根尖病変を有する症候性下顎第一大臼歯における根管治療成績を評価した前向きコホート研究

A prospective cohort study evaluating the outcome of root canal retreatment in symptomatic mandibular first molars with periapical lesions.

抄録

目的:

歯根膜病変を有する症候性下顎第一大臼歯の根管治療成績に対する各種予測因子の影響を、最低2年後に評価すること。

AIM: To evaluate the impact of various predictors on the outcome of root canal retreatment in symptomatic mandibular first molars with periapical lesions after a minimum of 2 years.

研究方法:

症候性歯根膜炎または急性歯根膜膿瘍と診断され、局所的な口腔内腫脹を伴う歯根膜病変を有する、過去に根管治療を行った下顎第一大臼歯120本が対象である。根管治療は，経験豊富な歯内療法専門医により，標準化された治療プロトコールを用いて行われた．歯は臨床的およびX線写真的にフォローアップされ，X線写真の結果はmodified periapical index scale（PAI）を用いて評価された．根管治療の累積成功率と予測因子が根管治療成績に及ぼす影響をKaplan-Meier分析とlog-rank検定で分析し、予測因子のハザード比も一変量Cox比例ハザード回帰分析で有意水準5％で調査した。

METHODOLOGY: One hundred and twenty previously root canal treated symptomatic mandibular first molars with periapical lesions which were diagnosed as symptomatic apical periodontitis or acute apical abscess with localized intraoral swelling were included. Root canal retreatment was performed by an experienced endodontist using a standardized treatment protocol. The teeth were followed up clinically and radiographically and the radiographic outcome was assessed using a modified periapical index scale (PAI). The cumulative success proportion and the influence of predictors on the outcome of the root canal retreatment were analysed using Kaplan-Meier analyses and log-rank tests, and the hazard ratios for the predictors were also investigated using Univariate Cox Proportional Hazard regression analysis at a significance level of 5%.

結果:

120 歯のうち、103 歯が再検査を受け、回収率は 85％であった。累積成功率は88％で、そのうち治癒が64％、治癒が24％、失敗率は12％と記録された。年齢，性別，軟組織圧痛，口腔内腫脹，病変の大きさ，PAIスコア，根管治療前の根尖レベル，根管充填密度などの術前予測因子，活発な滲出液排出，根管治療後の根管充填密度，修復物タイプなどの術中予測因子はいずれも根管治療成績に影響しなかった（p＞0.05）．根管治療の成功率を有意に低下させた唯一の要因は，根管充填の根尖レベルであり，根尖開存が確立されていない歯で根管充填がX線写真上の根尖から2mm以上短い場合，成功率は有意に低かった（p＝0.023）．

RESULTS: Of the 120 teeth, 103 teeth were re-examined with an 85% recall rate. The cumulative success rate was 88% in which 64% were healed and 24% were healing, and failure rate was recorded as 12%. None of the preoperative predictors, including age, gender, soft tissue tenderness, intraoral swelling, size of the lesion, PAI score, apical level and density of root canal filling before root canal retreatment, nor intraoperative predictors, such as active exudate drainage, density of root canal filling after root canal retreatment and restoration type had an influence on the outcome of root canal retreatment (p > .05). The only factor that significantly reduced the success rate of root canal retreatment was the apical level of the root canal filling; when it was more than 2 mm short of the radiographic apex in teeth where apical patency was not established, the success was significantly lower (p = .023).

結論:

歯根周囲病変を有する症候性下顎第一大臼歯に対する根管治療では，88%の成功率が得られた．予測因子は，根管治療後の根管充填の先端レベルを除いて，いずれも治療結果に大きな影響を与えず，根管充填が短いと治療後の歯内療法疾患が有意に多くなることが示された．

CONCLUSIONS: Root canal retreatment in symptomatic mandibular first molars with periapical lesions resulted in a success rate of 88%. None of the predictors had a significant influence on the outcome, except for the apical level of the root canal filling after root canal retreatment with short root fillings being associated with significantly more post-treatment endodontic disease.