42. Why should we brush our teeth?
Teeth are made of hard material and seem impossible to get through.
But bacteria can attack them if there is any food left on or around our
teeth.
This left over food on the teeth begins to form a hard material called
plaque. Bacteria grow in plaque and start to eat away the enamel
layer of the tooth. If this continues, soon a cavity is formed that can
reach into the inner pulp of the tooth, exposing the nerve endings.
This results in a very painful toothache. If the infection reaches the
root, the bacteria attack the bone on which the tooth is set causing an
extremely painful abscess. To prevent teeth from decaying, it is very
necessary to brush them after every meal.
Vì sao chúng ta phải đánh răng?
Răng được tạo thành từ một chất liệu cứng và có vẻ như là
không thể bị thủng. Nhưng các vi khuẩn có thể tấn công
