[Relationship between Streptococcus mutans, Lactobacillus spp. and lactate-producing level and nursing bottle caries].

OBJECTIVE: The study aimed to investigate the levels of Streptococcus mutans and Lactobacillus spp. as well as the relationship between lactate-productive and aciduric organisms and nursing bottle caries. METHODS: Totally, 30 children of 2- to 2.5-year-old were divided into two groups, including the group of nursing bottle caries and the group of caries-free. Streptococcus mutans and Lactobacillus spp. were isolated from dental plaque of all the children. The amount of lactate produced was measured with a microlitre plate reader. RESULTS: The isolation frequency of Streptococcus mutans and Lactobacillus spp. were both 100 percent in the children with nursing bottle caries, and that the composition of these bacteria from nursing bottle caries lesions was higher than that of caries-free dental surface. Lactate-producing level was higher in the caries group than that of the caries-free group. CONCLUSION: This study suggests Streptococcus mutans and Lactobacillus spp. may be the major pathogenic bacteria leading to nursing bottle caries.