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.

Resident doctors participating in clinical teaching is a disputable topic.We analyze the current situation and difficulties in clinical teaching and propose the concept of RATS(residents as teachers) program in china aiming to strengthen the training of clinical teaching skills in residents and improving culture quality of resident doctors.And we also suggest the establishment of "clinical teaching data warehouses for resident doctors"to keep pace with requirements of our resident training program in new times.

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.

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.

Objective To investigate the consumption rate of non-iodized salt,and evaluate the iodine status and goiter prevalence among school children in high water iodine areas of Henan Province from 2014 to 2015.Methods In the 20 counties with high water iodine,one township was randomly selected from each location (east,west,south,north and middle) in each county;secondly,4 villages were selected from each chosen township;thirdly,15 households were selected to collect salt samples from each chosen village.In the 10 chosen counties,one village with high water iodine was selected and water samples were collected;one school was sequentially selected from the chosen village and 100 school children aged 8-10 were chosen to collect their urine samples and measure their thyroid volume.Salt iodine was tested by semi-quantitative method;iodine contents of urine and water were tested by arsenic cerium catalytic spectrophometry;thyroid volume was measured by ultrasound method.Results In the 20 counties with high water iodine,4 440 salt samples were collected and tested both in 2014 and 2015;the rates of non-iodized salt were 98.2％ (4 363/4 440) in 2014 and 98.3％ (4 366/4 440) in 2015.In the 10 chosen counties,the median water iodine contents from the chosen villages were 202.0 μg/L in 2014 and 235.0 μg/L in 2015;970and 999 urine samples of the students from the chosen villages were collected and tested in 2014 and 2015,and the median urinary iodine contents were 251.9 μg/L in 2014 and 290.6 μg/L in 2015;937 and 948 students were examined in 2014 and 2015,the goiter rates were 3.4％ (32/937) in 2014 and 7.8％ (74/948) in 2015.Stratified by water iodine,the urinary iodine contents and goiter rates of school children increased with the rise of water iodine content.When the water iodine content exceeded 300 μg/L,goiter rate of school children was 8.4％,which was higher than other groups (P ＜ 0.05).Conclusions After stopping the supple of iodized salt in high water iodine areas,the current iodine status and goiter rate of school children are still higher than normal levels.Both noniodized salt supply and water improvement to reduce water iodine content should be taken in the areas with water iodine higher than 150 μg/L.

Objective To investigate clinical significance of diagnosis of the anti saccharomyces cerevisiae antibody (ASCA), pancreatic acini antibody (PAB)resistance,resistance to small goblet cell antibody (GAB),anti neutrophil cytoplasm anti-bodies (ANCA)for inflammatory bowel disease (IBD)and the differential diagnosis of ulcerative colitis (UC)and crohn's disease (CD).Methods Collected 200 cases of test group sets of inflammatory bowel disease,serum by indirect immunofluo-rescence (IF).Results In the serum of 200 patients,106 cases with positive or weakly positive.Among them,the positive ASCA/weak positive 24 cases,14 cases of PAB,GAB 63 cases,28 cases ANCA,and included in ASCA group respectively and PAB group,GAB group,ANCA group.Positive rate of ANCA and GAB in the diagnosis of UC were 34% and 58%. Positive rate of ASCA and PAB in the diagnosis of CD were 28.6% and 38.1%.ANCA associated with GAB detection in the diagnosis of UC specific degree was 60%,ASCA associated with PAB detection in the diagnosis of CD specific degree was 75%.Conclusion Serum inflammatory bowel disease antibody spectrum in ASCA,ANCA,GBA and PAB four antibod-ies of joint detection has important guiding value to the diagnosis of IBD,also can be used as one of UC and CD in the differ-ential diagnosis methods.

Objective To analyze the results in neonatal hearing screening,and then to make diagnosis and intervention for neonates with hearing problems as soon as possible.Methods From January 2004 to December 2008,7 064 newborns at Shanghai East Hospital received hearing screening by distortion product oto-acoustic emissions (DPOAE) 2～4 days after birth.Re-screening tests were performed for infants who failed the initial screening 42 days after birth.Those newborns who failed again received further audiologic diagnostic evaluations 3 months afterwards.Results Among 7 064 cases screened,out of 6 412 normal newborns,579 (9.03%)failed the initial screening,and 38 (7.41%)failed re-screening.129 cases of the other 652 (19.79%) newborns in NICU failed the initial screening,and 20 cases (18.69%) failed re-screening.There were statistical differences between the passing rates of the two groups (P