OBJECTIVETo evaluate the influence of eugenol-containing and resin-containing endodontic sealers on the bond strength of fiber posts using different strategies of root canal irrigation.

METHODSForty-eight mandibular premolars were endodontically treated. The specimens were randomly assigned into two groups according to different endodontic sealers. Group A used Endofil (eugenol-containing endodontic sealer), and group B used AH-plus (resin-containing endodontic sealer). After post space preparation, each group was randomly assigned into three subgroups according to the strategies of root canal irrigation (eight premolars in each subgroup). Group Al and B1: 0.9%NaCl irrigation; Group A2 and B2: 17% ethylene diamine tetraacetic acid (EDTA)+5.25%NaClO+0.9%NaCl irrigation; Group A3 and B3: ultrasonic agitation associated with 1 7%EDTA+5.25%NaClO+0.9%NaCl. One week after the cementation of fiber posts using RelyX™ Unicem, a push-out test was performed to measure the bond strength of the posts. The microstructure of the root canal surface was examined under scanning electron microscope (SEM).

RESULTSThe bond strengths of the six groups were as follows: Al (7.96±2.23) MPa, A2 (9.95±2.89) MPa, A3 (18.88±3.69) MPa, B1 (11.41±3.71) MPa, B2 (14.00±4.04) MPa, and B3 (19.14±3.27) MPa. Statistical analysis revealed a significant interaction between the different endodontic sealers and the strategies of root canal irrigation (P<0.05). Lower bond strength was found in group Al but not in group BI (P<0.05), and the same result was revealed when comparing group A2 and B2. No significant difference was observed between group A3 and B3 (P>0.05). SEM showed that the root canal in group A3 and B3 achieved the cleanest surface with nearly all dentine tubules opened.

CONCLUSIONThe eugenol-containing endodontic sealer can impair the bond strength of fiber posts compared with the resin-containing sealer when the root canal is irrigated by 0.9% NaCl or 17%EDTA+5.25%NaClO+0.9%NaC. No difference was observed between the two sealers when using 17%EDTA+5.25% NaCIO+0.9%NaCl combined with ultrasonic irrigation.

Bicuspid ; Cementation ; Dental Bonding ; Dental Pulp Cavity ; Dental Stress Analysis ; Dentin ; Humans ; Post and Core Technique ; Root Canal Filling Materials ; Root Canal Irrigants ; Root Canal Therapy

Objective To explore the level of knowledge,attitude and practice in preventing sudden deafness and the influencing factors among nursing students in Taiyuan City.Methods By random cluster sampling,1 187 nursing students from 6 universities in Taiyuan City were surveyed about the level of knowledge,attitude and practice and the influencing factors by questionnaires in November 2013.The results underwent analysis.Results Total scoring rate of knowledge,attitude and practice of preventing sudden deafness in the nursing students was 48.36％ (574/1 187),among which knowledge,attitude and practice was 28.30％ (336/1 187),62.68％ (744/1 187) and 54.34％ (645/1 187),respectively.Logistic regression analysis showed that whether taking health education or not,different parents' education degree and household capita monthly income had significantly different influence on level of knowledge,attitude and practice of preventing sudden deafness,P＜0.01.Significant correlation existed between knowledge and attitude,attitude and practice,r=0.467,0.149,P＜0.05.Conclusions The level of knowledge,attitude and practice of preventing sudden deafness of the nursing students is low and has muhifaceted influencing factors.Colleges and universities should strengthen the health propaganda,and community should step up intervention to the families of low income and low education degree,at the same time to improve the compliance of health behavior in order to play a role in prevention and treatment of sudden deafness among nursing students.

OBJECTIVEThis study investigated the influence of different designs and porcelain/glaze firing on the marginal and internal fit of three kinds of computer aided design/computer aided manufacturing (CAD/CAM) zirconia ceramic implant-supported crowns.

METHODSThree groups of zirconia ceramic implant-supported crowns with different designs were produced from copings by using a Cercon CAD/CAM system (n = 8). The first two groups comprised double-layer crowns (zirconia coping + veneer) with regular (Group A) and full circumferential zirconia-collar marginal designs (Group B). The third group was composed of anatomic single-layer zirconia crowns without cores (Group C). Initially, the marginal and internal gaps of the copings and crowns were individually replicated by light-body silicon and then measured by micro-computed tomography scanning before and after porcelain/glaze firing. Five measurements were employed: vertical marginal gap (MG); horizontal marginal discrepancy (HMD); chamfer area (CA); axial wall (AW); and axial-occlusal transition area (AOT). Statistical analyses were performed by SPSS 17.0.

RESULTSHMD measurements in Group A were statistically higher than those in Groups B and C (P < 0.05), regardless of whether the values were obtained before or after porcelain/glaze firing. By contrast, the HIMD measurements in Groups B and C showed no significant difference (P > 0.05). Moreover, no differences were noted in MG, CA, AW, and AOT among the three groups (P > 0.05). All the measurements in the three groups showed no significant change after porcelain/glaze firing (P > 0.05), except for MG in Group A, which significantly decreased (P < 0.05).

