Objectives As a vulnerable group, the elders’ oral health gained less attention, particularly the relationship between socioeconomic status (SES) and dental caries. This study aimed to assess the associations and to explore the effects of confounders on the associations in elderly people. Design Cross-sectional study. Settings 3 neighbourhood committees and 3 village committees in Sichuan Province, China. Participants 744 people (362 men and 382 women) aged 65–74 years were included. Outcome measures Oral health outcomes included the decayed, missing and filled teeth (DMFT) index and its components. SES was assigned by educational level, household income and type of household. The bivariate association between the participants’ characteristics and DMFT was analysed using non-parametric tests. Four logistic regression models were used to analyse the associations between SES and dental caries by regulating confounders. Results Poor oral health was observed in these participants. Bivariate analysis showed a significant association between SES and DMFT (p﹤0.05). Only adjusting gender, high educational level (adjusted (AOR)=0.34, 95% CI 0.17 to 0.66), high household income (AOR=0.47, 95% CI 0.41 to 0.77) were protective factors against dental caries, and living in agricultural families (AOR=1.86, 95% CI 1.32 to 2.63) was risk factor (p﹤0.05). After adjusting other confounders, SES was partly related to the dental caries. Moreover, an interaction existed among SES indicators. Conclusions SES is associated with dental caries, and older people with low SES have poor oral health. The associations were explained partly by diet, behaviour and awareness. Our results provide effective evidence in targeted policy-making and intervention measures and implicate that pertinence measures, economic assistance and medical insurance funds should be provided to older people of low SES. Furthermore, a follow-up design should attempt to confirm the causal relationship between SES and dental caries and evaluate the effect of intervention.

Lipopolysaccharide exerts many effects on many cell lines, including cytokine secretion, and cell apoptosis and necrosis. We investigated the in vitro effects of lipopolysaccharide on apoptosis of cultured human dental pulp cells and the expression of Bcl-2 and Bax. Dental pulp cells showed morphologies typical of apoptosis after exposure to lipopolysaccharide. Flow cytometry showed that the rate of apoptosis of human dental pulp cells increased with increasing lipopolysaccharide concentration. Compared with controls, lipopolysaccharide promoted pulp cell apoptosis (P < 0.05) from 0.1 to 100 μg/mL but not at 0.01 μg/mL. Cell apoptosis was statistically higher after exposure to lipopolysaccharide for 3 days compared with 1 day, but no difference was observed between 3 and 5 days. Immunohistochemistry showed that expression of Bax and Bcl-2 was enhanced by lipopolysaccharide at high concentrations, but no evident expression was observed at low concentrations (0.01 and 0.1 μg/mL) or in the control groups. In conclusion, lipopolysaccharide induced dental pulp cell apoptosis in a dose-dependent manner, but apoptosis did not increase with treatment duration. The expression of the apoptosis regulatory proteins Bax and Bcl-2 was also up-regulated in pulp cells after exposure to a high concentration of lipopolysaccharide.