Which of the following is indicative of ageing?

 # Which of the following is indicative of ageing?

A. Expression of dead tracts

B. Widening of predentin

C. Increase in tubular diameter

D. Increase in peritubular dentin

The correct answer is A. Expression of dead tracts. 

It is rather difficult to separate age and functional changes in dentin. Dentin is laid down throughout life. This dentin is termed secondary dentin. If dentin forms as a result of pathological process, like caries, it is termed tertiary dentin. Tertiary dentin shows irregularity in size, shape, number and arrangement of dentinal tubules. Dentinal tubules degenerate due to injury resulting in the formation of dead tracts. Mineralization of dentinal tubules results in the formation of sclerotic dentin. This makes the tooth to appear transparent in these areas.

Reference: Orban's Oral Histology and Embryology