歯内充填物の除去におけるレシプロファイルとロータリーリトリートメントファイルの有効性

Effectiveness of reciprocating and rotary retreatment files in the removal of endodontic filling material.

抄録

本研究の目的は，レシプロファイル（Reciproc）とロータリーリトリメントファイル（Mtwo retreatment [Mtwo-R]）の根管治療時の充填材除去に対する有効性を比較することである．中根湾曲が20°～40°の下顎大臼歯30本を選択し、レシプロックR25ファイルを用いて根管治療を行った。側方コンデンセーションテクニックと根管シーラーを用いて根管充填を行った．検体は、使用した再治療法（n = 15）により、Reciproc R25ファイル、Mtwo-R 15/.05および25/.05ファイルの2群に無作為に割り付けた。再治療後、標本を縦断し、手術用顕微鏡で10倍の倍率で撮影した。全充填物の残存率、および頸部、中間部、骨端部の各3分の1における残存率を算出した。2群の統計的比較にはStudent t検定を用い、各群内の歯根3分の1間の差の検証には分散分析に続いてTukey検定を用いた。2群間で、再造設後の全充填材の残存率（P = 0.87）および根管3分の1の割合（P > 0.05）に統計学的有意差は認められなかった。両群とも、根尖側3分の1の残存量が有意に多かった（P < 0.05）。この結果から、充填物を除去する効果において、2つのシステムに差はないことが示唆された。

The aim of this study was to compare the effectiveness of a reciprocating file (Reciproc) and a rotary retreatment file (Mtwo retreatment [Mtwo-R]) for the removal of filling material during root canal retreatment. A total of 30 mandibular molars with a mesial root curvature between 20° and 40° were selected and prepared using a Reciproc R25 file. The canals were filled using the lateral condensation technique and a root canal sealer. The specimens were randomly allocated into 2 groups according to the retreatment technique used (n = 15): a Reciproc R25 file or Mtwo-R 15/.05 and 25/.05 files. After retreatment, the specimens were longitudinally sectioned and photographed with an operating microscope under ×10 magnification. The percentage of total remaining filling material and the percentages in the cervical, middle, and apical thirds of the specimens were calculated. The Student t test was used for statistical comparisons of the 2 groups, and the analysis of variance followed by Tukey test was used to verify differences among the root thirds within each group. No statistically significant difference between the 2 groups was detected in the percentage of total remaining filling material (P = 0.87) or the percentage in any of the thirds of the root canals (P > 0.05) after reinstrumentation. In both groups, there was a significantly greater amount of remaining material in the apical third (P < 0.05). The results suggested that there is no difference between the 2 systems in their effectiveness at removing filling material.