Q. 69 B3.7( 11 Votes )
What is meant by dental carie ? How are they caused?
Dental caries is tooth decay which is caused by the action of acid forming bacteria and improper dental care. It is most common form of oral disease.
It generally happens when we eat sugary food. Such food, when acted upon by the bacteria in the mouth, produces acids. The acids, thus produced, lead the loss of calcium and phosphate from the enamel and, subsequently, from the dentine which leads to cavities in the tooth.
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When a person puts food in his mouth, then teeth cut it into small pieces, chew and grind it. The glands A in the mouth secrete a substance B which is mixed with the food by tongue. The substance B contains an enzyme C which starts the digestion of food in the mouth. The slightly digested food from the mouth goes down a tube D. The special type of movements E in the walls of tube D push the food into stomach for further digestion. The stomach wall secretes gastric juice containing three substance F, G and H. One of the functions of F is to kill bacteria which may enter the stomach with food. The substance G protects the inside layer of stomach from the damaging effect of substance F whereas substance H is an enzyme for digestion. The partially digested food then enters into small intestine for further digestion.
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(ii) substance B, and (iii) enzyme C?
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