[The relationship between Streptococcus sobrinus and rampant caries in children]

To explore the relations between Streptococcus sobrinus (S. Sobrinus) and rampant caries in children.

Based on previous investigation result for rampant caries in Zhengzhou city, 66 children aged 3-5 years were selected by random sampling, and divided into 3 groups of rampant caries, high dental caries and no caries, 22 cases in each group. The final identification of S. mutans and S. sobrinus were performed after using culture medium TYCSB to operate preliminary screening of Streptococcus mutans (S. Mutans) and S. Sobrinus with polymerase chain reaction(PCR) combined with physiological and biochemical identification. SPSS10.0 software package was used to compare the detection rate and mean values of S.mutans and S.sobrinus in the experimental group and the control group.

It was found that single S. sobrinus without S. mutans was not detected from dental plaque in each group. The detection rate of S. mutans in group of rampant caries was higher than in group of high dental caries, but there was no significant difference (P>0.05). The difference of detection rate of S. sobrinus between the two groups and the detection rate of S. mutans between group of rampant caries and group without caries was significant(P<0.05). The difference of the detection rate of S. sobrinus between group of rampant caries and group without caries was also significant(P<0.01). The incidence of rampant caries, DMFT, DMFS, smooth-surface caries among the sample with both of S. sobrinus and S. mutans detected and the sample only with S. mutans and the sample without S. sobrinus and S. mutans were significantly different (P<0.01).

The main pathogenic bacteria of rampant caries in children are S. mutans and S. sobrinus. The incidence of rampant caries was related to S. sobrinus, which had synergic effect on the occurrence and development of rampant caries in children.