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

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

Objective To construct the prokaryotic expression vector bearing fusion gene NT4-ADNF-9 and lay foundation for further study on genetic therapy of neuraseusory deafness. Methods By means of asymmetrical prince/ template, double stranded eDNA of activity dependent neurotrophic factor-9 (ADNF-9) was obtained, which included restriction enzymes sites on the two extremities. ADNF-9 eDNA was ligated to the signal and leader peptides of nenrotrophin 4 (NT4), and the fusion gene was named NT4-ADNF-9. Then it was suheluned into prokaryotic expression vector pBV220, and called pBV220/ NT4-ADNF-9. Results Evidences of DNA sequence analysis and restrtction enzymes digestion showed that we recombined ADNF-9 eDNA to the 3'terminal of the signal and leader peptides of NT4, and the fusion gene was subcluned into pBV220 successfully. Bioactivity of the products was proved that it could support the cell survival and neurite growth in the primary cultures of dorsal root ganglia (DRG) of embryonic day-8 cbicken neurons as compared to the control. Conclusion Prokaryotic expression vector pBV220/NT4-ADNF-9 can be constructed successfully and the bioactivtty is satisfactory.

Objective To prepare a kind of new lipid perfluorooctylbromide(PFOB) nanoparticles and to explore its potential application as an ultrasound contrast agent. Methods Lipid PFOB nanoparticles were prepared by microfluidization techniques. The morphology and distribution were observed with optical microscope and transmission electron microscope. Particle size and electric potential were determined with Malvern laser light scattering analyzer. Twelve normal Wistar rats were performed directly contrast imaging after injection of PFOB nanoparticles via caudal vein. Vital signs of the rats were monitored during the whole study. And eehogenie intensity of the liver was dynamically quantified through DFY ultrasound quantified analysis system. The mechanism of enhancement was studied by the frozen sections of rat's liver and spleen. Results The nanoparticles size and distribution were highly uniformed. The grey scale ultrasound imaging of the rat's liver and spleen were enhanced by PFOB nanoparticles. Ten seconds after PFOB nanoparticles injected,enhancement of liver began, the peak time was approximately 3 - 4 min, the duration of contrast enhancement was nearly up to 1 h, The enhancement of spleen was more significant and the duration was much longer. No abnormal changes of the rat's vital signs appeared during the study. Frozen sections suggested that PFOB nanoparticles accumulated in the liver and spleen was the potential mechanism of enhancement. Conclusions This novel and safe lipid PFOB nanoparticles could make prolonged enhancement of rat's liver and spleen,which has a good potency for ultrasound application.

Balloon Occlusion ; Esophageal and Gastric Varices ; Humans ; Polyethylene Glycols ; Sclerotherapy

BACKGROUND:Tantalum rod implant technology is a new method of early osteonecrosis treatment. Current research on stress distribution before and after tantalum rod implant in different sizes of femoral head necrosis area is few. OBJECTIVE:To analyze the stress distribution before and after tantalum rod implantation in different sizes of necrotic femoral head area using three-dimensional finite element method. METHODS:Three-dimensional finite element models of normal femoral head and necrotic femoral head of 15, 20 and 30 mm diameterwere constructed. Eight measuring points were chosen on two tiers of each necrotic model to detect the stress distribution and its alteration before and after tantalum rod implantation. RESULTS AND CONCLUSION:(1) Stress concentration werefound on every necrotic femoral head, most pronounced on the one with 30 mm lesion. (2) Tantalum implant appeared to reduce the stress concentration generaly. Comparison of the peak points of these models indicated most significant benefit in 15 mm lesion, next in 30 mm lesion, last in 20 mm lesion. (3) Results indicate that larger lesion entails more concentrated stress distribution and more likely to colapse. Tantalum rod implantation can delay the development of necrosis of the femoral head, andismost effective in smal lesion.

Objective To realize medical information collection and digital management in field battle and the fundamental information and cure of medical staff of emergency medical, equipment and the wounded were included in it. Methods The collecting information were transmitted to computer through wireless connection and manage the information with Delphi7 procedure. Results The system was used firstly in large-scale practice and completed the information transcription and management on elementary and cure in hundred of wounded. Conclusion The information is up to the mustard of field and it has established base on cure information in digital management.

Objective To collect and analyze the basic information of two dimensions electronics medicine tag, and send out the analytical information to field battle information management system and share with the resources. Methods The information were collected, analyzed and sent by adopting MC50 and some software. Results The information of collection and analysis on 80 cases was completed by the device in large-scale practice. Conclusion The device usage is convenient, the function is stable, and the rate of collection and analysis is 100%.

Objective: To investigate the expression of suppressor of cytokine signaling 2 (SOCS2) in breast carcinoma tissues and to discuss its relationship with clinical pathological data of breast carcinoma patients. Methods: The tissue microarray for 171 cases of breast carcinoma specimens, 18 adjacent tissues and 20 breast benign lesions were established. Then the expression of SOCS2, ER, PR, cerbB2, p53 and Ki-67 was detected by tissue microarray technique and S-P immunohistochemistry. Results: Positive rates of the SOCS2 protein in the breast carcinoma specimens, adjacent tissues and breast benign lesion were 57. 89% (99/171), 94. 44% (17/18), and 75% (15/20), respectively. The expression of SOCS2 was significantly different in breast carcinoma tissues of different TNM classification, different histological grades, and with or without Ki-67 expression and lymphatic metasrasis(P

Hypoxiaisoneofthemostimportantfactorsinfluencingcancertherapyandclinicalprogno-sis.With positron emission tomography (PET)widely adopted in clinical practice,the development and appli-cation of PET hypoxia imaging agents has been much popular in the field currently.PET hypoxia imaging can detect tumor hypoxia region noninvasively,which has important significance for optimizing cancer treatment decisions and improving the prognosis of cancer.