eating sugary foods, your mouth becomes acidic, which softens the tooth enamel slightly. If you brush your teeth straight away, you will brush away some of the enamel, leading to tooth erosion and sensitivity.

Cut the risk: Wait at least half an hour after eating before you brush your teeth. Teeth should be cleaned twice a day — ideally before breakfast (though you can eat straight after brushing). Don't rinse your mouth after the evening clean, as the fluoride in the toothpaste will protect teeth through the night, when saliva production drops.

Diabetes

Unmanaged diabetes can lead to high levels of glucose in the fluids in the mouth, which can lead to decay. The condition can also affect the blood vessels and blood flow to the gums, which can weaken and leave them prone to infections, resulting in gum disease — and, ultimately, the loss of a tooth.

"Many people with diabetes don't realise the risks to their teeth," says Dr Keith Cohen, a dentist specialising in restorative work.

Cut the risk: Keep a close eye on your blood sugar levels.

Excessive brushing

"Some people think giving their teeth a really good scrub four times a day will keep them clean but they could be doing more harm than good because this can cause erosion," Dr Keith says.

Scrubbing back and forth wears away the tooth surface at the gum.

Cut the risk: Stick to using a soft or medium brush. Keep it at a 45-degree angle to your teeth and use a gentle, circular motion.

Herbal tea

Fruit-flavoured teas are three times more damaging than orange juice, a study at the University of Bristol Dental School found. Fruit teas are acidic and eat away at tooth enamel, with lemon and blackcurrant among the most damaging.

Cut the risk: Stick to black or green tea. Compounds in black tea attack the bacteria that form plaque and prevent the plaque from sticking to teeth, US researchers found.

Recently, a study at the University of Tohoku in Japan found that drinking one or more cups of green tea a day reduces the risk of cavities. The antioxidants, called catechins, in the tea stop bacteria in the mouth from producing acid.