Structure of teeth
The structure of teeth of an animal correlates to its diet. Humans are called omnivores because they eat both animal and plant material. Humans have incisors, canines, premolars and molars, each type of teeth determined in size and shape by its function:
- The incisors cut pieces off the food, such as when biting into an apple.
- The canines have a more pointed shape than the incisors but a bit smaller. They are use in tearing of pieces of food such as meat.
- The premolars and molars are similar in shape and function. They are used to crush and grind the food into small pieces easier to digest.
The part of a tooth visible above the gum is called the crown and the rest, embedded in the jaw bone, is called the root. On the surface, the crown is covered by a very hard enamel layer. Below it is a softer layer called dentine. Then there is pulp cavity inside the dentine. The pulp cavity is the one that contains nerves and blood vessels which entre the tooth through a small hole at the base of the root.
Tooth decay starts when small holes (known as cavities) appear
in the enamel. These cavities are usually caused by acids which are a result of the bacteria on the tooth’s surface feeding on the sugars deposited on the teeth producing acid. The acid dissolves the calcium salts in the tooth enamel. The enamel dissolves and exposes the dentine to the acids.
Since the dentine is much softer than enamel and it dissolves more quickly forming cavities. The cavities eventually expose the nerve
endings in the tooth.
The irritation of the acids on the nerve endings then causes toothache. Cavities should be cleaned and filled by a dentist, otherwise the bacteria will enter the pulp cavity and cause a painful abscess at the root of the tooth. When this happens, the only way left to treat this condition is will be to pull out the tooth.
The biggest cause of tooth decay is the presence of refined sugar (sucrose). This therefore means that the best way to prevent tooth decay is to avoid taking in sugar frequently, either as sweets or sweet drinks or any other sweet snacks.
It is wise to visit a dentist at least once every 6 months or so, so that any caries or gum disease can be detected and treated at an early stage.
Gum disease (periodontal disease)
Teeth are covered by a layer of mucus and saliva that contains many bacteria. This bacteria live on the food residues in the mouth, building up plaque on the teeth. If not removed, the plaque forms a hard layer of "tartar" or calculus which spreads down the tooth into the narrow gap between the gum and enamel. This causes an inflammation called gingivitis, which results in redness and bleeding of the gums and to bad breath.
If not treated, gingivitis progresses to periodontitis in which the fibres holding the tooth are destroyed. The tooth becomes loose and fall out or has to be removed.
There are many ways of preventing dental or gum disease:
- regularly cleaning the teeth with a toothbrush and toothpaste to remove plaque.
- rinsing the mouth regularly with mouthwashes to reduce the number of bacteria in the mouth.
- flossing the teeth with a waxed thread.