パワーパルスNd: YAGレーザーを用いた根管内異物除去に関する基礎的検討
1999 年 10 巻 1 号 p. 25-33
詳細
1999 年 10 巻 1 号 p. 25-33
The aim of this study was to investigate Nd: YAG laser's capability of removing canal obstructions.
Twenty four extracted single-human teeth were used in this experiment. After removing the tooth crown, they were randomly divided into three groups: dowel core, gutta-percha, and file removal groups. In the dowel core and gutta-percha removal groups, root canals were cleaned, shaped and obturated with laterally condensed gutta-percha and sealer. Then, in the dowel core removal group, post spaces 7.5 mm in length were created, and dowel cores were placed with glass ionomer cement. The dowel cores were made from an Au-Ag-Paalloy. In the file removal group, a tip of a K file, 3 mm long, was intentionally fractured between the middle and apical third of the root canal.
Nd: YAG laser (output energy: 900mJ 10pps) irradiation with an optical fiber (∅=400μm) vwas performed in water to remove dowel cores, gutta-percha and K files from the root canal, and the laser irradiation time was counted. In addition, contact-micro-radiographs were taken before and after the laser irradiation, and the rate of postoperative increase in the root canal area was evaluated.
The results were as follows:
1. Nd: YAG laser was able to remove dowel cores and gutta-percha from the root canal. In 5 out of 8 cases, files were successfully removed from the root canal in the file removal group.
2. The irradiation time of Nd: YAG laser in the dowel core, gutta-percha, and file removal groups was, 670 (±345), 19 (±8), and 317 (±220) sec, respectively.
3. The rate of postoperative increase in the canal area of the dowel core, gutta-percha, and file removal groups was, 28, 6, and 62%, respectively.
