Read the passage below and then answer the following questions.
When you eat or drink something, an enzyme in your saliva breaks down the food particles and sugars so they can be digested. This process turns everything you eat or drink into a type of acid. This acid then combines with the bacteria in your mouth, as well as saliva and small food particles, to form plaque. Plaque is a sticky, colorless film that coats the teeth and dissolves their protective enamel surface. If plaque is not removed, it mixes with minerals to become tartar, a harder substance. Tartar requires professional cleaning to be removed.
It is easy to brush away plaque shortly after eating. If you do not brush and floss your teeth daily, however, food particles remain in your mouth and promote bacterial growth between teeth, around the gums, and on the tongue. This results in tooth decay. Over time, tooth decay causes cavities, or holes in the teeth that occur when plaque eats into a tooth’s enamel. Cavities are also known as dental caries. When the decay continues, the hole gets deeper, and eventually reaches the nerve layer under the enamel known as the dentin. This causes painful nerve damage. The death of the tooth occurs when the decay reaches the deepest layer of the tooth (the pulp cavity).