Objective:To assess the cytotoxicity of self-adhesive resin cement RelyXTM U200 on human periodontal ligament fibro-blasts(HPDLFs)under different light treatment modes.Methods:The self-adhesive resin cement RelyXTM U200 was cured by immediate light(A),intermittent light(B),delayed light(C)and no light(D)treatment respectively.The HPDLFs were cultured with the specimen extracts under different light modes.The proliferation ability and apoptosis level of the cells in the groups were detected by CCK-8 test and flow cytometry apoptosis test.SPSS 20.0 software was used to analyze the cytotoxicity of specimens to HPDLFs.Results:At 24 h after light treatment the cytoxicity(grade)of group A,B,C and D was 1,2,3 and 4,at 72 h 1,2,2 and 3,respectively.At 72 h,the apoptosis index(％)of the cells in A,B,C and D groups was 6.38％±0.94％,16.34％±1.67％,24.13％±1.43％and 38.34％±2.75％respecitvely.Conclusion:The cytotoxicity of self-adhesive resin cement is the greatest under no light treatment mode and the least under immediate light treatment mode.

Objective:To assess the cytotoxicity of self-adhesive resin cement RelyXTM U200 on human periodontal ligament fibro-blasts(HPDLFs)under different light treatment modes.Methods:The self-adhesive resin cement RelyXTM U200 was cured by immediate light(A),intermittent light(B),delayed light(C)and no light(D)treatment respectively.The HPDLFs were cultured with the specimen extracts under different light modes.The proliferation ability and apoptosis level of the cells in the groups were detected by CCK-8 test and flow cytometry apoptosis test.SPSS 20.0 software was used to analyze the cytotoxicity of specimens to HPDLFs.Results:At 24 h after light treatment the cytoxicity(grade)of group A,B,C and D was 1,2,3 and 4,at 72 h 1,2,2 and 3,respectively.At 72 h,the apoptosis index(％)of the cells in A,B,C and D groups was 6.38％±0.94％,16.34％±1.67％,24.13％±1.43％and 38.34％±2.75％respecitvely.Conclusion:The cytotoxicity of self-adhesive resin cement is the greatest under no light treatment mode and the least under immediate light treatment mode.

Maxillary first molar teeth usually have 4 cusps,a few teeth have stuck cusps on the lingual side of the mesial tongue tip,while the presence of additional cusp on the buccal side of the mesial buccal tip is rarely reported,and it is even more rare for the cusp to connect with the dentin,cementum and pulp cavity of the main crown and fuse together to form C-shaped roots.A case of the buccal supernumerary cusp of the right maxillary first molar with C-shaped root canal was reported.

Maxillary first molar teeth usually have 4 cusps,a few teeth have stuck cusps on the lingual side of the mesial tongue tip,while the presence of additional cusp on the buccal side of the mesial buccal tip is rarely reported,and it is even more rare for the cusp to connect with the dentin,cementum and pulp cavity of the main crown and fuse together to form C-shaped roots.A case of the buccal supernumerary cusp of the right maxillary first molar with C-shaped root canal was reported.

Objective To investigate the effect of iRoot BP Plus on the repair of dental pulp cavity during pulp injury in rats,and to explore the possible role of iRoot BP Plus in the process of damage repair.Methods Bilateral maxillary first molars of 60 8-week-old SD rats were treated with direct pulp capping after pulp opening.They were divided into iRoot BP Plus group(BP group)and control group.After histological processing,the damage of dental pulp tissue and the calcification of pulp cavities were observed by microCT and HE staining.mRNA was extracted from rat dental pulp tissue,and the expression of inflammation and mineralization genes were detected by real-time quantitatitive PCR.Results The results of this study showed that the dental pulp tissue had different degrees of calcification at 1,4 and 7 days after direct pulp capping.There was no significant difference between the BP group and the control group on the 1st day after the operation,but on the 4th and 7th day after the operation,a regular calcified bridge was formed at the pulp hole in the BP group,and more pulp tissue was retained in the pulp cavity.In the control group,a large area of irregular calcified tissue was formed below the pulp hole.HE staining results showed that the pulp tissue had a heavy inflammatory response,and a large number of inflammatory cells infiltrated near the pulp orifice on the first day after the operation.On the 4th and 7th days after the opera-tion,mineralized tissue began to form near the pulp orifice in the BP group,and healthier pulp tissue was retained in the pulp cavity.The gene levels of IL-1β and TNF-α in the BP group were lower than those in the control group,and the gene expression levels of min-eralization indexes COL1 and DSPP were higher than those in the control group.The difference was statistically significant(P＜0.05).Conclusion Dental pulp injury can induce the immune defense response.If the inflammation is not well controlled,it will stimulate the calcification of dental pulp cavities.iRoot BP Plus can better regulate the dental pulp microenvironment,control the development of inflammation,reduce the formation of adverse calcified masses in the pulp cavity after pulp injury,and preserve more pulp tissue.

