Analysis of Endodontic Failure of C-shaped Root Canals

Analysis of Cause of Endodontic Failure of C-Shaped Root Canals.

抄録

本研究の目的は，C型根管のさまざまな特徴や分類を分析し，切除した根面を歯内療法用顕微鏡と走査型電子顕微鏡（SEM）で観察することにより，C型根管の歯内障害の原因を評価することである．本研究では，C型根管を有する42本の歯が対象となり，意図的な再植手術が行われた。手術前には，歯周X線撮影とコーンビームCT撮影を行った．根管の形状を分析し，Meltonの分類に基づいて冠側と先端側で分類した．1:100,000のエピネフリンと2%のリドカインを注射した後，歯を慎重に抜去した。歯根端切除後，切除した歯根面を手術用顕微鏡とSEMで観察した。下顎第二大臼歯が最も多く（90.4％）を占めていた。最も多く観察された根管形態は，冠状のC1（45.2%）と先端3mmのC3（45.2%）であった。C型根管治療が失敗した原因は，漏洩根管が最も多く（45.2％），次いで地溝（23.8％），欠損根管，過充填，異所性問題であった。結論として，C型根管は下顎第二大臼歯に最も多く見られた。失敗の原因で最も多かったのは，漏れた根管とイスマスであった。

The purpose of this study was to analyze various characteristics and classification of C-shaped root canals and evaluate the causes of endodontic failure of C-shaped root canals by examining the resected root surface with an endodontic microscope and a scanning electron microscope (SEM). Forty-two teeth with C-shaped root canals were included in this study and had undergone intentional replantation surgery. Before surgery, periapical radiography and cone-beam computed tomography were taken. The root canal configuration was analyzed and classified according to Melton's classification at coronal and apical level. After injection of 1 : 100,000 epinephrine with 2% lidocaine, the tooth was carefully extracted. After the root-end resection, the resected root surface was examined using an operating microscope and SEM. Mandibular second molars were most frequently involved teeth (90.4%). The most frequently observed root canal configurations were C1 at the coronal level (45.2%) and C3 at the apical 3 mm level (45.2%). The most common cause of failure for a C-shaped root canal treatment was a leaky canal (45.2%), followed by an isthmus (23.8%), missing canal, overfilling, and iatrogenic problems. In conclusion, C-shaped root canals were most frequently found in mandibular second molars. The most common cause of failure was a leaky canal and isthmus.