The surfaces of all your teeth are always covered with a thin, sticky layer of bacteria. This layer of bacteria is called plaque.
When you eat anything sugary, the bacteria on your teeth turn the sugar into energy and acid. This acid softens and dissolves the hard enamel surface of your teeth in a process called demineralisation. Over time, demineralisation can cause cavities to form in your teeth. This is known as tooth decay or dental caries.
The enamel surface of your teeth doesn't contain any nerves, so you won't feel any pain when you first start to get a cavity. Eventually, however, a cavity may reach the dentine – the substance underneath the enamel that forms the bulk of your tooth and covers the blood vessels and nerves. Dentine is sensitive to pain, so more advanced cavities may cause pain, especially when you eat or drink anything hot, sugary or acidic.
Saliva helps to wash away and neutralise the acid on your teeth. It contains minerals that replace those that are lost from the enamel during demineralisation. This replacement process is called remineralisation.
Demineralisation and remineralisation happen every time you eat or drink something sugary. If you consume sugary food or drinks too often, the saliva doesn't get long enough to fully remineralise your teeth. This will increase your risk of getting tooth decay.
Gum disease is inflammation of your gums and may also involve damage to the bone that anchors your teeth into your jaw. Gum disease is very common and affects more than half of adults who have their own (natural) teeth.
If you don't clean plaque off your teeth regularly, your gums will become red, swollen and shiny and they may bleed. This is the early stage of gum disease called gingivitis. You can easily treat gingivitis by removing the plaque through thorough brushing and flossing, and your gums will get better.
It’s important to treat gingivitis because otherwise your gums may begin to pull away from your teeth, leaving a little pocket around each tooth. This is known as periodontitis. If you develop this, plaque that you can't reach with a toothbrush can become trapped in the pockets around your teeth. Over time the plaque will harden to become tartar (calculus), which you can’t remove by brushing. Plaque and tartar can build up and cause further irritation.
As time goes by the pockets can get deeper and more difficult to clean, so they are more likely to become infected. The plaque attacks your gums and can start to attack the bone that holds them in place, making them wobbly and sensitive. If left untreated over a number of years, your teeth may become very loose and need to be taken out by a dentist.
You can prevent gum disease by controlling the amount of plaque and tartar that build up on your teeth. Regular visits to your dentist and hygienist, brushing and flossing your teeth properly and stopping smoking will help.
Dental erosion is the loss of enamel and dentine caused by acid attacking the surfaces of your teeth. However, unlike with tooth decay, the acids don’t come from plaque bacteria. They usually come from acidic drinks such as fruit juices, fizzy drinks and squashes – this includes the 'diet' varieties. Certain foods, for example crisps or vinegary sauces such as ketchup, can also cause dental erosion. Dental erosion is common and often affects children.
You can help to prevent dental erosion by limiting the number of acidic drinks you consume. If you have a young child, try to give him or her only water or milk to drink. If your child does have an acidic drink, make sure he or she has it at meal times and drinks it out of a cup or uses a straw – this reduces how much of the drink comes into contact with the teeth. Don’t give your child acidic drinks in a feeding bottle.
Stomach acid in vomit can also cause dental erosion. If you have a health condition that causes you to be sick frequently (for example bulimia nervosa or digestive problems), you may risk damaging your teeth.
You can’t reverse the damage done by dental erosion. It can cause your teeth to become sensitive if the dentine becomes exposed. If this happens, your teeth may look yellow (because dentine is this colour) and you’re more likely to get tooth decay.
Good oral hygiene is very important to help prevent tooth decay and gum disease. It involves cleaning your teeth at least twice a day with fluoride toothpaste, visiting the dentist and hygienist regularly and limiting the amount of sugar in your diet.
Brush your teeth
Brushing your teeth regularly is very important for removing plaque. To get the most benefit from brushing your teeth:
- use a toothbrush with a small head and synthetic bristles
- use fluoride toothpaste to protect against decay
- start at one side of your mouth and move round to the other side, brushing all the tooth surfaces thoroughly
- pay particular attention to your gumline, angling the bristles into the area where your gums meet your teeth
- brush at least twice a day for about two to three minutes
- replace your toothbrush at least every three months or sooner if the bristles are worn down
You may prefer to use an electric toothbrush. There is some evidence that certain types of electric toothbrush are more efficient at removing plaque than brushing by hand. However, the thoroughness of your cleaning is much more important than what type of brush you use.
Clean between your teeth
Dental floss or interdental brushes can help to remove plaque and small bits of food from between your teeth and under your gumline – these are areas that a toothbrush can't reach. It's important to use the correct technique, so ask for advice from your dentist or hygienist.
However, even thorough brushing and flossing may not remove all plaque. This is because most people have irregularities in their teeth where plaque can build up and harden into tartar. This can only be removed by a dentist or hygienist using special tools in a process called scaling.
Fluoride mouthwashes can help to prevent tooth decay. Some antiseptic mouthwashes reduce plaque bacteria on your teeth and help to prevent gum disease. If you use mouthwash to freshen your breath, talk to your dentist for advice as bad breath may be a sign of poor oral hygiene (see our frequently asked questions for more information). Always choose an alcohol-free mouthwash, read the information on the box or bottle and if you have any questions, ask your dentist or hygienist for advice.
Chewing sugar-free gum after a meal stimulates the production of saliva, which helps to neutralise plaque acid. Some chewing gums contain a sugar-free sweetener called xylitol, which may help to reduce tooth decay. However, more research is needed to understand how this might work. It’s important to remember that chewing gum isn’t a substitute for brushing and flossing.
