アブストラクト(23巻4号:神奈川歯学)

神奈川歯学

Japanese

Title : 根管治療用超音波装置の切削特性について
Subtitle : 原著
Authors : 畑宏幸, 長田保
Authors(kana) :
Organization : 神奈川歯科大学歯科保存学教室第三講座
Journal : 神奈川歯学
Volume : 23
Number : 4
Page : 587-597
Year/Month : 1989 / 3
Article : 原著
Publisher : 神奈川歯科大学学会
Abstract : 「緒言」根管治療における根管の機械的拡大清掃は, 根管内の感染象牙質, 壊死物質ならびに, 細菌等の起炎性物質の除去にかかせない操作であり, 適正な根管の拡大形成は根管処置の仕上げにあたる根管充填を確実かつ容易ならしめるものである. この根管の機械的な拡大形成には, 手用のリーマーやファイルによる操作が一般的である. しかしながら, 手用の根管拡大用器具を用いた根管拡大形成術式は, 煩雑な操作で, 多大な労力を必要とし治療時間を長引かせる一要因となっている. このようなことから, 根管の拡大清掃を効率良く行うために根管用器具を歯科用電気エンジンに取り付けて根管拡大を行う方法が考案されている. これらのうちで, エンジンリーマーは, 同一方向の回転のために, リーマー破折を起こしやすく, また, ジロマチックならびにレーサーコントラは, 根管壁面の滑沢化を図ることが難しく, 根管壁にレッジを形成しやすい. さらに, 切削片による刃部の目づまりが生ずる等の欠点の他, 切削効果が手用の根管拡大器具を使用した場合よりも劣るとの報告もある.
Practice : 歯科学
Keywords : 超音波振動,根管の拡大形成, 超音波ファイルの切削特性

English

Title : A Study on the Mechanical Characteristics of Ultrasonic Device for Root Canal Treatment
Subtitle : Original article
Authors : Hiroyuki HATA, Tamotsu Osada
Authors(kana) :
Organization : Department of Conservative Dentistry, Kanagawa Dental College
Journal : Kanagawa Shigaku
Volume : 23
Number : 4
Page : 587-597
Year/Month : 1989 / 3
Article : Original article
Publisher : Kanagawa Odontological Society
Abstract : Abstract : Recently, many studies have demonstrated the superiority of the ultrasonic devices in endodontic treatment, while other reports did not recpgnize the advantage of the ultrasonic instrumentation over hand instrumentation. This disagreement in opinion might be due to the fact that the mechanical characteristics of ultrasonic devices have not been clarified. Therefore, some factors which might contribute to the mechanical characteristics of ultrasonic device for root canal treatment were examined. These factors were : (a) applied force on file ; (b) angle of connector ; (c) position of substrate material being cut ; (d) filing speed ; and (e) resonance of file. These factors were examined by measuring the cutting depth on acrylic wafer using the cutting efficiency testing apparatus. This apparatus with a push-pull stroke approximately 4 min in length, was propelled the root canal instruments in linear motion. The filing speed was adjusted to 100 strokes per minute. The results were as follows : 1. The greater load was given to the file, the higher was the cutting ability of ultrasonic device. But cutting efficiency of #15, #25 and #35 files were inhibited over the load of 50, 60 and 70g each. It was considered that the adequate load for filing utilized ultrasonic device was #15 : 50g, #25 : 60g and #35 : 70g. 2. The file attached to the angled connector had a cantilevered vibration. And the cutting ability was effected by connector angle. The 120°-type connector was more effective than straight type (180°-type connector). 3. Substrate materials were made deeper cut when it was applied against the vibrating direction of the file than were applied at right angle to vibrating direction of the file. 4. Cutting efficacy of ultrasonic device was evaluated under the conditions as filing speed of 25, 50 and 100 strokcs/min by comparing each ratio of cutting depth per total number of filing strokes after 20 minutes. The ultrasonic vibration showed tigher cutting ability when this ultrasonic device was operated 25 strokcs/min. 5. Cutting efficiency of two methods was examined under the same amplitude. One was to set up the file length slightly shifted from the resonance point and to give the amplitude to file using resonance phenomenon. The other was to set up the file length of nonresonance condition and to give the amplitude by power supplying from the device. The latter showed higher cutting ability without the risk of the file fracture. For clinical use, it was desirable that light, slow, push-pull strokes were applied along the canal walls while moving the device circumferentially. The ultrasonic device shoud be controlled by power supplying, with file length of nonresonance condition, to prevent the file fracture.
Practice : Dentistry
Keywords :