[Correlations of salivary ion concentration, Streptococcus and Bifidobacterium in children with caries]

To analyze the correlation between the changes in salivary ion concentration, Streptococcus and Bifidobacterium in children with dental caries and the severity of the disease.

Eighty children with dental caries treated from May 2022 to April 2023 were selected as the experimental group. According to the DMFT, they were divided into mild group (DMFT≤15%, n=35) and severe group (DMFT>15%, n=45). Another 80 children without dental caries were selected as the control group. The calcium ion concentration in saliva was detected by methanol-permeabilized calciometric method, the level of Streptococcus and Bifidobacterium was detected by real-time single-quantity PCR technology, and the correlation between DMFT and salivary calcium ion concentration, Streptococcus and Bifidobacterium was analyzed by Pearson correlation analysis. The diagnostic value of salivary calcium ion concentration, Streptococcus and Bifidobacterium for the severity of dental caries in children was evaluated by the receiver operating characteristic curve(ROC), and the area under the curve(AUC) was calculated. SPSS 22.0 software package was used for statistical analysis.

The level of salivary calcium ion concentration, Streptococcus mutans, Streptococcus sobrinus and Bifidobacterium in the experimental group was significantly higher than that in the control group(P＜0.05), and significantly higher in the severe group than in the mild group(P＜0.05). DMFT was significantly positively correlated with salivary calcium ion concentration, Streptococcus and Bifidobacterium (P＜0.05). Based on DMFT, ROC curve was prepared, and AUCs of salivary calcium ion concentration, Streptococcus mutans, Streptococcus sobrinus and Bifidobacterium for assessing the severity of dental caries in children were 0.760, 0.658, 0.718 and 0.705, respectively.

Increased salivary ion concentration, Streptococcus sobrinus, Streptococcus mutans and Bifidobacterium levels are related to dental caries in children, and are positively correlated with the severity of the disease, which has a certain value for assessing the severity of the disease.