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OBJECTIVE@#To evaluate the influence of an epoxy resin-based sealer on the bond strength of adhesive resins to dentin and the cleaning efficacy of different solvents in removing sealer residues.@*METHODS@#The occlusal enamel of 25 freshly extracted human third molars without caries were removed to expose flat surfaces of dentin. The teeth were randomly divided into five groups according to the treatment received: For negative control group, the dentin surfaces were not contaminated with AH-Plus; For the other 4 experimental groups, the samples were contaminated with AH-Plus for 5 min and different measures were taken: For positive control group, the sealer were wiped with dry cotton pellets; For solvents experimental groups: cotton pellets saturated with 95% (volume fraction) ethanol, 99.5% (volume fraction) acetone or 99% (volume fraction) amyl acetate were used to wipe the sealer until the surface appeared clean when viewed through a stereomicroscope under ×10 magnification, then rinsed with de-ionized water for 3 s. After sealer removal, a self-etching adhesive system was applied on the surfaces with resin composite. The samples were sectioned into 1.0 mm×1.0 mm stick specimens (n=45) for microtensile test. Failure modes at the dentin-resin interface were observed using a stereomicroscope. The samples were sectioned into 1.0 mm piece specimens (n=4) for scanning electron microscope observation. The microtensile bond strength data were analyzed by one-way ANOVA. Chi-square test were used to analyse the failure modes between the groups.@*RESULTS@#There was significant difference among the five groups (P<0.001). For dry cotton pellet group (38.69±8.60) MPa and the ethanol group (37.14±12.01) MPa, the microtensile bond strength significantly declined when compared with negative control group (43.86±7.99) MPa (P<0.05). No significant difference of bond strength was found between the dry cotton pellet group and the ethanol group (P=0.426). There was no statistical significant difference among acetone group, amyl acetate group and negative control group (P>0.05). The bond strength of acetone group and amyl acetate group were (45.94±10.37) MPa and (43.99±7.01) MPa, respectively. The ethanol group exhibited lower bond strength than that of acetone group and amyl acetate group (P<0.05). Scanning electronic microscope observation revealed that in dry cotton pellet group and ethanol group, the resin tags were short and loose. Moreover, sealer residues were identified in the interface in the ethanol group samples, while the resin tags in the acetone and amyl acetate group were as dense and uniform as in negative control group. The distribution of failure modes showed no significant difference in the five groups (P=0.086).@*CONCLUSION@#The microtensile bond strength of dentin to composite resin was lower after exposure to sealer. Compared with ethanol and dry cotton pellets, the cleaning effect of acetone and amyl acetate on sealer-contaminated dentin surface were better.
Subject(s)
Humans , Composite Resins , Dental Bonding , Dental Stress Analysis , Dentin , Dentin-Bonding Agents , Materials Testing , Microscopy, Electron, Scanning , Resin Cements , Solvents , Tensile StrengthABSTRACT
Objective To provide basis for routine fetal cardiac screening by comparing the ultrasound detection rate of fetal heart defects between the high-risk and low-risk population.Methods According to the questionnaire about maternal risk factors,all 7165 pregnant women were divided into two groups.The high-risk group included 2147 cases and the remained 5018 were considered as low-risk population.Routine fetal heart screening was performed by the four-chamber view,left and right outflow tract views.If some cardiac malformations were found,the detailed fetal echocardiography would be performed.Both the detection rate of fetal cardiac defects and distribution of the relevant risk factors were analyzed.Results Ninty-five(1.33%)cases of congenital heart disease were found in our study,32(1.49%)cases from highrisk group and 63(1.26%)cases from low-risk group.No significant was found between the two groups (X2=0.635,P＞0.05).Karyotyping were performed prenatally in 23 of 95 fetal congenital defects cases by cordocentesis and chorionbiopsy,and 11(47.83%)cases of concomitant chromosomal abnormality were found.Conclusions Routine fetal screening for congenital fetal diseases should be performed in non-selected population for the similar detection rate of fetal defect in high-risk and low-risk group.
