Prevalence of Streptococcus mutans and Lactobacillus fermentum and their association with caries and dietary habits in preschool Thai children

Abstract

Aims: To detect the prevalence of Streptococcus mutans and Lactobacillus fermentum in plaque obtained from severe early childhood caries (S-ECC) and caries-free (CF) groups and to assess any association between their prevalence, feeding habits and oral hygiene practices within each group. Study design: Sixty-four supra-gingival plaque samples were collected from S-ECC and CF groups (CF = 30, S-ECC = 34). All participants were asked about feeding habits and oral hygiene care behaviour by direct questionnaire. Methods: After DNA extraction, S. mutans and L. fermentum were amplified using standard PCR. Nested PCR was performed as a second identification method for S. mutans. Results: Mean age in CF and S-ECC was 2. 29 ± 0. 42 and 2. 49 ± 0. 41 years, respectively. Mean dmft in S-ECC was 4. 51 ± 0. 72. By standard PCR, no S. mutans was detected in CF group, while 10 % was detected in S-ECC group. By nested PCR, S. mutans was detected for 48 and 50 % in CF and S-ECC, respectively. L. fermentum was detected for 16 and 40 % in CF and S-ECC, respectively. Conclusion: Nested PCR gave a higher detection frequency than standard PCR but not significant (p ≤ 0. 05). The prevalence of S. mutans was not different between the two groups, while the prevalence of L. fermentum was significantly associated with S-ECC (p ≤ 0. 05). © 2013 European Academy of Paediatric Dentistry.