Salivary levels of five microorganisms of root caries in nursing home elderly: a preliminary investigation.

BACKGROUND: Streptococcus, Bifidobacteria, Lactobacillus and Actinomyces are acidogenic aciduria that may be associated with root caries (RC). The aim of the study was to analyze Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Bifidobacterium spp., Lactobacillus spp. and Actinomyces naeslundii (A. naeslundii) in the saliva of nursing home elderly, to assess the correlation between bacterial composition and RC for five putative catiogenic organisms. METHODS: In this study, we collected 43 saliva samples and divided into two groups: the root caries group (RCG, n = 21) and the caries-free group (CFG, n = 22). Bacterial DNA was extracted from the saliva samples. The presence and abundance of the five microorganisms were detected by Quantitative real-time PCR (qPCR). Spearman correlation test was performed to evaluate the relationship between the numbers of root decayed filled surfaces (RDFS) and root caries index (RCI) and salivary levels of the bacteria. RESULTS: The salivary levels of S. mutans, S. sobrinus, Bifidobacterium spp. and Lactobacillus spp. were significantly higher in RCG than in CFG (p < 0.05). RDFS and RCI (RDFS/RCI) were positively associated with salivary levels of S. mutans, S. sobrinus and Bifidobacterium spp. (r = 0.658/0.635, r = 0.465/0.420 and r = 0.407/0.406, respectively). No significant differences in presence and amounts of A. naeslundii was observed between the two groups (p > 0.05). CONCLUSION: S. mutans, S. sobrinus and Bifidobacterium spp. in saliva appear to be associated with RC in the elderly. Taken together, the findings indicate that specific salivary bacteria may be involved in the progression of RC.

Greater inequalities in dental caries treatment than in caries experience: a concentration index decomposition approach.

BACKGROUND: The aim of the current study was to (a) measure the socioeconomic inequalities in oral health and examine whether the inequalities are greater in disease experience or in its treatment and to (b) decompose the factors that influence oral health inequalities among the adults of Guangdong Province. METHODS: A cross-sectional study was conducted among 35- to 44-year-old and 65- to 74-year-old adults in Guangdong Province. All participants underwent oral health examinations and answered questionnaires about their oral health. We measured the concentration indices of the DMFT and its separate components, namely, decayed teeth (DT), missing teeth (MT), and filled teeth (FT), to explore the inequalities in oral health status; then, we analysed its decomposition to interpret the factors that influence the inequalities. RESULTS: The results showed that significant inequality was concentrated on FT (CI = 0.24, 95% CI = 0.14/0.33, SE = 0.05). The concentration indices for the DMFT (CI = 0.02, 95% CI = 0.02/0.06, SE = 0.02) and MT (CI = 0.02, 95% CI 0.03/0.08, SE = 0.03) were small and close to zero, while the concentration for DT (CI = - 0.04, 95% CI = - 0.01/0.02, SE = 0.03) was not statistically significant. The results from the decomposition analysis suggested that a substantial proportion of the inequality was explained by household income, high education level, regular oral examination and type of insurance (5.1%, 12.4%, 43.2%, - 39.6% (Urban Employee Basic Medical Insurance System) and 34.5% (New-Type Rural Medical Collaboration System), respectively). CONCLUSIONS: The results indicated greater inequalities in dental caries than in caries experience. Among the included factors, household income, high education level, and regular oral health examinations had the greatest impact on the inequalities in the number of FT. In addition, the current medical insurance systems, including the Urban Employee Basic Medical Insurance System, Urban Resident Basic Medical Insurance System, and the New-Type Rural Medical Collaboration System, have not been effectively used in oral treatment. Policy-making and the implementation of interventions for tackling socioeconomic oral health inequalities should focus on reducing the burden of treatment and providing greater access to dental care for low-income groups. Welfare policies are skewed towards rural areas and low-income people.

Role of connexin 43 in odontoblastic differentiation and structural maintenance in pulp damage repair.

Dental pulp can initiate its damage repair after an injury of the pulp-dentin complex by rearrangement of odontoblasts and formation of newly differentiated odontoblast-like cells. Connexin 43 (Cx43) is one of the gap junction proteins that participates in multiple tissue repair processes. However, the role of Cx43 in the repair of the dental pulp remains unclear. This study aimed to determine the function of Cx43 in the odontoblast arrangement patterns and odontoblastic differentiation. Human teeth for in vitro experiments were acquired, and a pulp injury model in Sprague-Dawley rats was used for in vivo analysis. The odontoblast arrangement pattern and the expression of Cx43 and dentin sialophosphoprotein (DSPP) were assessed. To investigate the function of Cx43 in odontoblastic differentiation, we overexpressed or inhibited Cx43. The results indicated that polarized odontoblasts were arranged along the pulp-dentin interface and had high levels of Cx43 expression in the healthy teeth; however, the odontoblast arrangement pattern was slightly changed concomitant to an increase in the Cx43 expression in the carious teeth. Regularly arranged odontoblast-like cells had high levels of the Cx43 expression during the formation of mature dentin, but the odontoblast-like cells were not regularly arranged beneath immature osteodentin in the pulp injury models. Subsequent in vitro experiments demonstrated that Cx43 is upregulated during odontoblastic differentiation of the dental pulp cells, and inhibition or overexpression of Cx43 influence the odontoblastic differentiation. Thus, Cx43 may be involved in the maintenance of odontoblast arrangement patterns, and influence the pulp repair outcomes by the regulation of odontoblastic differentiation.

Structural equation modelling for associated factors with dental caries among 3-5-year-old children: a cross-sectional study.

BACKGROUND: The aim of the current study was to explore the factors influencing dental caries among 3-5-year-old children in Sichuan Province and the interrelationship between these factors using structural equation modelling (SEM). METHODS: A cross-sectional study was conducted among 2746 3-5-year-old children in Sichuan Province. Examination of caries was conducted on all children and a questionnaire was answered by the children's caregiver. SEM alternative models were constructed to interpret the intricate relationships between socio-economic status (SES), caregiver's oral health knowledge, attitudes, children's oral health behaviours and children's dental caries. RESULT: The results showed that dental caries were significantly associated with dietary behaviours (ß = 0.11, SE = 0.03, P = 0.001, BC 95% CI =0.05/0.18) and SES (ß = - 0.17, SE = 0.03, P<0.001, BC 95% CI = -0.23/- 0.10) directly, While the indirect effect of SES on dmft is in an opposite direction (ß = 0.08, SE = 0.02, BC 95% CI = 0.04/0.12). CONCLUSION: We found that unhealthy dietary behaviours increased the prevalence of dental caries. However, oral health knowledge and attitude failed to affect dietary behaviour in this model. This result warns that oral health education should strengthen feeding-related knowledge. Meanwhile, it also reminds that it is easier known than done. Future oral health education should focus on exploring a more effective way for the public to turn knowledge into action.