皆さんこんにちは。
今回は根管の形態に関する文献です。
6本の上顎大臼歯を用いて、3種類の根管器具を用いた
機械的拡大による根管形態の変化を
CTで比較しています。
Root canal morphology changes during canal preparation, and these changes may vary depending on the technique used. Such changes have been studied in vitro by measuring cross-sections of canals before and after preparation. This current study used nondestructive high-resolution scanning tomography to assess changes in the canals’ paths after preparation. A microcomputed tomography scanner (cubic resolution 34 microm) was used to analyze 18 canals in 6 extracted maxillary molars. Canals were scanned before and after preparation using either K-Files, Lightspeed, or ProFile .04 rotary instruments. A special mounting device enabled precise repositioning and scanning of the specimens after preparation. Differences in surface area (deltaA in mm2) and volume (deltaV in mm3) of each canal before and after preparation were calculated using custom-made software. deltaV ranged from 0.64 to 2.86, with a mean of 1.61 +/- 0.7, whereas deltaA varied from 0.72 to 9.66, with a mean of 4.16 +/- 2.63. Mean deltaV and deltaA for the K-File, ProFile, and Lightspeed groups were 1.28 +/- 0.57 and 2.58 +/- 1.83; 1.79 +/- 0.66 and 4.86 +/- 2.53; and 1.81 +/- 0.57 and 5.31 +/- 2.98, respectively. Canal anatomy and the effects of preparation were further analyzed using the Structure Model Index and the Transportation of Centers of Mass. Under the conditions of this study variations in canal geometry before preparation had more influence on the changes during preparation than the techniques themselves. Consequently studies comparing the effects of root canal instruments on canal anatomy should also consider details of the preoperative canal geometry.
つまり
どんな根管器具を使用したかよりも
根管オリジナルの形態そのものの方が
機械的拡大によって根管を変形させる
影響力がより大きいと述べられています。
その為、術前のX線写真の読影力や手指感覚を鍛えて
根管の3次元的な形態をイメージすることが
重要だと思いました。
引用文献
Peters OA, Laib A, Göhring TN, Barbakow F.
Changes in root canal geometry after preparation assessed by high-resolution computed tomography.
J Endod. 2001 Jan;27(1):1-6.