BACKGROUND Extrinsic black stain (EBS) is characterized by discrete dark dots or lines on the tooth surface. The relationship between EBS and oral microbiota in children remains elusive. The aim of this study was to compare dental plaque microbiome in EBS children with that in EBS-free children in the primary dentition. METHODS The Illumina MiSeq sequencing technique was utilized in the cross-sectional pilot study to investigate the diversity and composition of the supragingival plaque microbiota from 10 EBS-positive and 10 EBS-free children. The results were analysed with nonparametric Mann-Whitney U test, Pearson Chi-Square test, Fisher's Exact test and one-way ANOVA tests. RESULTS We identified 13 different phyla, 22 classes, 33 orders, 54 families, 105 genera, and 227 species from a total of 52,646 high-quality sequences. Between two groups, no statistical differences were observed in the estimators of community richness and diversity at 97% similarity, as well as in the Unweighted Unifrac principal co-ordinates analysis (PCoA). At the species level, higher level of relative abundance of Actinomyces naeslundii and lower level of relative abundance of a species belonging to Candidate_division_TM7 was observed in dental plaque of EBS-positive subjects, compared to dental plaque of EBS-free subjects (P < 0.05). This indicated that some species might be involved in the EBS process. CONCLUSION Changes in dental plaque microbiota is possibly relevant to the process of EBS in the primary dentition.

中文翻译：

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使用Illumina MiSeq测序技术比较原始牙列中外源性黑色污渍的牙菌斑微生物组多样性。

背景技术外在黑斑（EBS）的特征在于牙齿表面上离散的黑点或黑线。EBS与儿童口腔微生物群之间的关系仍然难以捉摸。这项研究的目的是比较EBS儿童与原发性无EBS儿童的牙菌斑微生物组。方法采用Illumina MiSeq测序技术进行横断面研究，以调查10名EBS阳性和10名无EBS儿童的龈上菌斑微生物群的多样性和组成。使用非参数Mann-Whitney U检验，Pearson卡方检验，Fisher精确检验和单向ANOVA检验对结果进行了分析。结果我们从总共52,646个高质量序列中鉴定出13个不同的门，22个类，33个目，54个科，105个属和227个种。两组之间，在社区丰富度和多样性的估计量中，在97％的相似度以及未加权Unifrac主坐标分析（PCoA）中，没有观察到统计学差异。在物种水平上，与无EBS受试者的牙菌斑相比，在EBS阳性受试者的牙菌斑中观察到内生放线菌的相对丰度较高，而属于Candidate_division_TM7的物种的相对丰度较低（P <0.05） 。这表明某些物种可能参与了EBS过程。结论牙菌斑微生物群的变化可能与原发牙列中EBS的过程有关。以及Unweighted Unifrac主坐标分析（PCoA）中。在物种水平上，与无EBS受试者的牙菌斑相比，在EBS阳性受试者的牙菌斑中观察到内生放线菌的相对丰度较高，而属于Candidate_division_TM7的物种的相对丰度较低（P <0.05） 。这表明某些物种可能参与了EBS过程。结论牙菌斑微生物群的变化可能与原发牙列中EBS的过程有关。以及Unweighted Unifrac主坐标分析（PCoA）中。在物种水平上，与无EBS受试者的牙菌斑相比，在EBS阳性受试者的牙菌斑中观察到内生放线菌的相对丰度较高，而属于Candidate_division_TM7的物种的相对丰度较低（P <0.05） 。这表明某些物种可能参与了EBS过程。结论牙菌斑微生物群的变化可能与原发牙列中EBS的过程有关。05）。这表明某些物种可能参与了EBS过程。结论牙菌斑微生物群的变化可能与原发牙列中EBS的过程有关。05）。这表明某些物种可能参与了EBS过程。结论牙菌斑微生物群的变化可能与原发牙列中EBS的过程有关。