CONCLUSIONThe marginal fits of the double-layer crowns with full circumferential zirconia-collar and the anatomic single-layer zirconia crowns were superior to that of the double-layer crowns with regular margins. The MG of the crowns with regular margins was obviously influenced by porcelain firing.

Computer-Aided Design ; Crowns ; Dental Porcelain ; Dental Prosthesis Design ; X-Ray Microtomography ; Zirconium

OBJECTIVETo evaluate the effect of different auxiliary resistance forms on the resistance and marginal fitness of complete crowns for short molar preparations.

METHODSA total of 70 Nissin resin teeth were prepared with 20° total occlusal convergence, 2.5 mm of occlusocervical height, and a shallow finish line on a milling machine. The milled preparations were then randomly assigned to 7 groups of 10. The first group was used as the control group. A total of 30 dies were modified by preparing interproximal grooves with angles of 0°, 6°, and 20° centered on the mesial and distal surfaces of the dies. The rest of the teeth were prepared with occlusal holes in the center of the occlusal surface milled with the same burs to form 0°, 6°, and 20° holes. Cobalt-chromium copings were fabricated for all specimens. The marginal gap of specific points on the axial surface was measured before and after cementation. The resistance of each specimen was evaluated by applying an external force at an angle of 45° to the long axis of the die by using a universal testing machine in a lingual to buccal direction. The maximum force applied before crown dislodgement was measured. Data were analyzed using the SAS 9.2 software.

RESULTSThe results showed that the 0° groove, 0° hole, and 6° hole were effective in improving the resistance of the complete crowns (P<0.05). The 0° groove, 6° groove, 0° hole, 6° hole, and 20° hole had significant difference with the control group in terms of marginal discrepancies (P<0.05).

CONCLUSIONAuxiliary resistance forms with less degree indicate greater resistance force but worse marginal fitness. In clinical practice, if the resistance of a preparation is enough, the auxiliary resistance forms should be avoided from being used.

Cementation ; Crowns ; Dental Prosthesis Design ; Dental Prosthesis Retention ; Humans ; Molar ; Tooth Crown

OBJECTIVEThis study aimed to investigate the influence of coping material and porcelain firing on the marginal and internal fit of computer-aided design/computer-aided manufacturing (CAD/CAM) of zirconia ceramic implant- and titanium ceramic implant-supported crowns.

METHODSZirconia ceramic implant (group A, n = 8) and titanium metal ceramic implant-supported crowns (group B, n = 8) were produced from copings using the CAD/CAM system. The marginal and internal gaps of the copings and crowns were measured by using a light-body silicone replica technique combined with micro-computed tomography scanning to obtain a three-dimensional image. Marginal gap (MG), horizontal marginal discrepancy (HMD), and axial wall (AW) were measured. Statistical analyses were performed using SPSS 17.0.

RESULTSPrior to porcelain firing, the measurements for MG, HMD, and AW of copings in group A were significantly larger than those in group B (P < 0.05). After porcelain firing, the measurements for MG of crowns in group A were smaller than those in group B (P < 0.05), whereas HMD and AW showed no significant difference between the two groups (P > 0.05). Porcelain firing significantly reduced MG (P < 0.05) in group A but significantly increased MG, HMD, and AW in group B (P < 0.05) HMD and AW were not influenced by porcelain firing in group A (P > 0.05).

CONCLUSIONThe marginal fits of CAD/CAM zirconia ceramic implant-supported crowns were superior to those of CAD/CAM titanium ceramic-supported crowns. The fits of both the CAD/CAM zirconia ceramic implant- and titanium ceramic implant-supported crowns were obviously influenced by porcelain firing.

Ceramics ; Computer-Aided Design ; Crowns ; Dental Porcelain ; Dental Prosthesis Design ; Humans ; Titanium ; X-Ray Microtomography ; Zirconium

Objective To evaluate the quality of Psoralea corylifolia collected from 12 provinces of China.Methods An HPLCDAD-MS/MS method was used to identify,determine,and estimate 14 representative bioactive compounds in P.corylifolia.Then on the basis of the content data,the chemometrics method was used to differentiate 20 samples from different regions.Results The quality of P.corylifolia from 12 different provinces of China was evaluated by this method.Though the samples showed similar profiles,content of the detected markers varied significantly in different regions and batches.According to the results of the hierarchical cluster analysis and principle component analysis,it can be concluded that the samples from different origins could be clustered reasonably into two groups,as well as successfully distinguished.Conclusion A simple and reliable new method which used HPLC-DAD-MS/MS and chemometrics has been developed to characterize,classify,and control the quality of P.corylifolia.

