OBJECTIVEThis study aims to compare the fracture resistance of teeth restored with different post and core systems by cyclic loading test and to predict long-term effects.

METHODSA total of 15 recently extracted mandibular premolars without crowns were endodontically treated. The teeth were randomly divided into three groups with five teeth in each group. Group A, teeth restored with cast metal post and core. Group B, teeth with fiber post and resin core. Group C, teeth with resin filling. All of the teeth were restored with full-cast metal crowns. The specimens were exposed to 300,000 cyclic loadings in a cyclic loading machine and 1,000 thermal cycles between 5 and 55 °C. All of the samples were loaded in AG-IS mechanical testing machine with a compressive load until fracture occurred. The fracture load and the fracture mode of each tooth were recorded.

RESULTSThe fracture resistance in group B and C were higher than that of the cast metal post and core restoration (P < 0.05). Repairable fractures were observed in group B and C, whereas unrestorable and catastrophic fractures were found in group A.

CONCLUSIONFiber post and resin filling is a good choice to restore endodontically treated teeth.

80 extracted human mandible premolars were divided into 10 groups(n =8)based on the post with different tilted angles(0°, buccal 15°and 30°,ligual 15°and 30°).The samples in experiment group were restored with fiber post while in the control group with cast post.Then all the teeth were restored with cast crown and bonded by glass ionomer.Compressive load with the speed of 1.0 mm/min was ap-plied to the restored teeth with a universal material testing machine until failure and the fracture modes were observed.The fracture load of fi-ber post and cast post restoration with the same tilted angles was similar(P >0.05).The main fracture mode of the teeth in all groups was unfavorable tooth fracture.No significant interaction was observed(P =0.217)between the 2 kinds of post and angulation of tilted teeth.

Objective:To investigate the feasibility of improving the corrosion resistance of nickel-chromium alloys by the means of cryogenic treatment. Methods:16 disk samples were divided into 4 groups, including control group(C), cryotreat group(E1),tempering after cryotreat group(E2) and simulative porcelain sintering after cryotreat group(E3). All samples were subjected to electrochemical potentiodynamic polarization after immersed in the artificial saliva ISO/TR 10271:1993(E) pH 6.8 for 24 h at ambient temperature. The metallography of all groups were observed by SEM. Results:①Cryogenic treatment elevated the pitting corrosion potential and dropped the corrosion current of Ni-Cr alloys. Following simulative porcelain sintering,as well as tempering after cryotreat, decreased the corrosion current. But the corrosion potential of Ni-Cr alloys fell after cryotreat and following simulative porcelain sintering. Tempering after cryotreat did not affect the pitting corrosion potential. ②Much small secondary substance separated out and evenly distributed along the crystals of Ni-Cr alloys after cryotreat. Conclusion:Cryogenic treatment effectively improves the electrochemical corrosion resistance of Ni-Cr alloys, and tempering following cryotreat is unnecessary. It is not recommended to sintering porcelain after cryogenic treatment.

To study the effects of high salt intake together with cold stress on rat cardiac renin angiotensin aldosterone system (RAAS) in rats. Male Wistar rats were randomly divided into four groups: control, high salt (8%NaCl), cold stress (5 2℃) and compound group (8%NaCl+cold stress). Blood pressure and body weight were measured once a week. The experiment ran for 8 weeks. Renin activity (RA), angiotensinⅡ (AngⅡ), and aldosterone (Aldo) in plasma and left ventricle were determined with radioimmunoassay. Angiotensin II receptor mRNA was determined with RT PCR. The results showed that ①Rats in compound group had higher blood pressure than rats in the other three groups ( P

Objective To investigate the correlation between carotid artery intima media thickness (IMT) and cerebrovascular hemodynamic analysis (CVA) and the diagnostic value in ischemic stroke.Methods Using colour Doppler IMT,IMT/D ratio and CVA were performed in 120 patients with hyperacute and acute ischemic stroke as compared with the health controls.Results IMT and IMT/D ratio were higher in patients with ischemic stroke than the health aduts. Vmean and Qmean in ischemic stroke hyperacute group were lower, and R,DR were higher obvious in hyperacute group than that of acute group. IMT and IMT/D ratio were negatively correlation with Vmean and Qmean and positively correlation with R and Zc.Conclusion The measurement of carotid artery IMT and CVA have clinical significance in early diagnosis of ischemic stroke.

Objective To compare the effects of different composite resins as core material on the degree of microleakage in post-core repairation.Methods A total of 46 recently extracted single-rooted mandibular premolars were distributed into different groups according to different core material including ParaCore,AP-X and Ceramage.Then we used direct or indirect forming method to make post-core restorations.All of the specimens were submerged in dyes.Then,they were demineralized,dehydrated and processed to be transparent.The extent of the dye leakage was examined under a stereomicroscope.Results The microleakage value was significantly higher in Group of direct-mold-cement with ParaCore (4.94± 1.71)mm than in Group of indirect-mold-secondary-cement with ParaCore (0.91 ± 0.33) mm,Group of indirect-mold-secondary-cement with AP-X (0.87 ± 0.27) mm,and Group of indirect-mold-secondary-cement with Ceramage (1.02 ± 0.34)mm.Conclusion Different methods of building and cementing FRC post-core restorations,but not different composite resins as core material,have significant effects on the extent of microleakage in post-core repair.

To compare the microleakage of fiber post and resin-core system fabricated by different methods.The roots of 36 recently extracted single-rooted mandibular premolars were undergone endodontic treatment.Fiber posts and Paracore flowable resin composite were used for fabricating post-core restorations.Microleakage was examined by dye penetration method.The microleakage value was significantly higher in Direct-Mold-Cement-Method group(4.94 ± 1.71) mm compared to Direct-Mold-Secondary-Cement-Method group(0.91 ±0.33) mm and Indirect-Mold-Secondary-Cement-Method group (0.87 ± 0.27) mm (P ＜ 0.05).

Student as standard patient(SSP) was defined as student receiving relative medical training,who was willing to act as a human analogue as a patient and could be used as not only a patient but also a teacher in clinic practice.The results indicates that the using of SSP in the clinical teaching of endocrinology could promote the students'level in practice and in the meanwhile,it could be useful to testing the learning result.

quamous metaplasia occurred, the expression of occludin and ZO-1 in cells were similar to those in control group, which might play a role in the defense function of neovaginal mucosa.

Objective To observe the clinical efficacy and safety of Chushi Huowei Decoction in treating inflammation of gastric relict of spleen-stomach damp heat type. Methods Totally 62 patients with inflammation of gastric relict were divided into treatment group and control group with random number table, 31 patients in each group. The control group was given hydrotalcite and the treatment group was treated by adding of Chushi Huowei Decoction. After eight-week treatment, the clinical efficacy, gastric mucosal lesions efficacy, and gastric mucosal pathology efficacy of the two groups were compared. Results Eight-weeks later, traditional Chinese medicine symptom scores of both groups were obviously lower than those before treatment (P<0.01). And the decrease in the treatment group was more obvious than that in the control group (P<0.01). Curative effects of gastric mucosal lesions and pathologic condition in treatment group were better than those in the control group (P<0.05, P<0.01). Neither groups had any adverse reaction. Conclusion Chushi Huowei Decoction has reliable therapeutic effect and safety in treating inflammation of gastric relict of spleen-stomach damp heat type.