Objective To investigate the effect of iRoot BP Plus on the repair of dental pulp cavity during pulp injury in rats,and to explore the possible role of iRoot BP Plus in the process of damage repair.Methods Bilateral maxillary first molars of 60 8-week-old SD rats were treated with direct pulp capping after pulp opening.They were divided into iRoot BP Plus group(BP group)and control group.After histological processing,the damage of dental pulp tissue and the calcification of pulp cavities were observed by microCT and HE staining.mRNA was extracted from rat dental pulp tissue,and the expression of inflammation and mineralization genes were detected by real-time quantitatitive PCR.Results The results of this study showed that the dental pulp tissue had different degrees of calcification at 1,4 and 7 days after direct pulp capping.There was no significant difference between the BP group and the control group on the 1st day after the operation,but on the 4th and 7th day after the operation,a regular calcified bridge was formed at the pulp hole in the BP group,and more pulp tissue was retained in the pulp cavity.In the control group,a large area of irregular calcified tissue was formed below the pulp hole.HE staining results showed that the pulp tissue had a heavy inflammatory response,and a large number of inflammatory cells infiltrated near the pulp orifice on the first day after the operation.On the 4th and 7th days after the opera-tion,mineralized tissue began to form near the pulp orifice in the BP group,and healthier pulp tissue was retained in the pulp cavity.The gene levels of IL-1β and TNF-α in the BP group were lower than those in the control group,and the gene expression levels of min-eralization indexes COL1 and DSPP were higher than those in the control group.The difference was statistically significant(P＜0.05).Conclusion Dental pulp injury can induce the immune defense response.If the inflammation is not well controlled,it will stimulate the calcification of dental pulp cavities.iRoot BP Plus can better regulate the dental pulp microenvironment,control the development of inflammation,reduce the formation of adverse calcified masses in the pulp cavity after pulp injury,and preserve more pulp tissue.

Objective: To understand associated factors of myopia among middle school students in Zhengzhou and to explore the correlation between myopia with overweight and obesity, to provide a scientific basis for myopia prevention. Methods: A total of 3 297 middle school students from 8 middle schools in Erqi District, Zhongmu County and Xingyang County of Zhengzhou City were selected by a cluster random sampling method to participate in vision testing and questionnaire survey. Chi square test, and Logistic regression analysis were used. Results: Overall prevalence of myopia of middle school students was 80.5%, overweight 14.7%, obesity 10.1% in Zhengzhou. The prevalence of myopia differed significantly by schooling stage, parental myopia status and sex ( χ 2= 18.34, 23.55, 8.98, 26.53, 27.46, 47.25, P <0.05). Significant differences in myopia detection rate by after school homework duration were observed in boys and the entire population( χ 2=12.40, 15.25, P <0.01), and significant differences in myopia detection rate by body mass index (BMI) were only observed in boys ( χ 2=6.32, P <0.05). The distribution of myopia severity was statistically significant by sex among junior school students, and by BMI categories among high school students ( χ 2=22.71, 20.37, P <0.01). Multivariate binary Logistic regression analysis showed that the risk for myopia among school students who were overweight and obese was 1.81 times higher than that of students who were not overweight and obese( P <0.01). Conclusion Overweight and obesity might increase the risk of myopia among middle school students, targeted measures should be taken to maintain the healthy weight of middle school students and reduce the risk of myopia.

Objective To evaluate the application of clinical cases related problem-based-learning (PBL) method in critical care medical standardized resident training program. Methods 84 residents were randomly divided into experimental group (n=42) and control group (n=42) by lottery way. The experimental group received PBL process during clinical case analysis while the control group learned completely through traditional teaching method . The residents' clinical competence were assessed by multiple scale mixed method including question bank examination (QBE), case-based discussion (CBD), direct observation of procedural skills (DOPS), simulation etc, and Likert-type scale questionnaire was used to evaluate the feedback of training residents. SPSS 17.0 was used to do line t test to the data of both groups. Results Finally 84 residents finished the study. There were no difference in the general conditions in two groups. The PBL group achieved higher examination score during QBE [(80.26 ±8.89) vs. (86.10 ±9.32)], CBD [(84.83±5.43) vs. (75.36±6.06)], DOPS [(88.81±6.68) vs. (82.70±6.98)], simulation [(79.86±10.09) vs.(72.71±9.30)]. Except two groups residents all gave high scores in enhancing cross connection in clinical knowledge [(4.786±0.470) vs. (4.571±0.859), P=0.16], and the questionnaire results showed that the resi-dents of PBL group gave higher points in exciting autonomous learning, improving clin-ical analysis ability, accelerating clinical thinking establish, developing independent thinking habits, improving the clinical communication skills and teamwork ability (P<0.05). Conclusion The clinical cases related PBL method can improve the training effects during critical care medical standardized resident training program. It can be used broadly after adapting modification in critical care medical education.

Objective To investigate the effects of ulinastatin on the number of peripheral blood lymphocyte and the percentage of its subsets in patients with severe sepsis. Methods The scores of APECHE II and SOFA, the number of lymphocyte and the percentage of different subsets in these sepsis patients at different treatment time were measured. Results After treatment, the scores of APECHE II and SOFA of severe sepsis patients were decreased, the number of lymphocyte elevated and the percentages of different subset were corrected. Sepsis caused by Gram- positive pathogens had stronger suppression of peripheral blood lymphocyte and subsets compared with Gram - negative pathogens. Conclusion Patients with severe sepsis had less peripheral blood lymphocyte and abnormal subsets. Ulinastatin could help to correct such abnormality.