Draw a neat diagram of the "vertical section of a grinding tooth" and label all its important parts. Answer the following questions :

(i) Name the substance which covers the visible portion of the tooth.

(ii) Which of the above labelled parts of the tooth is hard like a bone ?

(iii) Name the substance which covers the embedded part of the tooth.

(iv) What are caries ?

(v) Define plaque.

Diagram of "vertical section of a grinding tooth"

(i) Enamel

(ii) Dentine

(iii) Cement

(iv) The acid produced by the bacteria slowly corrodes the enamel of the teeth and forms cavities known as caries

(v) Sometimes the sugary or starchy foods that we eat get stuck to the teeth. This along with bacteria on the teeth's surface form a yellow coloured film called plaque.