Endodontic Treatment II

The canal configuration of 75 extracted mandibular second molars was categorized using radiographs from two directions with files in place at working length. One tooth (1.3%) had a single canal, and two teeth (2.7%) were C shaped. In the mesial root, 3 teeth (4%) were type I, 39 teeth (52%) were type II, and 30 teeth (40%) were type III. In the distal root, 64 teeth (85.3%) had a type I system, 7 teeth (9.3%) had a type II, and 1 tooth (1.3%) had type III.

Seventy-five extracted second molars were used in this investigation, all obtained from oral surgeons in the Chicago area and all identified as such at the time of extraction. The teeth were placed into a 5.25% solution of sodium hypochlorite immediately after extraction and stored for several weeks. Preoperative radiographs were taken from straight and angled views in order to gain some clue as to the configurations present (15). Access cavities were prepared for each tooth according to Weine (15), bearing in mind the expected configuration as divulged by the radiographs. The floors of the chambers were examined carefully for all orifices. Working lengths were estimated by measuring the teeth with an endodontic ruler, and size no.10 or no.15 files were placed into the mesial canal(s); and size no.15, no.20, or no.25 files were placed into the distal canal(s) at the estimated working lengths. Many of these initial file placements were found to be at slightly incorrect positions when the radiographs were viewed, but this procedure was followed as it would be in a clinical case.