What Causes Tooth Decay

When your teeth have suffered permanent damage to the hard enamel, you tooth has a cavity.  Now that the dentist has diagnosed why your tooth is sensitive to heat and cold, the dentist can treat your tooth decay.  But you want to know what caused the problem and how to prevent it going forward.


Most often there are a number of causes of tooth decay or dental caries, not just one reason and it is a process that happens over time.

To start, plaque, or a white film, forms on your teeth after the bacteria in your mouth starts to feed on the sugars and starches from the food you eat.  If the plaque is not cleaned off the teeth, then the plaque can harden in place and form into tartar.  Tartar is more difficult than plaque to remove and it allows a place for the bacteria to hide from at home brushing.

Next, the plaque starts attacking the hard enamel of your teeth.  The bacteria uses the sugars and starches from your diet to form acid which weakens the enamel.  Once the acid starts to create a small hole in the enamel, a cavity has started to form.  After the plaque attacks the enamel, the plaque moves to the deeper layer of tissue called the dentin.  Dentin is softer than the enamel and it is directly connected to the nerve in the tooth so you may have some tooth sensitivity if your tooth decay has reached this stage.

Then the tooth decay continues to move to the next layer of tissue called the pulp.  Like dentin, pulp has nervous tissue but it also has blood vessels.  As the bacteria continues to grow and cause deterioration of your tooth’s tissues, the tissues become swollen from the irritation caused by the bacteria.  If the inner tissues of the teeth swell, then there is pressure inside the tooth causing you pain.  The bacteria can move to the root of the tooth or even the jaw bone.

Risk factors

According to the World Health Organization, almost 48% of the world’s adults have tooth decay on their permanent teeth.  While it is common, you can minimize your risk for cavities.

  • Your Diet – Foods high in acid and high in sugar help the bacteria grow in your mouth.  Also, foods and drinks that are not easily washed away by saliva like soda and dried fruit can cling to your teeth as reliable food sources for the bacteria.
  • Tooth Location – Your molars in the back of your mouth have more grooves and are not easy to reach when brushing.  The uneven surface of these teeth offer the bacteria more places to hide.
  • Poor Brushing Habits – We know that dentists recommend brushing twice a day and flossing between our twice-yearly appointments, but if you don’t brush adequately then the plaque has a chance to harden.
  • Heartburn – The stomach acid that causes you discomfort can also deteriorate your teeth over time.
  • Dry Mouth – If your mouth is not able to produce enough saliva due to certain medications or diseases, then your mouth does not have a chance to wash away plaque throughout the day.
  • Lack of Fluoride – When you get enough fluoride, your mouth is able to use it to repair damage caused by plaque and keep your teeth strong.  You can find fluoride in drinking water, salt, toothpaste and even oral rinses.

More on Tooth Decay : What is Tooth Decay?