Question

When a person eats sugary food, then organisms A present in his mouth act on sugar to produce a substance B. The substance B first dissolves the calcium salts from the top part C of the tooth and then from its middle part D forming holes E. These holes ultimately reach the part F in the lower part of tooth which contains nerves and blood vessels. The substance B irritates the nerve endings inside the tooth causing toothache.

1. What are (i) organisms A, and (ii) substance B?
2. What are (i) part C, and (ii) part D, of tooth known as?
3. By what name are the holes E in the tooth known?
4. Name the part F of the tooth.
5. What will happen if organisms A reach part F of the tooth known?

Answer 1

(a)

1. Organisms A: Bacteria (such as Streptococcus mutans).
2. Substance B: Acid (primarily lactic acid produced by bacteria fermenting sugars).

(b)

1. Part C: Enamel (the hard, outermost protective layer of the tooth).
2. Part D: Dentin (the yellowish, bone-like layer directly beneath the enamel).

(c) Holes E are known as Cavities (or Dental Caries).

(d) Part F is known as the Pulp cavity (or simply the Pulp).

(e) If the bacteria (Organisms A) break through the dentin and manage to reach the pulp cavity (Part F), the following will happen:

• Severe Infection and Inflammation: The bacteria will infect the living tissues, blood vessels, and nerves inside the pulp, causing a condition known as pulpitis.
• Intense Pain: The resulting inflammation builds up high pressure inside the sealed tooth, leading to severe, throbbing toothaches.
• Abscess Formation: If left untreated, the infection can kill the nerve, travel down to the root tip, and form a painful collection of pus called a tooth abscess, which typically requires a root canal treatment or tooth extraction.