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Factors affecting the long-term results of endodontic treatmentの

根管治療の手技と細菌学的コントロール

になります。

Original Endodontic Procedure

All treatments were performed with a rubber dam and　aseptic technique. The tooth, the clamp, and the rubber dam　were cleansed with 30% hydrogen peroxide solution and then　swabbed with a 5% tincture of iodine. The pulpectomies were　performed with Hedstrom files under local anesthetic.The　widening and shaping of the canals were done with a stepback　technique. Thin K files were used initially in nonvital　cases. Subsequently Hedstrom files were used to widen and　shape the canals. During the preparation, the canals were　frequently irrigated with 0.5% sodium hypochlorite solution.In the vital cases efforts were made to leave an apical pulp　stump of about 2 mm in length. The pulp was completely　removed in cases in which there was necrosis in the coronal　part. In cases where the apical foramen was not indentifiable　on radiographs,the canals were reamed to a level of 1-mm　short of the root apices. When previously root-filled teeth　were retreated, the root fillings were softened with chloroform　and removed with files.　Calcium hydroxide was used as an intracanal dressing　between appointments in the majority of cases (20). Potassium　iodide (2%, 5%) and comphorated phenol were used in　some cases. The access cavities were sealed with zinc oxideeugenol　cement. All root canals were filled with gutta-percha　using the lateral condensation technique. The master cone　was adapted to the canal by dipping it in rosin chloroform,　and then multiple accessory cones were laterally condensed　after having been softened in chloroform. The treatments　were all performed by undergraduate students under the　supervision of experienced endodontists.

Bacteriological Control

In all nonvital and pulpitis cases, the effect of the antiseptic　treatment was bacteriologically controlled. A liquid thioglycolate　medium (11260; Baltimore Biological Laboratories,Cockeysville, MD) supplemented with agar was used (21). This medium is highly effective in reducing oxygen and no　toxic intermediates of oxygen accumulate in the medium　even if it is exposed to atmospheric oxygen for a short while　(22). Furthermore, the agar of the culture medium prevents　any oxygen to which the medium might be exposed during　the sampling procedure from diffusing deeply into it. This　medium has proven to be very successful for transport and　initial subculture of samples taken from root canals (21). The　root canals were filled when a sample cultivated for at least 7　days did not show any bacterial growth.

全ての治療はラバーダム下で無菌的に行われた。

抜髄は局麻下でHファイルを使用し、 ステップバック法で拡大・形成が行われた。

拡大形成中は0.5％ヒポクロで度々洗浄された。

一方、失活歯では細いKファイルが最初に使われ

続いてHファイルで拡大形成が行われた。

生活歯では根尖2mｍまで拡大され

歯冠側に壊死があった場合には完全に歯髄が除去された。

Ｘ線写真で解剖学的根尖が特定できない場合、根管は根尖1mmアンダー部分まで拡大・形成された。

再根管治療歯の根充材はクロロホルムで軟化され、ファイルで除去された。

根充は全てガッタパーチャーポイントを用いて側方加圧された。

治療は全て専門医の監督の下大学生によって行われた。

細菌培養で用いた寒天培地は酸素を減少させるのに有効で

例え大気中の酸素に少しの間曝されても酸素の蓄積による毒性はなかった。

根管は、サンプルを少なくとも7日間培養し

どの細菌も全く成長しなかった場合に根充された

ということです。