[The effect of iron deficiency anemia and black stain on the microbial community of dental plaque in young children with early childhood caries].

<b>Objective:</b> To analyze the effect of Iron deficiency anemia (IDA) and Black stain (BS) on the microbial community of dental plaque. <b>Methods:</b> A total of 136 preschool children aged 3 to 6 years old from 12 kindergartens in Shinan District and Shibei District of Qingdao City were investigated by using a cluster sampling method from April to May 2019. They were divided into two groups based on oral examination: the early childhood caries (ECC) group and the caries-free (CF) group. According to whether they had IDA and BS, they were further divided into four groups: the IDA with caries (IDA-ECC) group, the non-IDA with caries (NIDA-ECC) group, the BS without caries (BS-CF) group and the non-BS without caries (NBS-CF) group. The gingival plaque of the study subjects was collected. The 16S rRNA gene was sequenced by using Illumina MiSeq high-throughput sequencing technology. The composition, community structure and different bacteria genera of the microbial communities between the groups were compared and analyzed. Potential biomarkers within each group were further identified by linear discriminant analysis of effect size (LEfSe). <b>Results:</b> The 136 children were aged (5.11±0.87) years old, with 80 boys (58.82%). There were statistically significant differences in the microbial composition, structure and function of oral plaque between the ECC and CF groups (<i>P</i><0.05). There were statistically significant differences in the microbial richness and diversity of oral plaque between the IDA-ECC and NIDA-ECC groups (<i>P</i><0.05). There was no significant difference in microbial diversity index between the BS-CF and NBS-CF groups (<i>P</i>>0.05). The LEfSe analysis results showed that 41, 31 and 9 taxa with different relative abundance were identified between the ECC and CF groups, IDA-ECC and NIDA-ECC groups, and BS-CF and NBS-CF groups, respectively. <b>Conclusion:</b> IDA and BS have an effect on the microecological diversity and microbial community function of oral plaque in young children with early childhood caries.