Purpose: to establish the existence and orientation of dentinal tubules at the level at which resection is normally performed.
N= 22 teeth (1st : 10 ant. Teeth unknown ag / 2nd: age (35-81y)
•Apicectomy done in 1st gp at al level 2-4 mm from the apex, while in 2nd gp was 3mm at an angle of 45-60°.
•The cut root face was examined under the scanning electron microscope (SEM) at 3 locations, i.e. close to the root canal, about half-way between the canal and the (CDJ) and just inside the dentine-cementum junction.
•The number of tubule orifices per square millimeters was calculated.
Most highlighted Results:
•1st group: superficial tubules could be seen to communicate with the root canal at their proximal ends with the external surface at their peripheral ends (fig.2).
•At a point approximately 3 mm from the apex, and half-way between the root canal and CDJ, the average number of tubules was 27,000 tubules per mm2.
•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.
• Older teeth also displayed large numbers of tubules.
the angle of the beveled root face should be kept to a minimum, and the retrograde root filling should extend back into the canal at least to the level of the coronal end of the bevel.