Objective To evaluate the effects of Yangxue Qingnao Granules (YQG) in decreasing blood pressure in rats with renal hypertension and to investigate its mechanism.Methods Modified Goldblatt renal hypertension rat models were used.The rats were randomized into 6 groups: model group,YQG groups (treated with high-,moderate-and low-dose respectively),Captopril Tablets group and Niuhuang Jiangya Pills group, 10 rats in each group. The model group was given with distilled water and the other groups with corresponding drugs by gavage, once time a day. Blood pressure was detected in 1st, 2nd and 4th week after treatment. Four weeks after treatment plasma levels of endothelin (ET),calcitonin gene related peptide(CGRP) and nitric oxide(NO) were examined by radioimmunoassay.Results Plasma level of ET was increased and those of NO and CGRP were decreased in rats with renal hypertension. YQG could decrease ET level and increase the levels of NO and CGRP, high-dose YQG in particular (P

Objective To research the relation of early growth response gene-1(EGR-1) and NF-κB in human T-cell leukemia virus type 1(HTLV-1) Tax protein positive cells. Methods RT-PCR was used to amplify the aimed segments EGR-1 cDNA which was then inserted into an eukaryotic expression plasmid pcDNA3.0 to construct pcDNA3.0-EGR-1. The constructed plasmid was transfected into TaxN and TaxP cells by Tfx-50-mediated transfer method, the expression levels of EGR-1, p65 and Tax mRNA in transfected cells were assay by RT-PCR after 48 h post-transfection, the proteins of EGR-1 and p65 were detected by Western blot after 48 h post-transfection too. The constructed plasmid and pNF-κB-luc reporter gene plasmid was co-transfected into TaxN and TaxP cells by Tfx-50-mediated transfer method, and the activity of luciferase was assay after 48 h post-transfection. Results The results showed that the eukaryotic expression plasmid pcDNA3.0-EGR-1 was successfully constructed. The mRNA and protein expression of EGR-1 could be promoted significantly by Tax. EGR-1 can promote the mRNA and protein expressions of p65 in TaxP cells, the activity of NF-κB was up-regulated by EGR-1 too. Conclusion EGR-1 maybe involve in adult T-cell leukemia(ATL) by increasing the activation of NF-κB.

The particles suspended in seawater have great influence on pollutant migration and transformation in marine environment, while the lipophilic algae toxins enriched by the particles suspended in seawater will lead more serious toxicity to marine filter feeders. In this study, a new method was developed for the simultaneous determination of eight lipophilic algae toxins in suspended particles by ultra performance liquid chromatography-tandem mass spectrometry ( UPLC-MS/MS ) . After extracted with methanol by ultrasonic-assisted extraction, the sample was separated on an Acquity UPLC BEH C18 column (50 mm×2. 1 mm, 1. 7 μm) using gradient elution of acetonitrile and water containing 5 mmol/L ammonium acetate as eluent modifiers. The qualitative and quantitative analyses were carried out by electrospray ionization ( ESI) tandem mass spectrometry in multiple reaction monitoring ( MRM) mode. Under the optimal conditions, satisfactory precision (relative standard deviations (RSD≤14. 1%), recoveries (83. 8%-110. 4%) and detection limits (2. 9-103 pg/g) of the method were achieved. Good linearity (R2≥0. 99) was also obtained for all studied analytes. Then, the method was applied to determine the amounts of the eight lipophilic marine toxins in authentic suspended particle samples collected from Qingdao near-shore area. Pectenotoxin 2 ( PTX2 ) was detected in the samples from Shilaoren beach and No. 3 bathing beach with concentration ranges of 717 and 790 pg/g, respectively.

Objective To investigate the correlation between the degree of liver fibrosis and Aspartate aminotransferase-to-Platelet Ratio Index ( APRI ) in children with biliary atresia ( BA ) , and evaluate the clinical significance of liver fibrosis in biliary atresia.Methods A total of 97 patients with diagnosed BA were recruited between January 2010 and June 2013.AST, PLT and APRI were determined one week before laparotomy.The severity of hepatic tibrosis was.Judged by Metavir system the correlation among AST, PLT, APRI and severity of liver fibrosis were evaluated, and their diagnostic value for degree of liver fibrosis was analyzed by ROC.Results Sera AST levels and PLT counts of BA patients were found to be positively(r=0.367, P<0.01) and negatively(r=-0.403, P<0.01) correlated with Metavir scores of liver fibrosis, respectively.There existed positive correlation between APRI and the severity of hepatic fibrosis (r=0.541, P<0.01).The area under ROC curve of APRI to diagnose none or mild fibrosis and moderately severe fibrosis was 0.78, with sensitivity of 77.9%and specificity of 62.1%at the optimal cut-off value of 0.75; the area under ROC curve of APRI to diagnose moderately severe fibrosis with liver cirrhosis arrived 0.85, with sensitivity of 75.0% and specificity of 89.4% at the optimal cut-off value of 1.77.The accuracy of none or mild fibrosis, moderate fibrosis and cirrhosis diagnosed by APRI were 73.2%, 64.9%, 87.6%, respectively.Conclusion APRI can be used as a non-invasive parameter to assess the severity of hepatic fibrosis with BA.