Dental Instruments ; Humans ; Root Canal Preparation

Objective: To analyze the effect of different treating factors on cure depths of light curing composite resin, and discuss the relationship between different treating factors and cure depths. Methods:192 samples were designed with factorial experiment. The whole samples were scanned by Planmeca ProMax panoramic X-ray unit and cure depths were measured. The data was statistically analyzed by SPSS 11.5 software package for t test and stepwise regression analysis. Results:There were significant differences among different light curing units, irradiation distances and cure time(P

Objective　To evaluate the influence of various cavity designs, lining and restorative materials on fracture resistance of teeth in vitro. Methods　Factorial design with three factors and various levels was used.36 extracted human maxillary premalors were prepared for occlusal cavity, MO cavity and MOD cavity. Various base material and restorations were used. All teeth were thermocycled and mounted for testing and then were loaded until fracture. The results were analyzed by a three-way ANOVA. Fracture patterns were observed at the same time. Results　There was significant difference in fracture resistance among various cavity designs and restorations. The fracture patterns were different. Conclusions　The different classes of cavities and various restorations have significantly influence upon fracture resistance of teeth. There are interactions between cavities and restorations.

This study was aimed to observe changes of key molecular in insulin signaling pathway in the hypothala-mus of rats to explore the mechanism of spleen yin deficiency diabetes-associated cognitive decline (DACD) and Zibu Piyin Recipe (ZBPYR) in order to provide new ideas and new clues for treatment of DACD. Rats were randomly divided into five groups, which were the control (Cont) group, diabetes (DM) group, spleen yin deficiency (pi) group, spleen yin deficiency diabetes (piDM) group and the ZBPYR group. Insulin receptor substrate 1 (IRS-1) serine phos-phorylation levels and protein kinase B (PKB/Akt) serine phosphorylation levels which were involved in the insulin signaling were observed by western blotting in the hypothalamus to determine whether there were insulin signaling obstacles in the hypothalamus of rats. The results showed that the expression of p-IRS-1ser in the DM group, pi group and piDM group was increased compared with the Cont group (P< 0.05); while the p-Akt expression of the DM group and piDM group was decreased (P< 0.05). The expression of p-IRS-1ser in the ZBPYR group decreased compared with the DM group and piDM group (P< 0.05); while the level of p-Akt increased compared with the DM group and piDM group (P < 0.05). It was concluded that insulin signaling was not transduced normally in the hy-pothalamus of the DM group, pi group and piDM group. Insulin resistance may occur in the hypothalamus. And ZBPYR can correct insulin signaling transduction disorder.

Objective To clarify the pathogenesis of spleen yin deficiency diabetes-associated cognitive decline (DACD) and mechanism of Zinu Piyin Recipe (ZBPYR) by observing the expression of phosphorylated RNA-dependent protein kinase-like endoplasmic reticulum kinase (PERK), eukaryotic initiation factor 2α subunit (eIF2α), p-eIF2α, glucose-regulated protein 78 (GRP78) in cerebral cortex of spleen yin deficiency diabetes mellitus rats. Methods The rats were randomly divided into control group, diabetes mellitus group, spleen yin deficiency group, spleen yin deficiency diabetes mellitus group (disease-syndrome group) and spleen yin deficiency diabetes mellitus+ZBPYR group (treatment group). Type 2 diabetes mellitus models were established by high-fat food feeding for 4 weeks and low dose STZ intraperitoneal injection. Then the classical compound method was used to construct spleen yin deficiency rats model by improper diet, over exertion and yin fluids exhaustion. The reatment group was given ZBPYR and other groups were given equal volume of normal saline for 15 days, then cerebral cortex was obtained. The expression of p-PERK, p-eIF2α, eIF2α and GRP78 were observed by Western Blot and RT-PCR. Results The protein expression of p-PERK, p-eIF2α, and mRNA expression of GRP78 of diabetes mellitus group, spleen yin deficiency group and disease-syndrome group was enhanced compared with control group (P<0.05). GRP78 protein expression of diabetes mellitus group, disease-syndrome group was increased compared with control group (P<0.05). The protein expression of p-PERK, p-eIF2α, GRP78 and mRNA expression of GRP78 of treatment group was decreased compared with diabetes mellitus group and disease-syndrome group (P<0.05). Conclusion Endoplasmic reticulum stress is involved in spleen yin deficiency DACD. ZBPYR improves learning and memory ability by reducing endoplasmic reticulum stress.