スミア層除去に及ぼす超音波照射剤の活性化の効果

Effect of Ultrasonic Activation of Irrigants on Smear Layer Removal.

抄録

はじめに:

本研究の目的は、17％EDTAおよび1％NaOCl溶液を用いた受動的超音波洗浄（PUI）が塗抹層除去に及ぼす効果を評価することである。

INTRODUCTION: The objective of this study was to evaluate the efficacy of passive ultrasonic irrigation (PUI) with 17% EDTA and 1% NaOCl solutions on smear layer removal.

方法:

32本のヒトの歯の根管形成をProTaperシステムで行った。次に、走査型電子顕微鏡を用いて歯頸部、中間部、根尖部の3分の1のスメア層形成を定量化できるように、歯を縦方向に破折した。破折した歯牙を再組立した後、最終的な潅注プロトコルの違いにより4群に分けた：第1群：EDTA＋NaOCl、第2群：EDTA＋PUI＋NaOCl、第3群：EDTA＋NaOCl＋PUI、第4群：EDTA＋NaOCl＋PUI。潅注後、同じ部位を走査型電子顕微鏡で撮影できるように歯の半分を分離し、潅注した部位の開口した象牙細管の総面積に対する割合を求めた。結果は、Kruskal-Wallis、分散分析、およびBonferroni検定（α = 0.05）に供した。

METHODS: Root canal preparations of 32 human teeth were performed with the ProTaper system. Next, they were longitudinally fractured to permit quantitation of smear layer creation from the cervical, middle, and apical thirds of the roots by using scanning electron microscopy. After reassembling the fractured tooth halves, they were divided into 4 groups according to different final irrigation protocols: group1, EDTA + NaOCl; group 2, EDTA with PUI + NaOCl; group 3, EDTA + NaOCl with PUI; and group 4, EDTA + NaOCl, both with PUI. After irrigation, the tooth halves were separated to permit imaging the same areas by scanning electron microscopy, and a percentage of opened dentinal tubules in irrigated areas as a percent of the total area was obtained. The results were submitted to Kruskal-Wallis, analysis of variance, and Bonferroni tests (α = 0.05).

結果:

全群の検体において、歯頸部3分の1では塗抹層の除去率および開存歯管面積の割合が高く、次いで中間部3分の1、先端部3分の1の順であった。潅注群のうち、第2群と第4群では歯頸部3分の1の塗抹層除去率が最も高く、最も低かった。

RESULTS: The cervical third of the samples from all groups showed higher percentage of smear layer removal and open dentinal tubule areas, followed by the middle and apical thirds. Among the irrigation groups, there were statistically significant differences in cervical third between group 2 and group 4 samples, with the highest and lowest percentage of smear layer removal, respectively.

結論:

1％NaOClを使用し、超音波チップを骨端孔から1mm以内に設置するPUIは、従来の灌流と比較して、塗抹層除去において高い有効性を示さなかった。

CONCLUSIONS: PUI by using 1% NaOCl and ultrasonic tip placed within 1 mm of the apical foramen did not show higher efficacy in smear layer removal compared with conventional irrigation.