Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt, Endodontic Specialist, Ministry of Health, Alexandria, Egypt.
Endodontics, Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
BMC Oral Health. 2022 Dec 31;22(1):661. doi: 10.1186/s12903-022-02562-y.
This study aims at identifying the microbiota in traumatized immature permanent teeth with periapical lesions using Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).
The study included 16 immature maxillary central incisors with periapical lesions in 13 patients. Field decontamination and negative control samples were performed before and after access cavity preparation. Root canal samples were taken using sterile stainless-steel hand files following field decontamination. In-office inoculation and pure sub-cultures were performed. Bacterial isolates were prepared for MALDI-TOF MS (Bruker, Billerica, MA USA) analysis using the formic acid extraction method. A comparison of the prevalence of isolated microorganisms was done using a one-sample chi-square test. Comparisons between identified microbial species with the, cone beam computed tomography periapical index (CBCT PAI) scores and lesion volume were also conducted. The Chi-square test was applied to investigate the association between the categorical variables .
Out of the forty isolates recovered from the 16 traumatized teeth included in the present study with the mean patients' age of 10.93 ± 1.77, 37 isolates were reliably identified by MALDI-TOF MS. Twelve teeth (62.5%) were polymicrobial. The recovered bacteria belonged to five phyla, 15 genera and 25 species. Firmicutes were the predominant phylum (P < 0.001) over Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria. Gram positive bacteria were significantly more prevalent than Gram negative (p = 0.03). Facultative anaerobes were the most prevalent (P < 0.001) compared to the obligate anaerobes and the obligate aerobes. The latter were the least prevalent. Statistically, significant differences existed in the comparison between CBCT PAI scores according to bacterial gram staining.
Traumatized immature permanent teeth with periapical lesions showed a significant predominance of Gram-positive facultative anaerobes. MALDI-TOF MS provided accurate identification of numerous viable endodontic microbes.
本研究旨在使用基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）鉴定伴有根尖病变的外伤性未成熟恒牙中的微生物群。
本研究纳入了 13 名患者的 16 颗上颌中切牙伴有根尖病变。在制备开髓腔前后进行现场去污染和阴性对照样本。在进行现场去污染后，使用无菌不锈钢手用锉取根管样本。进行门诊接种和纯亚培养。使用甲酸提取法准备 MALDI-TOF MS（Bruker，马萨诸塞州比勒里卡）分析用细菌分离物。使用单样本卡方检验比较分离微生物的患病率。还对鉴定的微生物种类与锥形束 CT 根尖指数（CBCT PAI）评分和病变体积进行了比较。应用卡方检验研究分类变量之间的关系。
在本研究中，从 16 颗受创伤的牙齿中恢复了 40 株分离物，平均患者年龄为 10.93±1.77 岁，其中 37 株分离物通过 MALDI-TOF MS 可靠鉴定。12 颗牙齿（62.5%）为多微生物。回收的细菌属于五个门，15 个属和 25 个种。厚壁菌门（Firmicutes）是优势菌门（P<0.001），其次是拟杆菌门（Bacteroidetes）、变形菌门（Proteobacteria）、放线菌门（Actinobacteria）和梭杆菌门（Fusobacteria）。革兰阳性菌明显多于革兰阴性菌（p=0.03）。需氧菌是最常见的（P<0.001），其次是严格厌氧菌和兼性厌氧菌。后者最少见。根据细菌革兰氏染色，CBCT PAI 评分之间的比较存在统计学差异。
伴有根尖病变的外伤性未成熟恒牙显著优势为革兰阳性兼性厌氧菌。MALDI-TOF MS 可准确鉴定大量有活力的牙髓微生物。
