根管内吸引洗浄法のための吸引針の開発 4852007 年 8 月

Intracanal Aspiration Technique for Root Canal Irrigation

Part 2.　Development of Newly Designed Aspiration Needles

FUKUMOTO Yasue, FURUHATA Kazuto, YOSHIOKA Takatomo and SUDA Hideaki

Pulp Biology and Endodontics, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University

（Chief：Prof. SUDA Hideaki）

　Abstract: We have developed a new root canal irrigation system: intracanal aspiration technique（IAT）, where irrigants are aspirated through a needle positioned near the apical canal end. The application of IAT was limited to

wide canals because 24　G standard needles were used. The aim of this study was to develop newly designed aspira-tion needles for narrower canals in IAT.　In Study 1, two types of newly designed aspiration needles with a tip diameter of 27　G were used. The size of the basal part of Type 1 and 2 needles was equivalent to 21 and 23　G, respectively. Twenty-one root canals were instru-mented to #35 file size, and divided into three groups（Groups 1－3）of 7 teeth each. Seven root canals（Group 4）were instrumented to #50 file size. The roots were fixed in a plastic case and surrounded with normal saline agar colored by 1％ acid red solution. In Groups 1, 2 and 4, each root canal was irrigated using IAT with aspiration needle of Type 1, 2 and 24　G, respectively. Each needle was connected to a Root ZXTM娯 and positioned 2 mm from the apical root end. In Group 3, root canals were irrigated conventionally. Each canal was irrigated with 9 m l of 14％ EDTA for 3 minutes, and then with 6 m l of 6％ NaClO for 2 minutes. The meter value of Root ZXTM娯 during irrigation and the discolored area of agar around the apical root end were measured.　In Study 2, the flow rate at －20 kPa was measured with newly designed aspiration needles of 24　G and 27　G.　In Study 1, indicated meter values of Root ZXTM娯 for Groups 1, 2 and 4 were significantly closer to the apex than those of Group 3（p＜0.05）. Discolored areas in Groups 1, 2 and 4 were significantly smaller than those of Group 3 （p＜0.05）. The results of Study 2 suggested that the optimal needle for IAT may consist of a 23　G basal part of 32.5 mm in length and 27　G tip part of 5 mm in length.　It was concluded that the newly designed aspiration needles for IAT could be effective in the canal with the small apical diameter of 0.35 mm.

　Key words: Root canal irrigation, Intracanal aspiration technique, Aspiration needle