Conservative and MI Dentistry (including Endodontics), King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, United Kingdom; Centre for Oral, Clinical and Translational Sciences, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London, United Kingdom.
Centre for Host Microbiome Interactions, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, United Kingdom.
J Endod. 2021 Mar;47(3):415-423. doi: 10.1016/j.joen.2020.12.009. Epub 2020 Dec 23.
Previous studies have shown that in teeth presenting with symptoms of irreversible pulpitis (IP), bacteria and their by-products driving inflammation are confined mainly within the coronal pulpal tissue. The present study aimed to determine the presence and identity of bacteria within pulps presenting with clinical symptoms of IP using molecular methods.
Samples were obtained from 30 adult patients presenting to the dental emergency department with signs and symptoms of IP. After meticulous surface decontamination, the pulp space was accessed, and clinical samples were collected from inflamed pulp tissue using sterile paper points. Genomic DNA was extracted from the clinical samples, and quantification of bacteria was performed using quantitative polymerase chain reaction targeting the conserved 16S ribosomal RNA (rRNA) gene. To characterize the microbial composition, the V3-V5 hypervariable regions of the 16S rRNA gene were amplified and subjected to next-generation sequencing on the MiSeq platform (Illumina, San Diego, CA).
Of the 30 teeth that presented with IP, half of the intracanal samples had a substantial bacterial load (16S rRNA copies) within the IP vital pulp as determined by quantitative polymerase chain reaction. Next-generation sequencing microbial identification was successful in 7 intracanal samples and yielded 187 bacterial operational taxonomic units within the IP samples. The most abundant genera observed among the vital cases were Veillonella (16%), Streptococcus (13%), Corynebacterium (10%), Cutibacterium (9.3%), and Porphyromonas (5.7%).
The current study highlighted the evidence of vital teeth diagnosed as IP harboring considerable bacterial loads and composed of genera reflective of established endodontic pathology and thus may offer insights into the initial events preceding pulpal necrosis.
先前的研究表明，在出现不可逆性牙髓炎（IP）症状的牙齿中，引发炎症的细菌及其产物主要局限于冠髓组织内。本研究旨在使用分子方法确定出现 IP 临床症状的牙髓中细菌的存在和种类。
从 30 名因 IP 症状和体征而到牙科急诊就诊的成年患者中获取样本。经过仔细的表面消毒后，进入牙髓腔，并使用无菌纸尖从发炎的牙髓组织中采集临床样本。从临床样本中提取基因组 DNA，并使用针对保守的 16S 核糖体 RNA（rRNA）基因的定量聚合酶链反应（qPCR）定量细菌。为了表征微生物组成，扩增 16S rRNA 基因的 V3-V5 高变区，并在 MiSeq 平台（Illumina，圣地亚哥，CA）上进行下一代测序。
在 30 颗出现 IP 的牙齿中，通过 qPCR 确定，半数的根管内样本中存在大量的牙髓活体内细菌负荷（16S rRNA 拷贝数）。7 个根管内样本的下一代测序微生物鉴定成功，在 IP 样本中产生了 187 个细菌操作分类单元。在活髓病例中观察到的最丰富的属为韦荣球菌（16%）、链球菌（13%）、棒状杆菌（10%）、不动杆菌（9.3%）和卟啉单胞菌（5.7%）。
本研究强调了诊断为 IP 的活髓牙齿中存在相当数量的细菌负荷的证据，其组成反映了已确立的牙髓病理学，因此可能为牙髓坏死前的初始事件提供一些见解。
