根管治療後の根尖周囲病変および歯冠漏出と関連する培養可能な微生物叢：予備的研究

Cultivable microbial flora associated with persistent periapical disease and coronal leakage after root canal treatment: a preliminary study.

抄録

目的:

根尖周囲病変が持続する根充歯において培養可能な細菌叢を同定し、in vitroサンプリングプロトコルを用いて根管系内の分布を特定すること。

AIM: To identify the cultivable bacterial flora in root filled teeth with persistent periapical lesions and to locate their distribution within the root canal system using an in vitro sampling protocol.

方法:

Eastman Dental Hospitalの口腔顎顔面外科で、抜歯したばかりの根充歯8本を採取した。7本の歯は根尖性歯周炎が持続し、歯冠漏出が認められた。抜歯後すぐに嫌気チャンバーに移し、歯冠部（1例を除くすべて）と2つの歯根部（歯冠部と歯根端部）を横方向に切開した。それぞれのセグメントから2つのサンプルを採取し、1つは象牙質から、もう1つは修復物またはガッタパーチャ（GP）根充から採取した（合計46部位）。サンプルを分散し、連続希釈し、血液寒天培地と潔癖性嫌気性寒天培地（5％脱脂ウマ血液）で培養した。一次増殖した菌は、純粋な分離株を得るために再培養され、日常的な微生物学的手法と市販の酵素検査によって同定された。

METHODOLOGY: Eight freshly extracted root filled teeth were collected from the Oral and Maxillo-facial Surgery Department, Eastman Dental Hospital. Seven teeth were associated with persistent apical periodontitis and also showed evidence of coronal leakage. Teeth were transferred to an anaerobic chamber immediately after careful extraction and sectioned transversely to give a crown (in all but one case) and two root segments (coronal and apical). Two samples were obtained from each segment, one from dentine and the other from the restoration or gutta-percha (GP) root filling (46 sites in total). The samples were dispersed, serially diluted and cultured on blood agar and fastidious anaerobic agar (with 5% defibrinated horse blood). The primary growth was subcultured to obtain pure isolates, which were identified by routine microbiological techniques and commercial enzyme tests.

結果:

すべての歯から合計252株が分離された。最も多く分離された細菌はグラム陽性の通性嫌気性菌で189/252株（75％）、ブドウ球菌（48/252株、19％）、連鎖球菌（44/252株、17％）、腸球菌（20/252株、8％）、放線菌（20/252株、8％）がほとんどの歯で検出された（それぞれ6/8、6/8、5/8、5/8、7/8）。偏性嫌気性菌（17％）のうち、ペプトストレプトコッカス（7％）もほとんどの歯（7/8）に存在した。細菌叢と部位（歯冠/歯根/歯根端）または表面（歯科用/GP/修復物）との統計的関連性は示されなかった。

RESULTS: A total of 252 strains were isolated from all the teeth. Of all the isolates, the most prevalent bacteria were Gram-positive facultative anaerobes 189/252 (75%) with staphylococci (48/252, 19%), streptococci (44/252, 17%), enterococci (20/252, 8%) and Actinomyces species (20/252, 8%) being found in most of the teeth (6/8, 6/8, 5/8, 5/8 and 7/8, respectively). Of the obligate anaerobes (17%), peptostreptococci (7%) were also present in most teeth (7/8). A statistical association between bacterial flora and site (crown/coronal/apical) or surface (dental/GP/restoration) could not be shown.

結論:

根尖性歯周炎と歯冠漏出が持続する根充歯における優勢菌群はグラム陽性通性嫌気性菌であり、ブドウ球菌、連鎖球菌、腸球菌の順であった。

CONCLUSIONS: The predominant group of bacteria in root filled teeth with persistent apical periodontitis and coronal leakage was Gram-positive facultative anaerobes of which staphylococci followed by streptococci and enterococci were the most prevalent.