What is tooth decay and what causes it?

Tooth decay (caries) is the destruction of your tooth enamel, the hard, outer layer of your teeth. Plaque, a sticky film of bacteria, constantly forms on your teeth. The bacteria sticking to your teeth in plaque break down sugars and other carbohydrates that we eat, and produce acids. These acids dissolve the enamel and dentine that make up the tooth structure, and create a hole in the tooth. This process is called dental caries or tooth decay.


Once a hole has developed in the tooth surface you will need to have the decay removed from the tooth and a filling placed to seal the surface and build up the shape of the tooth again. Tooth decay may occur in the enamel, around and under fillings and in the softer root dentine exposed as gums recede. Decay around the edges, or a margin, of fillings is also common for older adults. Because many older adults lacked benefits of fluoride and modern preventive dental care when they were growing up, they often have a number of dental fillings. Over the years, these fillings may weaken and tend to fracture and leak around the edges. Bacteria accumulate in these tiny crevices causing acid to build up which leads to decay.


Common causes

  • Frequent intake of sugary drinks, including fruit juices and fizzy drinks
  • Snacking on foods high in sugar
  • Poor or lack of tooth brushing with fluoride toothpaste
  • Lack of cleaning between teeth
  • Dry mouth


Warning sings

  • Tooth covered in food and debris
  • Holes in teeth
  • Broken teeth
  • Brown or discoloured teeth
  • Tooth sensitivity to hot or cold foods
  • Difficulty eating or chewing
  • Toothache
  • Bad breath
  • Swelling in the face and jaw area

You can help prevent tooth decay by following these tips:

  • Brushing twice daily with fluoride toothpaste
  • Once daily, clean between your teeth daily with floss or interdental cleaner.
  • Reduce the frequency of sugary foods and drinks, especially in between meals – and replacing them with healthy alternatives such as water than a fizzy drink
  • Regular professional check-ups to spot and treat tooth decay, to stop further damage to your teeth