Objective: To compare the quantities of water-soluble, water-insoluble glucans synthesized by S. mutans in 3-4 years old children with high dmft and no caries. Methods: The quantities of water-soluble and water-insoluble glucans synthesized by S. mutans from dental plaques of children with high dmft (dmft≥5) and caries-free (dmft=0) were measured using the anthrone method. Results: S. mutans isolated from the children with high dmft had stronger ability in producing both water-soluble and water-insoluble glucans than those isolated from the caries-free children (0.0332 mg/ml v.s. 0.0192 mg/ml and 0.0357 mg/ml v.s. 0.0215 mg/ml respectively). Children with high dmft harbored more isolates with higher water-soluble or water-insoluble glucans producing ability than caries-free children. Water-insoluble glucans produced by all the clinical isolates is higher than water-soluble glucans (0.0301 mg/ml v.s. 0.0267 mg/ml) and the difference was statistically significant. Conclusion: There may be a correlation between the extracellular glucans producing ability of S. mutans and the caries susceptibility in deciduous teeth.

0.05) but the recovery rate of MFP2- by IC and by FSE was statistically different (1.00 v.s. 1.08; P

Objective:To study the psychosocial effect of fluorosis on students with dental fluorosis.Methods:115 students with different types of fluorosis were sampled randomly from fluorosis epidemic area of Xingtai city in Hebei province, including 60 of 12-year-old and 55 of 15-year-old students. Dental fluorosis was classified by Dean's Index (DI). Parents and teachers of the selected students were involved in a psychosocial questionnaire investigation which included five five-point questions, respectively.Results:Prevalence of fluorosis was 89.6% in the young students in the area. Evaluation scores by parents, which included “health of teeth”, “satisfaction of teeth” and “perceived well-being”, decreased with the decline of DI. Statistical difference was found in the answer to the five questions by parents when comparing the evaluation scores of control(without dental fluorosis) group,moderate dental fluorosis group and severe dental fluorosis group(P0.05). Difference of the evaluation scores of parents and teachers on boys and girls was not significant.Conclusion:Fluorosis has psychosocial impact on students, especially evaluated by parents.

Objective:To understand the oral health status of urban and rural residents in China,the Fourth National Oral Health Epidemiological Survey (FNOHES) was conducted in 2015.Materials and methods:Based on the principles of multi-stage,stratified,equal capacity,and random sampling,the subjects included five groups of residents aged 3-5,12-15,35-44,55-64,and 65-74 years in all 31 provinces,municipalities,and autonomous regions except Hong Kong,Macao,and Taiwan.The total sample size was 172,425.The survey covered two areas,namely oral health status and knowledge,attitude and oral health behavior.Results:Residents in China had serious caries and poor periodontal condition.The prevalence of caries was above 50％ in all age groups,subjects without periodontal disease accounted for ＜50％,and fewer than 50％ of subjects brushed their teeth twice a day.Based on the results of the FNOHES,the following suggestions were proposed for improving the oral health in China in the future:to establish and improve the comprehensive prevention and control system for oral diseases,implement a comprehensive prevention and control strategy for priority groups,strengthen the oral health education for all people to improve oral health literacy,enhance dynamic monitoring to scientifically evaluate oral health status,and coordinate multi-party resources to establish and improve the oral health service security system.Conclusion:The oral health status of Chinese residents and their oral health behavior habits need to be improved.With the support of the administrative departments of the government and unremitting efforts of the oral health staff,all sectors of society must be coordinated to strengthen oral health education for the whole population.Furthermore,comprehensive prevention and control measures must be implemented for priority groups.

Objective:To study the effect of thioredoxin domain containing protein 5 (TXNDC5)-peroxiredoxin 2 (Prx2) on the drug resistance of prostate cancer cells.Methods:Prostate cancer PC3 cells were cultured in vitro, treated with the chemotherapy drug cyclophosphamide (5, 10, 15 μmol/L) for 24 hours, and PC3 cells without any treatment was served as the control group. The expression levels of TXNDC5 in PC3 cells were detected by real-time fluorescent quantitative PCR (RT-qPCR) and Western blotting. PC3 cells with TXNDC5 knocking down were exposed by cyclophosphamide and CCK-8 was used to detect the cell viability of siTXNDC5 group and siNC group. The content of reactive oxygen free radicals was determined by reactive oxygen detection kit. PC3 cells and its parental cyclophosphamide-resistant ones with TXNDC5 knocking down were treated by 10 μmol/L cyclophosphamide and subjected for CCK8 assay. The expression of Prx2 in PC3 cells was detected by Western blotting after TXNDC5 was silenced. Prx2 expression was silenced in PC3 cells overexpressing TXNDC5, and cell viability and reactive oxygen free radical content were detected in Vec-Ctrl group, pcTXNDC5 group, siNC group, siPrx2 group and pcTXNDC5+ siPrx2 group. Results:Compared with the control group, cyclophosphamide treatment significantly increased the expression of TXNDC5 at mRNA and protein levels in PC3 cells. After PC3 cells were treated with cyclophosphamide (10, 15 μmol/L) for 12 h, compared with the siNC group, the cell viability in the siTXNDC5 group was significantly suppressed (0.44±0.08 vs. 0.74±0.10, t=3.647, P=0.031; 0.30±0.04 vs. 0.53±0.06, t=6.115, P=0.006). When PC3 cells were treated with 10 μmol/L cyclophosphamide for 6 and 12 h, compared with the siNC group, the production of reactive oxygen free radicals in the siTXNDC5 group was significantly increased (2.68±0.19 vs. 1.58±0.26, t=-6.027, P=0.005; 4.56±0.37 vs. 2.73±0.26, t=-6.995, P=0.003). When PC3 cells and its cyclophosphamide-resistant ones were treated with 10 μmol/L cyclophosphamide for 12 h, compared with the siNC group, the cell viability was significantly inhibited in the siTXNDC5 group. Western blotting analysis showed that the expression of Prx2 was significantly reduced when TXNDC5 was silenced. Silencing Prx2 could significantly attenuate the increase of cell viability and the decrease of reactive oxygen content resulting from TXNDC5 overexpression. PC3 cells were treated with 10 μmol/L cyclophosphamide for 12 h, and the cell viabilities of the Vec-Ctrl group, pcTXNDC5 group, siNC group, siPrx2 group and pcTXNDC5+ siPrx2 group were 0.52±0.07, 0.69±0.03, 0.56±0.05, 0.43±0.05, 0.58±0.07, respectively, and there was a statistically significant difference ( F=8.868, P=0.003). Furthermore, the cell viability in the pcTXNDC5+ siPrx2 group decreased significantly when compared to that of the pcTXNDC5 group ( P=0.045). The contents of reactive oxygen free radicals in the above 5 groups were 3.26±0.46, 2.09±0.49, 3.16±0.38, 4.62±0.26, 2.87±0.36, respectively, and there was a statistically significant difference ( F=16.037, P<0.001). The content of reactive oxygen radicals in the pcTXNDC5+ siPrx2 group was higher than that of the pcTXNDC5 group ( P=0.036). Conclusion:TXNDC5 can reduce the level of reactive oxygen free radicals in prostate cancer cells by regulating the expression of Prx2, so as to promote the drug resistance of prostate cancer cells.