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Background/purpose: Mutans streptococci, bifidobacteria, and lactobacilli are acidogenic and aciduric bacteria which may be associated with early childhood caries (ECC). This study aimed to analyze the bacterial composition of four cariogenic microorganisms, namely Streptococcus mutans, Streptococcus sobrinus, Bifidobacterium spp., and Lactobacillus spp. in the saliva of Chinese preschool children and to assess the association of the bacterial burden with the caries status. Materials and methods: A total of 109 saliva samples were collected from 36 children with ECC and 73 caries-free (CF) children aged 2-4 years. A questionnaire was used to evaluate other caries risk factors such as dietary habits and oral hygiene practice. A quantitative real-time polymerase chain reaction was performed to determine the presence and loads of the four microorganisms. Pearson's correlation test was conducted to evaluate the relationship between the World Health Organization caries diagnostic criteria dmft/dmfs index scores and saliva levels of the selected bacteria. Results: The prevalence of S. mutans and S. sobrinus in children with ECC was 88.9% and 19.4%, respectively, whereas the prevalence in CF children was 76.7% and 4.1%, respectively. The saliva levels of S. mutans and S. sobrinus in children with ECC were significantly higher than in CF children (P = 0.004 and P = 0.007, respectively) and positively correlated with dmft/dmfs index scores (r = 0.321/0.316 and r = 0.271/0.245, respectively). An association was found between children with caries-active lesions and the frequency of sugar consumption (P = 0.004). No significant difference in the presence and load of Bifidobacterium spp. or Lactobacillus spp. were found between the two groups. Conclusion: S. mutans, S. sobrinus, and sugar consumption appear to be associated with caries status in the studied population, which might be useful for caries screening in Chinese preschool children. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the optimal silver nitrate concentration and tooth immersion period for assessing marginal leakage at the sealant-enamel interface, using micro-CT. Methods: Two experiments were conducted, using eight teeth sealed with a resin composite without etching, in dried but not desiccated, pits and fissures. Five teeth were immersed in 50% silver nitrate for 0, 1, 2, 3, and 4 hours and scanned, using micro-CT, and two evaluators using a newly developed index assessed marginal leakage at the sealant-enamel interface (Experiment A). Experiment B was carried out in the same way as Experiment A, with the difference that teeth were immersed in 50% and 60% silver nitrate for 2 and 3 hours. Reliability of scores was estimated, using weighted kappa coefficient. ANOVA and t-test were applied to test for period and concentration effects. Results: Reliability of collected data was substantial. A statistically significant difference was observed between 50% silver nitrate penetration scores at 0-1 and 2-4 hours of immersion (P< 0.0001) but not between 50% silver nitrate penetration scores at 2-, 3-, and 4-hours of immersion (P> 0.05) (experiment A). Analysis in experiment B showed a period effect (P= 0.03) but no concentration (P= 0.07) and interaction effect (P= 0.64). Combining all data from 50% silver nitrate immersion, analysis showed no statistically significant difference in penetration scores between 2, 3 and 4 hours of immersion (P= 0.33). The newly developed index showed substantial reliability. [ABSTRACT FROM AUTHOR]

The aim of this article is to describe the innovations in the School of Stomatology at Wuhan University (WHUSS) that are likely to shape the future of dental education in the People's Republic of China. There are forty dental schools in China; the five most well known are located in Beijing, Chengdu, Shanghai, Xi'an, and Wuhan. Although patient-centered, comprehensive care has been recommended as the future of dental education, traditional dental education in China still faces many challenges to accomplish this goal. WHUSS, one of the more progressive dental schools in China, has implemented several educational innovations to traditional dental education by restructuring the curriculum through the introduction of problem-based learning (PBL) and other strategies in clinical training. Although implementation of educational innovations is still at an early stage throughout China, it is reasonable to speculate that many schools will develop similar strategies as those developed at Wuhan to improve dental education during the next several years. However, additional research is necessary to evaluate the efficacy of such educational strategies and to determine the appropriate implementation of a contemporary dental curriculum and pedagogic methodology. The curriculum modifications that have been achieved to date as well as the existing challenges are discussed to provide the reader with an understanding of contemporary dental education in China. [ABSTRACT FROM AUTHOR]