Control sugar in your diet
Eating sugary foods and drinks encourages tooth decay. However, it's how often you eat these sugars, rather than the amount, that is important. Try not to eat or drink them between meals to give your teeth a chance to be remineralised by saliva. Limiting sugar between meal times is particularly important for children. It's also good for your general health to reduce your sugar intake.
Alcohol and tobacco
Smoking can stain your teeth and increase your risk of gum disease and tooth loss. Certain alcoholic drinks and the sugary mixers used with them often contain lots of sugar and so increase the risk of tooth decay.
Dentists and hygienists can help you to keep your teeth healthy.
At check-ups your dentist will try to find any problems early and give you advice and treatment. He or she can advise you on how often you should have a check-up. For adults, this can vary from every three months to every two years if you have very good dental health and hygiene.
Children and adults who are at high risk of developing dental problems may need to see a dentist more often. You may be at high risk if you smoke, have a diet that is high in sugar or have had lots of dental treatment in the past.
What can I do about bad breath?
If you have bad breath (halitosis), it's important that you see your dentist so that he or she can identify the cause. It’s important that you brush your teeth and gums regularly to remove any food and plaque that can cause bad breath.
A range of things can cause bad breath. It's important to go to your dentist who will be able to find out what is causing it. Bad breath may be caused by a build-up of bacteria and food around your teeth and gums because of poor dental hygiene. There are a number of other causes of bad breath including gum disease, smoking and eating strong-smelling foods. Certain medicines and medical problems such as dry mouth, diabetes and infections can also cause bad breath.
Things that you can do that may help include:
- brushing your teeth and gums thoroughly at least twice a day for a minimum of two minutes, and following the advice of your dentist or hygienist carefully
- using dental floss or interdental brushes to remove plaque and food from between your teeth
- stopping smoking
- not eating strong-smelling foods (such as onions, coffee and garlic)
If your bad breath doesn’t improve, see your dentist. He or she may recommend some or all of the following.
- Treatment for any decayed teeth or gum disease.
- Improving your oral hygiene, including brushing and flossing your teeth properly and using mouthwash or a tongue scraper.
- Antibiotics if a throat, mouth or chest infection is causing your bad breath.
If your dentist can't find out what is causing your bad breath, or suspects that your bad breath is caused by a medical condition, he or she may advise you to see your GP.
Should I brush my teeth immediately after I have eaten?
No, wait at least 20 minutes after eating before you brush your teeth.
When you eat and drink, the enamel on your teeth becomes softer because of the acids being released. If you brush straight after eating, over many years it can cause the enamel to wear away and expose the dentine underneath. This can cause pain and sensitivity and may lead to tooth decay or erosion.
Wait between 20 minutes and an hour after eating before you brush your teeth. This will give your saliva enough time to neutralise the acid caused by eating and drinking.
The best time to brush your teeth is before breakfast and last thing in the evening before you go to sleep. It's particularly important to clean your teeth at night because when you're asleep the flow of saliva slows down, leaving your teeth more at risk from decay.
How often should I clean my dentures?
Clean your dentures twice a day, just as you would your own (natural) teeth.
It's important that you spend time cleaning your dentures to remove small bits of food and to prevent stains and a build-up of plaque and tartar. It isn't sufficient to only soak them in a denture-cleaning product.
Follow the tips listed here to make sure you clean your dentures correctly.
- Use a soft toothbrush, toothpaste and soap and water.
- Clean all the surfaces of your dentures.
- Don't brush too hard as this can damage the dentures.
- Rinse your dentures thoroughly with water after cleaning.
- Always clean your dentures over a bowl of water or a soft surface in case you drop them.
Over time you may notice a build-up of plaque and tartar on your dentures. If this happens, see your dentist or hygienist and he or she can remove it using a special cleaning machine.
If you’re considering using a denture-cleaning solution, powder or tablet, speak to your dentist first. Some products can permanently damage certain types of denture.
Don't soak your dentures in hot water or products that contain bleach as these may weaken them. If your denture has metal parts, you must be particularly careful about your choice of cleaning fluid.
Why have my teeth and tongue suddenly turned black after treatment for a gum infection?
If you’re prescribed a mouthwash or oral spray that contains a chemical called chlorhexidine gluconate, it may stain your teeth and tongue.
Chlorhexidine mouthwash is a very commonly used and effective antiseptic treatment, but it can cause brown, greenish or even black staining of your teeth and tongue. It can also stain fabric.
Make an appointment with your dentist if you notice staining on your teeth after using chlorhexidine mouthwash. He or she will be able to confirm whether the staining is caused by your mouthwash or something else. If it's chlorhexidine staining, your dentist or hygienist can remove it using a special electric toothbrush and gritty toothpaste. Your tongue should go back to its usual colour once you stop using the mouthwash.
To prevent further staining when you use chlorhexidine mouthwash follow the instructions on the bottle carefully. There will be less staining if your teeth are clean before you use the mouthwash. Brush your teeth at least half an hour before using the mouthwash. Alternatively brush your teeth, rinse your mouth with water, wait five minutes and then use the mouthwash (this is necessary because some ingredients in toothpaste stop chlorhexidine mouthwash from working).
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- Guideline on xylitol use in caries prevention. American Academy of Pediatric Dentistry. www.aapd.org, published 2011
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- Joint Formulary Committee. British National Formulary (online). London: BMJ Group and Pharmaceutical Press. www.medicinescomplete.com, accessed 20 June 2013
- SPC. Chlorhexidine gluconate antiseptic mouthwash peppermint flavour 0.2% W/V oromucosal solution. electronic Medicines Compendium. www.medicines.org.uk, published November 2011
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