超音波振動による根管拡大, 清掃法の走査電顕的評価

Abstract

Experiments were conducted on ten human maxillary anterior teeth, extracted for the purpose of comparing the effects of hand instrumentation, and those of a combination of this technique with ultrasonic vibration, in the enlargement and cleansing of the root canal. The results obtained by these two diverse procedures examined by SEM. In the enlargement and cleansing of the root canal wall conducted by conventional hand instrumentation, the openings to the dentinal tubule were obscured by a thick smeared layer for all of the three regions, the coronal, middle and apical regions, of the root canal walls. In the observation of the root canal wall under low magnification, better results were observed with a combination of the techniques than with hand instrumentation only. When observations were made on the root canal walls in the apical area, however, no difference was observed between the two procedures ; the apical area of root canal walls, which was the part most crucial in the prognosis of root canal treatment, was covered with a smeared layer even in the experiment using a combination of the techniques. These results indicate the necessity of the development of effective methods for removing the smeared layer from the region treated.