How to prevent tooth decay

Tooth decay is an infectious disease produced by bacteria. Some people are lucky and don’t catch it, but most people do catch it early in life and then are predisposed to developing tooth decay. We do not yet know exactly how this disease is transmitted, but if you are an adult and you have a history of tooth decay (as most people do), try not to share spoons, glasses, bottles (or saliva when kissing) with small children, and do not put their pacifier into your mouth – just to be on the safe side.

Genetics may also predispose you to developing decay.

But neither of these are factors which we can influence.

One thing we can influence is frequency of sugar intake. This is by far the most important reason for tooth decay. Fluoride is another factor. Dry mouth is another, less common reason. On this page, you can read about:

What is tooth decay?

Tooth decay is a process which softens and destroys the hard tissues of the tooth. These tissues are called enamel and dentine. Bacteria, feeding on sugar, produce the acid that fuels this process.

It is treated by removing the parts of the tooth that have gone bad, and replacing the missing parts with a ‘filling‘.

There can be a direct relationship between stress and tooth decay. Stress (feeling upset) can lead to an increased desire to “sweeten” our lives and ourselves. This results in a greater frequency of sugar in the diet. The increased frequency of sugar in the diet leads to tooth decay.

It is true that there are many other factors in tooth decay, but this is the major factor and one over which we have direct control.

What action can we take?

The good news is that you do not need to give up anything!!

The problem is frequency or the number of times per day that sweet things are placed in the mouth. So we deal with the frequency.

The simple secret is to make a decision to leave 3.5 to 4 hours between sweet consumptions. Immediately the frequency is reduced to 4-5 maximum per day. It also means that the teeth have this time (4 hours) to recover from the effects of acid produced by sugars.

The teeth are then fully recovered before the next acid attack.

Fair Play to You and Your Teeth

This is how I advise my patients. I like to keep it simple and easily understandable. We call this method “Fair Play To You And Your Teeth” because you get what you want and your teeth get what they want! It is fair and even-handed.

Have what you want! — 3.5 – 4 hour break — Have what you want!


If you feel that you must eat something in the Recovery Time ensure that it is sugar-free.

Dental Fear Central would like to thank Philip Christie (M.Dent.Sc.) for allowing us to reproduce this section on how to prevent tooth decay from his book “Something to Chew On”.

Most foods do contain sugars (like sucrose, glucose, or fructose), so the best thing to do is to eat sweets at mealtimes, as a dessert.

Some additional tips:
  • Use a full-strength fluoride toothpaste (1350-1500ppm fluoride), and/or a fluoride mouthwash (especially if you don’t like to use toothpaste because you don’t like the taste). Fluoride appears to counteract the effects of sugars in the diet. Anecdotal evidence suggests that switching to a non-fluoride toothpaste can result in more cavities.
  • Avoid boiled sweets, which stay in contact with the teeth for a long time. There are many sugar-free alternatives – sweets that have been sweetened with Xylitol can even help prevent tooth decay! Xylitol sweets and gum inhibit the growth of streptococcus mutans, one of the main bacteria involved in tooth decay.
  • Be aware of hidden sugars, especially in soft drinks and fruit juices. Remember that “no added sugar” doesn’t mean that a product is sugar-free – they may contain sugars, or the sugars may be listed as ‘carbohydrates’.
  • Soft drinks can be particularly bad for teeth because we tend to drink them over longer periods of time, throughout the day. Choose diet versions instead if you want to avoid tooth decay but can’t cut down on soft drinks.
  • While diet soft drinks can’t cause tooth decay, they can cause acid erosion, so you should try and limit the amount of time they’re in contact with the teeth. This is especially important for children (also, articifical sweeteners are not suitable for young children – ask your dentist if you’re not sure).
  • Similarly, if you like sweet tea or coffee and drink it throughout the day, switch to sweeteners instead of sugar. Some teas have been shown to actually protect your teeth from decay. Tea and coffee themselves do not contain sugar.
  • Water and milk are good choices, and also diluted sugar-free squashes (1 part cordial to 10 parts water).
  • Fruits are very healthy, but they are also acidic and contain sugars. Although they’re not as sticky as some other sweet things, you shouldn’t eat them as a snack during the Recovery Time. If you do eat them as a snack, try to eat something alkaline (non-acidic) afterwards such as cheese.
  • Savoury snacks are better, such as nuts, raw vegetables, or cheese.
  • Using sugar-free chewing gum after meals can help prevent tooth decay, because it makes your mouth produce more saliva. The extra saliva helps to cancel out the acid in your mouth after eating or drinking.

Dry Mouth

A severely dry mouth is much less common than frequent sugar intake, but it also increases the risk of tooth decay. Saliva is very important in the fight against tooth decay. It contains a number of ingredients which help to fight the bacteria that form dental plaque and cause decay and gum problems.

There are certain medical conditions (especially Sjogren’s Syndrome) which can cause very dry mouth. Radiation treatment and damage to the salivary glands are other causes. Also, certain drugs including tricyclic antidepressants, antispasmodics, some anti-psychotic drugs and HAART for people living with HIV can all cause dry mouth. Some women also experience dry mouth as they are going through the menopause or taking Hormone Replacement Therapy.

Ask your doctor if you are taking medication and it’s causing you dry mouth, to see whether the medication can be changed.

There are many products which can help with dry mouth. The main manufacturer (in the U.K. at least) is Biotene, but there are many artificial saliva products, lozenges , gels and sprays which may help. Ask your dentist or pharmacist for advice and recommendations. Make sure that any lozenges or boiled sweets you use to alleviate dry mouth are sugar-free.

It is important to keep sugary foods and drinks to mealtimes only. Your dentist may also want to prescribe a toothpaste with high fluoride content.

Avoid mouthwashes which contain alcohol, as these can dry out your mouth!

How to slow down or stop existing decay from getting worse

You may wonder if it is possible to stop an existing cavity from getting worse – for example because you cannot see a dentist yet due to fear or finances. The following answer from our forum provides some tips:

“Decay is a dynamic process, so far as we’re aware, the surface of teeth is constantly in a state of demineralising/remineralising. Decay happens when something tips the natural balance too far in the demineralising direction.

Since you need bacteria/fermentable carbohydrate/susceptible teeth all to be present for decay to progress, then changing the balance of one of the three will change the decay progression.

It’s not likely that you can alter the bacteria much, although obviously making sure that you’re cleaning the area thoroughly 3 times a day will help. Cut down the carbohydrates in your diet by restricting them to meal times and make the enamel less vulnerable to attack by getting lots of fluoride into it are the best way to deal with decay. The easiest way to do that is to get some fluoride toothpaste and when you’re finished brushing your teeth with it, rub it vigorously into the affected areas and DON’T rinse out afterwards. You can slosh about loads of fluoride mouthwash as well, but getting the paste in there is best.” (Gordon Laurie, BDS)

Further Reading

Some of the information on this page was taken from the excellent Dental Health Foundation’s Tell me about… pages. You can read more here:

Tell me about… Diet
Tell me about… Dry Mouth