Every time you eat food containing any sugar your teeth will decay for 45 minutes. Brushing Your Teeth Immediately After - won't help much. It takes 6-8 hours for the damage done in this 45 minutes to be naturally repaired by your saliva.
Tooth decay (caries) is a common problem affecting teeth in people of all ages. There are bacteria which live in plaque. These bacteria feed on sugars in our food and drink (such as sucrose, glucose and fructose), and produce acids.
These acids damage the tooth's surface by softening it by dissolving away the minerals in the tooth's outer surface (enamel). Once all the sugar has been used up, the acid gradually disappears and the tooth's surface starts to repair itself. Each time something sweet is eaten or drunk, plaque bacteria produce more acids, which attack the tooth's enamel again.
In time, this causes the formation of holes or cavities which require fillings or crowns. You may find they can cause you toothache of varying degrees of severity. If this decay is left it may lead to the death of your tooths nerve or even on to an abscess. If this happens you may need a root filling or even an extraction.
The best way to prevent decay is to brush well and regularly with fluoride toothpaste, floss and limit sugary foods. If you have any sugary food make sure it is eaten together with normal meals and not eaten as regular snacks.