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Objective To evaluate the value of tomographic ultrasound imaging(TUI)in the fetal heart screening.Methods One hundred and ten volume datasets acquired from normal fetal heart in the second trimester with spatio-temporal image correlation(STIC) were evaluated offline with TUI. The Bmode and CDFI static images as well as the dynamic loops of one cardiac eycle could be reviewed simultaneously. The visualizing rate and ultrasonic scores of the 4 chamber view,outflow tracts and 3 vessels (and trachea)view obtained from TUI and routine ultrasonography for fetal heart screening were respectively compared. Results Among all 110 cases,the visualizing rate of 4 chamber view,outflow tracts and 3 vessels(and trachea) view were respectively 100%(67),88.9%(45),80.0%(45),84.4%(32)in Bmode and 100%(33),86.2%(25),50.0%(14),100%(4)in CDFI under the same fetal Dositi.n.No significant differences of the visualization rate were found between TUI and routine screening either in Bmode or in CDFI(P＞0.05). The median score of 4 chamber view of TUI in B-mode was little higher than that in routine screening,while the right outflow tract of screening in CDFI significantly higher than that of TUI(P＜0.05). Conclusions The visualizing rates and qualities of TUI are sufficient for fetal heart screening offline as well as routine ultrasonography online in second trimester.
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Objective To investigate the correlation risk factors of diabetes over 16-year-olds at the community level in Chongqing and to set a quantitative criteria for determining risk for diabetes and to identify persons having potential risk.Methods 1981 cases with 1:2 matched controls were chosen from five communities in Chongqing including Shapingba,Xiaolongkan,Tianxingqiao,Yubei Road,Ciqikou,which were interviewed with a uniformed questionnaire.The risk factors of diabetes mellitus were analyzed with logistic regression,and to calculate the odds ratios of risk factors for diabetes.Different levels of risk exposure factors were converted into a risk scores,using statistical models.Results An individual health risk appraisal model of diabetes was established,applicable to individuals of different sex,age,health behavior,disease,and family history,for men,13 risk factors including hyperlipidemia(14.995),coronary heart disease(6.689),family history of hypertension(4.005),smoking(3.111)etc.while for women,hyperlipidemia(12.426),family history of hypertension(3.986),stroke(2.714),liking sweets(1.244),about 15 risk factors,were entering the main effect model.The related risk scores were added to obtain a combined risk score to predict the individual's risk of diabetes in the future.Conclusion The incidence of diabetes could be effectively reduced by changing the unhealthy lifestyle and curing the patient with the disease.Evidence was provided to persuade people change their unhealthy lifestyles and behaviors through health education.The results could also be used in community to improve their health services.
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<p><b>OBJECTIVE</b>To explore the clinical application of real-time three-dimensional ultrasonography in the routine scanning of normal fetal heart.</p><p><b>METHODS</b>A total of 110 volume datasets of normal fetal hearts in the second trimester were acquired by spatio-temporal image correlation (STIC). An off-line analysis of acquired volume datasets was performed to examine each segment of fetal heart with tomographic ultrasound imaging (TUI) and dynamic multi-planar mode (MP). The re-slice images of four-chamber view, ventricular outflow tract views, and the three vessels plane were viewed with TUI. The quality of images obtained from TUI was compared with the conventional 2D imaging mode. The volume datasets were displayed interactively with MP as a series of three-orthogonal planes. The dynamic loops of one cardiac cycle were preformed by navigating the pivot point and rotational axis and shifting each re-slice image plane inside the volume datasets.</p><p><b>RESULTS</b>Satisfactory gray-scale volume acquisitions were accomplished in 110 cases. The average STIC scanning time of fetal heart was (55 +/- 15) s. An offline analysis showed that four standard planes of 2D routine screening for fetal hearts were easily obtained by TUI. The quality of the images derived from volume datasets were comparable to that directly obtained from 2D echocardiography. The visualization rate had no significant difference between TUI and routine 2D screening (P > 0.05). In MP mode, 39 cases with the starting plan of apical four-chamber view were obtained. Each segment of fetal heart was almost visualized off line, both in a frozen state and with heart in motion to fulfill sequential segmental analysis in fetal cardiac anatomy. The 72% - 100% main features of atria, ventricles, aorta, and the junction segments were viewed with MP by adjusting the three dimensional volume datasets, whose quality and contents met the expectations of off-line segmental analysis of normal fetal heart. A sagittal section of ventricular septum was obtained in the offline analysis, which was an unconventional view in 2D echocardiography.</p><p><b>CONCLUSION</b>Real-time three-dimensional ultrasonography can be applied for off-line segmental analysis of normal fetal hearts in the second trimester.</p>