Abstract:
Objective To investigate the effect of Lactococcus lactis (L.lactis) on fissure caries.
Method Twenty SD rats of 21-day-old were randomly divided into 4 groups by the random number table, and 5 rats in each group: Control group (no caries) , L.lactis (Ll) (inoculating L.lactis) , Streptococcus sanguis + Streptococcus mutans + Actinomyces naeslundii (SSA group) (inoculating Streptococcus sanguis, Streptococcus mutans and Actinomyces naeslundii) and Streptococcus sanguis + L.lactis + Streptococcus mutans + Actinomyces naeslundii (SLSA group) (inoculating Streptococcus sanguis, L.lactis, Streptococcus mutans and Actinomyces naeslundii) . All SD rats were fed with cariogenic forage 2000# mixed with the above four group of bacteria. After 6 weeks, the fissure caries and their severity (E, Enamel caries; Ds, slight dentinal caries; Dm, moderate dentinal caries; Dx, extensive dentinal caries) were checked according to Keyes′ system, and further evaluate the effects of L.lactis on dental caries development in SD rats. Each group has 60 teeth. The weight of the rats was measured everyweek. The data were analyzed by One-Way ANOVA and LSD-t test.
Results The mean value of E, Ds and Dm levels of control group were 45.20 ± 3.35, 41.40 ± 2.41 and 14.80 ± 4.32, and the mean value of E, Ds and Dm levels of Ll was 37.60 ± 6.27, 30.00 ± 7.62 and 3.80 ± 4.38. The control group was significantly higher than Ll group (E: t= 2.739, P= 0.010; Ds: t= 4.108, P<0.001; Dm: t= 3.964, P<0.001) . At E, Ds and Dm levels, the mean value of SSA group [ (46.60 ± 1.62) , (44.80 ± 2.14) , (12.80 ± 2.79) ] was higher than SLSA group [ (38.60 ± 5.50) , (31.40 ± 5.27) , (5.20 ± 2.17) ] (E: t = 4.944, P<0.001; Ds: t = 6.606, P<0.001; Dm: t = 3.747, P = 0.001) . The gaining weight (g) of control and Ll group were (156 ± 14) and (161 ± 25) separately, and both did not show statistical difference (t= 0.410, P= 0.687) . The gaining weight (g) of SSA and SLSA were (158 ± 24) and (152 ± 25) separately, and both did not show statistical difference (t= 0.410, P= 0.687) .
Conclusion L.lactis mayprevent the development of dental caries in SD rats.
Key words:
Probiotics,
Lactococcus lactis,
Dental caries,
SD rats
Yanqing Zhang, Zhongchun Tong, Xin Li, Xi Wei. The inhibitory effects of Lactococcus lactis on caries development in rats[J]. Chinese Journal of Stomatological Research(Electronic Edition), 2016, 10(06): 383-388.