Salivary biochemical indices related to early childhood caries.

OBJECTIVES: This study aimed to compare the salivary biochemical indices between caries-free individuals and those with early childhood caries (ECC), and construct a saliva-based caries diagnostic model by analyzing the correlation between salivary biochemical indices and caries severity. METHODS: A total of 120 children aged 4-6 years were selected and divided into two groups: individuals with ECC (C group, n=60) and healthy children (H group, n=60). Salivary samples were collected to compare the pH, total protein, and ion concentrations between the two groups. The correlation between the salivary biochemical indices and caries severity was examined, and an ECC diagnostic model was established. RESULTS: The NO3- concentration significantly decreased in the C group, whereas the Cl-, Br-, NH4+, and Mg2+ concentrations significantly increased in the C group (P<0.05). In addition, the salivary caries severity had a significantly negative correlation with the NO3- concentration but had a positive correlation with Br-, Cl-, and NH4+ concentrations (P<0.05). The ECC diagnostic model based on salivary biochemical indices could yield satisfactory results in terms of distinguishing the C and H groups with over 85% accuracy. CONCLUSIONS: Salivary biochemical indices can contribute to the diagnosis and risk assessment of ECC.

[Salivary microbial communities associated with severe early childhood caries].

OBJECTIVE: To compare the salivary microbial profiles of healthy subjects and those with severe early childhood caries (S-ECC) by using high-throughput sequencing. METHODS: Salivary samples were obtained from children with S-ECC (group C, n=24) and healthy children (group H, n=24). Total metagenomic DNA was extracted, and DNA amplicons of the V1-V3 hypervariable region of the 16S rRNA gene were generated and subjected to 454 sequencing. The characteristics of oral microbial communities from the two groups were compared based on microbial diversity and taxonomy assignment. RESULTS: First, the microbial richness was significantly higher in group C than group H (P<0.05). Second, the microbial community structure was significantly different for the groups H and C (P<0.01). In addition, caries microbiota was significantly conserved in group C (P<0.001). High expression of suspected cariogenic microorganisms in group C (P<0.1) and health related microorganisms in group H (P<0.1) were identified. Finally, models of caries risk assessment were proposed to distinguish caries from healthy subjects with over 70% accuracy. CONCLUSIONS: Salivary microbiota and certain taxa, such as caries-associated taxa (Prevotella), may be useful to screen/assess the children's risk of developing caries.