Human Digestion System Essay
There are 4 types of teeth: incisors, canines, premolars and molars. There are 4 incisors, 2 canines, 4 premolars and 4 molars on both the upper and lower jaw. The arrangement of each type of tooth is shown on Fig.1 (in-text citation). Each types of tooth also have different shapes and functions. Incisors are chisel shaped. It is used for biting off pieces of food. Canines have one pointed cusp; it is used for grasping, holding, tearing food (in-text citation). Premolars …show more content…
However, if they don’t, many different dental diseases may occur.
There are many types of dental diseases, but the most common ones are gum diseases and tooth decay. The cause for these two diseases is plaque. Plaque is a sticky film consisting of bacteria and saliva formed over the teeth. At first it is very soft, and easy to remove, but it slowly hardens to tartar and later on, it cannot be removed by brushing.
Gum disease is occurred when the plaque is not removed properly, and the bacteria infected the gums. The infected gum will swell, become inflamed, and it may bleed when brushing teeth. If not treated properly and the bacteria is allowed to work down towards the roots, the tooth will me loosened and will need removing. Another type of disease is tooth decay. When sugar is left on the teeth, bacteria will feed on the sugar, and use it for respiration and change it to acid. The acid will slowly dissolve the enamel, and if it is not treated in time, the acid will dissolve the dentine and the pulp cavity. As the acid starts dissolving the pulp cavity, the nerve cells will be damaged, and the person will start feeling the