Department of Restorative Dentistry & Endodontology, Dental School, Ghent University, Gent, Belgium.
Laboratory of Pharmaceutical Microbiology, Ghent University, Gent, Belgium.
Int Endod J. 2019 May;52(5):604-628. doi: 10.1111/iej.13050. Epub 2018 Dec 20.
The aim of this review was to present an overview of laboratory root canal biofilm model systems described in the endodontic literature and to critically appraise the various factors that constitute these models. The electronic databases MEDLINE, Web of Science and EMBASE were searched up to and including December 2016 to identify laboratory studies using endodontic biofilm models. The following search terms were used in various combinations: biofilm, root canal, in vitro, endodontic, bacteria, root canal infection model, colony-forming unit. Only English papers from journals with an impact factor were selected. The records were screened by two reviewers, and full-text articles were assessed according to pre-defined criteria. The following data were extracted from the included studies: the microbial composition of the biofilm, the substrate, growth conditions, validation and quantification. Seventy-seven articles met the inclusion criteria. In the majority (86%) of the studies, a monospecies biofilm was cultured. In two studies, a dual-species biofilm was grown; others cultivated a multispecies biofilm, containing at least three species. Enterococcus faecalis was the most frequently used test species (in 79% of all studies, 92% of the monospecies studies). Four studies used an inoculum derived directly from the oral cavity. Human dentine was the most frequently used substratum (88% of the studies). Incubation times differed considerably, ranging from one to seventy days. The most common quantification method (in 87% of the studies) was bacterial culturing, followed by microscopy techniques. The variation in laboratory root canal biofilm model systems is notable. Because of substantial variation in experimental parameters, it is difficult to compare results between studies. This demonstrates the need for a more standardized approach and a validated endodontic biofilm model.
本综述的目的是介绍牙髓生物膜模型系统的研究进展，并对这些模型的各种构成因素进行批判性评估。电子数据库 MEDLINE、Web of Science 和 EMBASE 被检索至 2016 年 12 月，以确定使用牙髓生物膜模型的实验室研究。使用了以下搜索词的各种组合：生物膜、根管、体外、牙髓、细菌、根管感染模型、集落形成单位。仅选择具有影响因子的英文期刊的论文。由两名评审员筛选记录，并根据预先确定的标准评估全文文章。从纳入的研究中提取了以下数据：生物膜的微生物组成、基质、生长条件、验证和量化。77 篇文章符合纳入标准。在大多数（86%）研究中，培养了单种生物膜。有两项研究培养了双种生物膜；其他研究培养了至少包含三种细菌的多种生物膜。粪肠球菌是最常使用的测试物种（在所有研究中占 79%，在单种研究中占 92%）。四项研究使用直接来源于口腔的接种物。人牙本质是最常使用的基质（占所有研究的 88%）。孵育时间差异很大，从一天到七十天不等。最常用的定量方法（在 87%的研究中）是细菌培养，其次是显微镜技术。实验室根管生物膜模型系统的差异显著。由于实验参数存在很大差异，因此很难比较研究之间的结果。这表明需要更标准化的方法和经过验证的牙髓生物膜模型。
