Number of tubules per unit area: (A) Is 2 times more at pulpal end, (B) Is 3 times more at pulpal end, (C) Is 4 times more at pulpal end, (D) Is 5 times more at pulpal end
Answer is C. The number of tubules per unit area is more at the pulpal end by 4 times than at their terminal end. Hence the intertubular dentin is well appreciated at the terminal end. The tubules generally have a doubly convex course, the primary curvature (often called ―S‖ shaped tubules), the first convexity of which is directed towards apex.