Abstract
Experiments were conducted on ten human maxillary anterior teeth, extracted for the purpose of assessing the cleansing effects of root canals, using a new style perforated standard needle. Another five teeth, which were reamed and filed after 10% NaOCl was instilled using a conventional syringe in the root canal, were examined as a control. Enlarging and cleansing of the root canal was conducted by the same procedures for both the control and experimental groups. Following this, two ml of 10% NaOCl was instilled using the new style needle and was left alone for three minutes, and two ml of 15% EDTA was also instilled into the root canal, in the experimental group. The materials obtained by these procedures were examined under scanning electron microscopy. The method, in which the root canal was filled with 10% NaOCl using a conventional syringe, and enlarged by a reamer and a K-type file, proved insufficient for cleansing the root canal. Pulp tissues, dentin chips and smeared layers were observed on the root canal walls. However, when two irrigating solutions were mutually instilled using this needle in the root canal, then left alone for three minutes, pulp remnants, dentin chips and smeared layers were effectively removed from the root canal walls. These findings indicate that the irrigating solutions are able to penetrate into the apical area of the root canal, when the new style perforated needle is added to the conventional procedures ; however, solutions were unable to reach this area by other methods. Thus, a large benefit can be gained when using this needle in endodontic therapy.
