sequences of bacteria
12 male specific-pathogen-free Sprague-Dawley rats aged 17 days were purchased from the Animal Experimental Centre of Sichuan University. For the first 3 days, the water was supplemented with chloramphenicol, ampicillin, and carbenicillin [1g/kg], and then the animals were screened for indigenous S. mutans by an oral swab streaked on MSB agar. After rush-out period of 3 days, animals aged 24 days were randomly assigned to two groups: the Core group and the Core+ LGG group. The rats were then infected orally with mixed bacteria suspension for 5 weeks according to the group set. The rats were fed the cariogenic Keyes 2000 diet (Trophic, Nantong, China) and 5% sucrose water  ad libitum 18during the 5-week treatment. The rats weights were recorded to monitor for signs of toxicity. Before, during, and at the end of the treatment, saliva and supragingival biolm were sampled from the supragingival regions of the rats (aged 24d, 31d, 38d, 59d) by oral swabbing.