OBJECTIVETo evaluate the Nidus vespae's cario-static effect on biofilm model in vitro.

METHODSA four-organism bacterial consortium was grown in a biofilm model on hydroxyapatite (HA) discs in a continuous culture system and exposed to repeated solution pulsing respectively. There were three parallel-connected flow cells in the model, so were the three groups with different solution pulsed in. Negative control group was pulsed with distilled water, positive control group was pulsed with 250 mmol/L sucrose solution as well. While 4.0 g/L Nidus vespae together with 250 mmol/L sucrose solution was pulsed in the experiment group. During the experiment, the pH responses against the pulses were recorded. After the 6 pulses, the biofilm surface structure was observed with a scan electron microscope and the population on the biofilm was enumerated.

RESULTSNidus vespae can significantly inhibit the adherence of Streptococcus mutans to HA discs compared with the control group of 250 mmol/L sucrose pulsed in, and can facilitate the remove of acid products. It is also found that the extra-cellular polysaccharide is reduced with the pulsing of Nidus vespae.

CONCLUSIONNidus vespae in the biofilm model can partially decrease the cariogenic response of sucrose solution pulsed in.