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 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.

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 explore the neutrophil to lymphocyte ratio (NLR) and its relationship with the effect of chemotherapy and prognosis in patients with diffuse large B-cell lymphoma (DLBCL).Methods The clinicopathological characteristics and outcome of 51 patients with DLBCL diagnosed by pathological biopsy and immunohistochemistry who received CHOP or R-CHOP regimen were collected and reviewed.According to the median of NLR,the patients were divided into low NLR group (NLR≤2.32) and high NLR group (NLR＞2.32).The prognostic influence of the NLR on overall survival (OS) was studied by Kaplan-Meier method and Log-rank test.To evaluate the independent prognostic relevance of NLR,univariate and multivariate Cox regression models were applied.Results The complete response (CR) rates of the low and high NLR groups were 71.4 ％ (20/28) and 39.1％ (9/23),respectively (P =0.02).The OS in the low NLR group was significantly better than that in the high NLR group (1,2 and 3-year OSs were 96.4 ％,90.4 ％ and 72.3 ％ vs 63.9 ％,52.7 ％ and 42.2 ％,respectively,P =0.009).Univariate and multivariate Cox regression models analysis showed that NLR ＞ 2.32 was an independent prognostic factor (P =0.016).Conclusion An elevated NLR before treatment indicates the poor effect of chemotherapy and prognosis of patients.NLR is an independent prognostic factor for DLBCL.

Objective To explore the effect of multiple positioning procedure for prolapse and hemorrhoids (PPH) in treatment of connective tissue type mixed hemorrhoids,and compare the results between PPH and Milligan-Morgan surgery.Methods One hundred and sixteen patients with connective tissue type mixed hemorrhoids were divided into treatment group (62 cases) and control group (54 cases)according to random digits table method.The patients in treatment group received multiple positioning PPH,and the patients in control group received Milligan-Morgan surgery.The operative time,intraoperative blood loss,postoperative pain score,anal margin edema,wound healing time,perianal scar,anorectal stenosis,anal discharge and anorectal resting pressure were evaluated and compared between 2 groups.Results The operative time and intraoperative blood loss in treatment group were significantly lower than those in control group:(15.0 ± 2.3) min vs.(35.0 ± 3.4) min and (5.0 ± 2.1) ml vs.(15.0 ± 3.2) ml,and there were statistical differences (P ＜ 0.05).The postoperative pain score and wound healing time in treatment group were significantly lower than those in control group:(4.83 ± 0.62) scores vs.(7.82 ± 0.37) scores and (8.2 ± 2.6) d vs.(17.4 ± 3.8) d,the rates of anal margin edema,perianal scar and anorectal stenosis in treatment group were significantly lower than those in control group:8.1％ (5/62) vs.37.0％ (20/54),0 vs.29.6％ (16/54) and 1.6％(1/62) vs.16.7％ (9/54),and there were statistical differences (P ＜ 0.05 or ＜ 0.01).The postoperative anorectal resting pressure was significantly lower than preoperative in control group:(13.80 ± 4.20) kPa vs.(17.20 ± 5.87) kPa,and there was statistical difference (P＜ 0.05).One patient (1.6％,1/62) in treatment group occurred anal discharge,and 10 patients (18.5％,10/54) occurred anal discharge in control group.The rate of anal discharge in treatment group was significantly lower than that in control group,and there was statistical difference (P ＜ 0.01).Conclusions Multiple positioning PPH is effective for the treatment of connective tissue type mixed hemorrhoids.It improves the controllability of the amount of removal and the excision site.It decreases the incidence of anal margin edema,perianal scar and anal discharge scar,which provides an effective protection for the anal function.

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.

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).