Dentinal tubules at the root ends of apicected teeth: a scanning electron microscopic study.

Two groups of teeth, one of which contained teeth of known age, were examined by scanning electron microscopy to ascertain the presence of a potential pathway for leakage at the root ends of apicected teeth. At a point approximately 3 mm from the apex, a level chosen as being typical for apicectomy, and half-way between the root canal and the dentine-cementum junction, there were found to be, on average, 27,000 tubules per mm2. Older teeth also displayed large numbers of tubules. Close to the dentine-cementum junction, an area which may communicate with the root canal even in the presence of a retrograde root filling, an average of 13,000 tubules per mm2 were found.