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

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 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.

ObjectiveTo summarize the clinical features of ulcerative eolitis (UC) complicated by toxic megacolon for early diagnosis and proper treatment. MethodsSix cases of toxic megacolon in the patients suffered from UC in Peking Union Medical College Hospital from 1983 to 2010 were analyzed,and related literature was searched and reviewed.ResultsThe incidence of the toxic megacolon in the patients with UC in our center was 0.7％ (6/824),which was lower than those reported in the literature.There were always risk factors triggering the disease.The prognosis of the patients was poor,even after medical care and surgery intervention.Evaluation of the patients and making right timing to perform the surgery would improve the prognosis of the patients in foreign literature. ConclusionIt's crucial to make early diagnosis of the toxic megacolon in the patients suffered from UC. The right choice and timing to perform urgent surgery or selective surgery may improve their prognosis.

Objective To explore the variation and clinical significance of growth hormone(GH) and insulin like growth factor-Ⅰ(IGF-Ⅰ) in children with critical disease.Methods One hundred and twenty-two cases were recruited into the study,among which 42 cases were sepsis in paediatric intensive care unit (sepsis group),20 cases had finished the cardiopulmonary bypass surgery without infection (surgery group).Sixty healthy children served as control group.Serum levels of GH and IGF-Ⅰ were deteced with immunochemiluminometric assay.Results The serum levels of GH were (6.71 ± 6.62) ng/ml in sepsis group,(8.86 ±8.06) ng/ml in surgery group,(3.87 ± 3.31) ng/ml in control group.Compared with the control group,the serum levels of GH in sepsis group and surgery group were increased significantly (P ＜ 0.05).There was no significant difference between sepsis group and surgery group.The serum IGF-Ⅰ levels were (63.72 ±54.17) ng/ml in sepsis group,(119.06 ± 102.12) ng/ml in surgery group and(154.22 ± 107.10) ng/ml in control group separately.The serum IGF-Ⅰ level of sepsis group was significantly decreased compared to the other two groups (P ＜ 0.05).There was no significant difference between surgery group and control group (P ＞0.05).In sepsis group,compared with those who died,the GH of the survival showed no significant difference,IGF-Ⅰ was significantly increased.(P ＜ 0.05).Conclusion GH playes a positive effect in patients with critical disease.IGF-Ⅰ decreases greatly in patients with serious infection.It suggests that IGF-Ⅰ could be a sensitive marker for reflecting whether there is serious infection.The sharply decreasing of IGF-Ⅰ may predict a bad outcome.

Objective To understand the fairness of health resources of endemic diseases institutions in Henan Province,to provide evidence for endemic allocation of health resources for the government.Methods Health-related data resources in endemic disease prevention and control institutions were collected in Henan Province,including personnel,business space area,the value of equipment,and health funding,etc.The percentages of population distribution and geographical distribution of health resources were calculated; Lorenz curves of demographic fairness and geographic fairness were drawn.According to Lorenz curve (Gini coefficients of the population and the geographical distribution were calculated based on Lorenz curve),Gini coefficients were used to evaluate the fairness of the endemic disease prevention institutions for health resource allocation.Results As can be seen from Lorenz curve,the population fairness of endemic disease prevention and health personnel was the best,but the number of senior officers was less and the total value of equipment owned was low.The geographical fairness of all the indicators of health resources was poorer,and geographic fairness among senior officers was the worst.The Gini coefficient of health technical personnel,senior personnel,undergraduate or above personnel,value of equipments,area of business room and health funding allocation determined by the population distribution was less than 0.4.The health resources were relatively fair and reasonable according to the distribution of population.The Gini coefficients of all the indicators determined by the distribution of geography were higher than those determined by the distribution of population.Furthermore,the geographic Gini coefficient of senior personnel was above 0.4 which was in the vigilance state.Conclusions The equality of health resources determined by population distribution in the institutions for endemic diseases control in Henan is superior to those determined by geographic distribution.The allocations of health resources of endemic diseases control in different areas are unbalanced.

Objective To compare the therapeutic effect of intraarticular injection with sodium hyaluronate (SH) and SH combined with triamcinolone acetonide for osteoarthritis (OA) of knee joint.Methods Eighty-two patients with OA of knee joint were divided into two groups by toss a coin from March 2010 to March 2011.Forty-two patients simplely accepted SH injection (SH group),40 patients accepted SH combined with triamcinolone acetonide (combination group).Intraarticular injection was taken once a week,a total of 5 times.Efficacy measurements included visual analog scale (VAS) for pain and safety.Results After treatment for 1 week,the measured value of VAS for up and down stairs in combination group was significantly lower than that in SH group [ (22.6 ± 6.1 ) mm vs.(63.9 ± 5.8 ) mm] (P ＜ 0.05 ).After treatment for 3,6 months,the measured value of VAS for up and down stairs in two groups had no significant difference [ (42.2 ± 6.6) mm vs.(41.1 ± 5.3) mm,(48.5 ± 5.5) mm vs.(49.3 ± 6.2) mm] (P ＞ 0.05).Function of the knee joint after treatment was better than before treatment in two groups.Adverse effects were minimal. Conclusions Intraarticular injection of SH and SH combined with triamcinolone acetonide OA of knee joint is a safe and effective method.SH combined with triamcinolone acetonide can improve the efficacy in early period.

Objective To investigate the effect of di-2-ethylhexyl phthalate (DEHP) on the proliferation of SK-N-SH human neuroblastoma cells and its underlying mechanism. Methods Cells were cultured in estrogen-free improved Dulbecco's Modified Eagle's Medium and then divided into 5 groups: no treatment (control group); treated with 17β-estradiol (E_2 group); treated with DEHP (DEHP group); treated with both E_2 and phosphatidylinositol-3-kinases (PI3K) inhibitor LY294002 (E_2 + LY294002 group); treated with both DEHP and LY294002 (DEHP + LY294002 group). The absorbance value (AV) was measured on day 0, 2, and 5. DNA proliferation index (PI) and apoptotic index (AI) were determined by flow cytometry on day 5. Caspase-3 protein, protein-serine-threonine kinase (Akt) and phosphor-Akt (Ser473) protein expression were analyzed by Western blot on day 5. Results The AV of All groups increased on day 2, and 5. The AV of E_2 and DEHP groups were higher than that of the control group (P<0. 001), but the AV of E_2 + LY294002 and DEHP + LY294002 groups were lower than those of E_2 and DEHP groups (P<0.01) on day 2 and 5. On day 5, PI of E_2 and DEHP groups were also higher than that of control (P<0.01). However, PI of E_2 + LY294002 and DEHP + LY294002 groups were lower than those of E_2 and DEHP group (P<0.01) on day 5. There was no significant difference in AI and caspase-3 protein expression among the groups. At the same time, phosphor-Akt (Ser473) protein expression of E_2 and DEHP groups increased obviously, compared with the control group. Compared with E_2 and DEHP groups, E_2 + LY294002 and DEHP + LY294002 groups decreased significantly. However, Akt protein expression was equal among those groups. Conclusions DEHP can promote the growth of SK-N-SH cells to a level similar to that of E_2, with activation of the PI3K/Akt signaling pathway.

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