アブストラクト(27巻1号:神奈川歯学)

神奈川歯学

Japanese

Title : 電気的根管長測定法の測定精度向上についての研究
Subtitle : 原著
Authors : 山本昭夫, 安田英一
Authors(kana) :
Organization : 松本歯科大学歯科保存学第二講座
Journal : 神奈川歯学
Volume : 27
Number : 1
Page : 93-114
Year/Month : 1992 / 6
Article : 原著
Publisher : 神奈川歯科大学学会
Abstract : 「緒言」根管治療の三大原則として根管の徹底的な清掃拡大, 根管の消毒, 気密な根管充填が挙げられており, これが根尖歯周組織を傷害することなく, 十分に行われて始めて良好な予後が約束される. これを遂行するにあたり, 基本的に重要な事項の1つに根管長の正確な測定がある. 世界で最も広く使用されている方法は, 根管内に測定針を挿入してX線写真を撮影することによって, 根管長を算出する方法であるが, この方法は根尖孔の開口位置が必ずしも根尖端でないことや, 根の湾曲などの影響により, 正確に測定できるとは限らないし, また患者のX線被曝量を増加させる. わが国では1958年歯根膜と口腔粘膜間のインピーダンス値が, ほぼ一定(6.5KΩ)であるとの鈴木の示唆に基づいて, 砂田が直流を用いる根管長測定器を開発した. その後, 直流は測定時に分極を生じ測定が難しい欠点があり, この欠点を克服するために交流を用いる根管長測定器が開発された.
Practice : 歯科学
Keywords : 電気的根管長測定, ルートキャナルメーター, エンドドンティックメーター

English

Title : Improving the Precision of the Electronic Method of Determining Root Canal Length
Subtitle :
Authors : Akio YAMAMOTO, Eiichi Yasuda
Authors(kana) :
Organization : Department of Endodontics and Operative Dentistry, Matsumoto Dental College
Journal : Kanagawa Shigaku
Volume : 27
Number : 1
Page : 93-114
Year/Month : 1992 / 6
Article : Original article
Publisher : Kanagawa Odontological Society
Abstract : Abstract: The purpose of this study is to determine what considerations are necessary to ensure the accurate measurement of root canal length when using an electronic measuring de-vice in the clinic. The following summarizes the detailed evaluations made, and the results obtained, using a hand-held reamer (Zipperer, Pierce) as the measuring probe in conjunction with two electronic root canal length measuring instruments, the Root Canal Meter (RCM) and Endodontic Meter (EM), both made by Onuki Dental Co., Ltd., (Tokyo, Japan). 1. When the reamer tips were extruded through a soft rubber plate into the NaCl solution, penetrations of approximately 0.25mm to 0.5mm were required for reamer sizes #25 through #40 to reach a meter reading value of 40. 2. The following experiments were performed in order with freshly extracted vital teeth (60 teeth totaling 74 roots). 1) With the root immersed in a saline solution, a #15 reamer was introduced into the canal up to a point 2 mm short of the apical foramen, and the meter value was read. 2) The apical foramen was covered with wax, and the procedure of 2-1) was repeated. 3) The canal was then prepared to a point 2 mm short of the anatomical foramen, the meter values were read with a final reamer inserted into the canal. It was found through these experiments that larger meter values were obtained the deeper the reamer tip was inserted into the canal, and the deeper the root was immersed in the NaCl solution, and measuring current was flowed through the canal walls. 3. The following experiments were performed with in situ vital teeth (38 teeth having 48 canals) and non-vital (43 teeth having 55 canals). A reamer tip was inserted into the canal until the meter read 40. The reamer was then immobilized with composite resin, and the tooth sectioned to show the position of the reamer tip in the apical structure. In cases where the reamer tip fit tightly against the root canal walls near the apical constriction, the distance from the tip to the apical foramen fell within a limited range. When expressed with positive values in the direction of the periodontal membrane and negative values toward the root canal orifice, this distance averaged +0.50 +- 0.22mm for the RCM with vital teeth and +0.50 +- 0.17mm with non-vital teeth, and + 0.47 +- 0.16mm for the EM with vital teeth and +0.39 +- 0.20mm with non-vital teeth. These findings support the conclution that accurate measurment of root canal length using the RCM or EM requires the following conditions. 1. Electrolytic materials such as pulp tissue or necrotic materials should first be removed as completely as possible. 2. A reamer that was at least 3 sizes greater than enough to produce a feeling of resistance from contact with the canal walls near the apical constriction should then be inserted until the meter shows a value of 40. Since the reamer tip will extrude at this time into the periodontal membrane approximately 0.5mm beyond the apical constriction, the working length should be set to 0.5mm shorter than the length for which the meter reads a value of 40.
Practice : Dentistry
Keywords :