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The progression of early childhood caries (ECC) is caused by microbial colonized in dental plaque. However, the association framework both from 16s genus down to high resolution metagenomic strain level and from composition to genome function analysis on caries lacks. 16S rRNA sequence revealed the composition of 3-6 years dental caries (ECC, n = 29), and severe dental caries (SECC, n = 36) children are significantly different from caries-free controls (CF, n = 31). Especially, genus Neisseria is enriched in caries (P < 0.05). Metagenomics sequence of 3 ECCs, 3 SECCs, and 3 CFs reveals Neisseria bacilliformis ATCC BAA-1200 in genus Neisseria is also significantly enriched in caries (P < 0.05). Then, we recovered high-quality metagenomic assembly genomes (MAG), named bin 86, which have 99% identity with Neisseria bacilliformis ATCC BAA-1200 genome. Function analysis of Neisseria bacilliformis ATCC BAA-1200 genome shows its metabolism power of sugar and adhesion, colonization, acid production, and acid tolerance ability, which suggested Neisseria bacilliformis ATCC BAA-1200 may serve as a biomarker for childhood caries.
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Objective@#To study the difference in the flora structure and gene function of dental plaque in caries-free and caries-active preschool children by 16S rRNA sequencing.@*Methods@#After oral examination of 96 preschool children aged 3-6 years, they were divided into 3 groups according to their decayed, missing and filled surface (dmfs) index: group CF with no caries (n=31), group ECC with moderate early childhood caries (n=29) and group SECC with severe early childhood caries (n=36). Dental plaques were collected, and DNA was extracted and then underwent metagenomic sequencing by Illumina HiSeq 2 500. The bacterial community structure was analyzed by Qiime. @*Results @#A total of 12 phyla, 31 classes, 31 orders, 50 families, 92 genera and 1 104 species were found in the dental plaque samples of the three groups, most of which belonged to 9 dominant genera, including Streptococcus, Veillonella, etc. The microbial diversity of the dental plaques in the three groups was similar (P > 0.05). Veillonella, Lactobacillus, Megasphaera, and Scardovia in the SECC group were significantly higher than those in the other two groups. There was a significant correlation between the decayed, missing and filled surface (dmfs) index and the genus. Bifidobacterium, Veillonella, Lactobacillus had a positive correlation with the dmfs index, while Eikenella had a negative correlation with the dmfs index. Indicator species analysis showed that Atopobium, Veillonella, Megasphaera, Scardovia, Lactobacillus and Bifidobacterium had high indicative values in the SECC group. @*Conclusion @# There are significant differences in plaque microbiota among preschool children with different caries sensitivities. Veillonella, Megasphaera, Scardovia, Lactobacillus, Bifidobacterium and Atopobium may be the indicator genera of severe early children caries.
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Objective @#To compare the wear of Ceramage and IPS e.max Press offering foundation for nonmetallic materials selection in clinical. @*Methods @#20 class I cavities were prepared in the approximal flattened sides of the extracted human maxillary first molars. The cavities were divided into 2 groups randomly, and then restored with Ceramage or IPS e.max Press. Inlays were prepared according to the manufactures’ instructions with indirect methods and cemented with Varolink N. The non-wear extracted maxillary third molars were used as antagonistic enamel cusps after standardized prepared. After the self-made wear-testing device concluded 200,000 cycles under a load of 20 N, the wear depth of specimens and antagonistic enamel cusps was assessed by Kavo PREP assistant.@*Results @# The wear in Ceramage group was (298.30 ± 40.02) μm, while the wear of normal enamel was (206.60 ± 49.17) μm. The wear in IPS e.max Press group was (212.90 ± 61.21) μm, while the wear of normal enamel was (217.00 ± 25.10) μm. The wear of IPS e.max Press inlays was higher than Ceramage inlays (P < 0.05). Ceramage inlays showed higher wear than normal enamel (P < 0.05), while IPS e.max Press inlays was not statistically different from the normal enamel (P > 0.05). @*Conclusions @#Ceramage has more wear than IPS e.max Press. Ceramage shows higher wear compared with normal enamel, while IPS e.max Press has lower antagonistic war compared with normal enamel.
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OBJECTIVE: To calculate the delay times and embedding dimensions of surface electromyogragh (sEMG) signal of the masseter and temporal muscle during clenching at intercuspal position (ICP), and to reconstruct the space phase of sEMG signal with method of nonlinear dynamics. METHODS: Ten male and 10 female young volunteers with normal masticatory system were included in the study, the signals of surface sEMG of bilateral masseter and temporal muscles in the position of ICP were collected, and the delay times and embedding dimensions of the sEMG signals were calculated using C-C method, the space phase of the sEMG signals was reconstructed. RESULTS: A program of nonlinear dynamic analysis of mastication muscles sEMG signals was developed base on the platform of Matlab. The signals of the sEMG of the masseters and temporals were analyzed with nonlinear dynamic methods, the delay times and embedding dimensions of each muscles sEMG signals were obtained, and the space phase of each sEMG signals were reconstructed. The graphs of the space phase indicated the typical characteristic of chaotic attractor. CONCLUSIONS: The signals of the masseter and temporal muscles of surface sEMG during clenching at ICP of normal masticatory system show the typical characters of chaos, the methods of nonlinear dynamics are effective to analyze the sEMG signals of mastication system.
