We all know that our teeth are covered by a hard substance called tooth enamel, but what exactly is tooth enamel, how is it formed and how does it get damaged? These are three critical questions when it comes to the importance to our general wellbeing of tooth enamel.
What Exactly is Tooth Enamel?
Tooth enamel is the hardest substance found in the human body. Its primary function is to protect the underlying layers in the human tooth, and particularly the extremely sensitive pulp (which is found in the centre of the tooth), from attack by bacteria.
Enamel is the most mineralised tissue in the human body, which accounts for its hardness. This hardness is an advantage on the one hand, as it prevents bacteria from attacking the underlying dentin and pulp, but unfortunately, a disadvantage on the other hand, because the very hardness has a corresponding brittleness. This brittleness makes the enamel susceptible to cracking or chipping.
How is Enamel Formed?
The formation of enamel normally starts in the fourth month of pregnancy. The teeth of the baby are below the gum line, and will only erupt after the mineralisation of the enamel is complete. The formation of teeth goes through 4 phases. It is only in the last, or crown phase, that the formation of enamel occurs. The formation of enamel is a complex process, but basically goes through 2 distinct phases, the secretory stage and the maturation stage.
Enamel formation is accomplished by cells known as ameloblasts. In the secretory stage, the ameloblasts cause the formation of the enamel matrix which, during the maturation phase, is fully mineralised and hardened to create enamel. In the maturation phase the ameloblasts change their function from a secretory role to a transportation role. Proteins used in the mineralisation of enamel are principally ameloblastins, enamelins and tuftelins. These proteins are transported to the site of the enamel matrix. Once the mineralisation is complete the ameloblastins are destroyed and only the enamelins and tuftelins remain.
There is therefore very little organic material left in tooth enamel, which means that once damaged enamel cannot be repaired, as in bone tissue.
How is Tooth Enamel Damaged?
Sugary foods and acidic fruits and soft drinks are the principal causes of tooth decay. The bacteria, found in everybody’s mouth, interact with the sugars and acids in the food to form lactic acid, which attacks and eats into the enamel in a process called de-mineralisation. Once the lactic acid eats through the enamel, it encounters the dentin, which is a much softer substance. Once through the dentin, the bacteria and lactic acid have arrived at the pulp in the centre of the tooth. Infection of the pulp causes the toothache.
Funnily enough, it is the frequency of the sugar intake not the amount that causes the most damage. The bacteria have an active window of approximately 30 minutes in which to do their damage, before the natural defences of the body kick in and neutralise the acid. So having a cup of sugar is as bad as having a teaspoon of sugar. It’s not the amount of sugar that is critical, but the frequency of sugar intake that matters. Confining your sugar intake to one dessert at the end of the evening meal is far less damaging than frequent sweets and soft drinks throughout the day.
Do you have any questions about your teeth that this article doesn’t answer? Talk to our dentist at Ironwood Dental. He or she will have the answers you’re looking for!