BACKGROUND:At present, the confrontation of CAD/CAM systems and the lost wax casting method for marginal adaptation has been widely concerned, but the results are controversial. OBJECTIVE:To compare the marginal adaptation of single cobalt-chromium PFM crowns produced by 3 Shape CAD/CAM systems and the lost wax casting method. METHODS: A maxilary first premolar was prepared according to the standards. 50 resin-generation models were created by bi-color silicone rubber method and randomly divided into two groups: CAD/CAM group (A1-A25) and cast group (B1-B25). Al the models were cast in plaster. In CAD/CAM group, the digital impressions were obtained by optical scanning, then designed through computer and cut directly by NC miling machine. In cast group, metal ceramic crowns were made by the lost wax casting method. When crowns were al seated on the working dies, the marginal gaps were copied with light silicone rubber and then embedded with occlusal silicone rubber. The thickness of crown marginal gap was measured with a stereo microscope. RESULTS AND CONCLUSION:The average vertical clearance was (34.67±7.48)μm of CAD/CAM group, while (53.70±9.64)μm of the cast group; the difference was statisticaly significant between two groups (P < 0.05). The average level clearance was (37.61±7.63)μm of CAD/CAM group, while (53.02±10.65)μm of the cast group, and the difference was statisticaly significant between two groups (P < 0.05). Experimental findings suggest that, the marginal adaptation of single cobalt-chromium PFM crowns cast produced by 3 Shape CAD/CAM systems is clinical acceptable (< 120μm), and CAD/CAM systems of metal casting is obviously better than the lost wax casting in building metal based crowns with adaptable margin.

Objective To assess the feasibility of K value of dynamic contrast enhanced MRI (DCE-MRI) in evaluation of anti-angiogenic effects on nude mice with orthotopic transplantation tumor model of gastric cancer.Methods Nude mice with orthotopic transplantation tumor model of gastric cancer were randomly assigned to two groups:Treatment group (n =15),mice were given apatinib intragastrically for 18 days (100 mg/kg),and control group (n=15),mice were given ddH2O2 in the same manner.After 18 days,DCE-MRI was performed and K value was measured.Then the tumors were dissected from the adjacent tissues in order to detect the microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression levels.MVD and VEGF expression level were compared between treatment group and the control group.Results MVD (x2 =4.89,P＜0.05) and VEGF expression level (x2 =8.69,P＜0.01) of treatment group were much lower than those of control groups.The Kt value of treatment group was significantly lower than that of control groups ([0.63±0.05]/min vs [1.66±0.23]/min,t=17.05,P＜0.01).Conclusion The value of k in DCE-MRI can be utilized to assess the effects of apatinib on nude mice with orthotopic transplantation model of gastric cancer.

Objective To evaluate the value of post-processing techniquos of multi-slice spiral CT(MSCT) in diagnosis of small peripheral lung cancer. Methods 36 patients with small peripheral lung cancer(≤20mm in di-ameter) who had been proved by pathology were eoueeted. After MSCT scanning ,3D reconstruction images were made by MPR,SSD and VR,then compared with axial thin-slice images. Results The sensitivity of MPR on vascularnotch sign,lobulation and spiculated sign was higher than that of axial thin-slice images. The sensitivity of SSD on peural sign was higher than that of axial thin-slice images. The sensitivity of VR on vascularnotch sign and lobulation was higher than that of axial thin-slice images. Conclusion The post-processing techniques of MSCT have high value on diagnosis of small peripheral lung cancer. More information could be collected when many kinds of post-processing techniques were used.

Purpose To evaluate the feasibility of using dual-energy CT scanner to differentiate two contrast media bismuth and gadolinium. Materials and Methods Two phantoms containing contrast media of different ratio were scanned on dual-energy CT. Group 1 was mixture of iodine and gadolinium solution with volume ratio of 0∶1, 1∶6, 1∶1, 6∶1 and 1∶0. Group 2 was mixture of iodine and bismuth solution with mass ratio of 0∶1, 1∶6, 1∶1, 6∶1, 1∶0. Monoenergetic image reconstruction was performed at 80 keV. Liver VNC software was used for virtual scanning and iodine concentration analysis. Results Under 80 keV reconstruction, the measured CT attenuation of Group 1 was 379-383 HU, and 170-173 HU in group 2. The iodine concentration of two groups was not signiifcantly different between the calculated and actual iodine concentration (P>0.05). The dual-energy CT can distinguish two contrast media. Iodine and gadolinium contrast media were not statistically different, while iodine and bismuth contrast media agent could be easily differentiated. Conclusion Dual-energy CT can distinguish two contrast media with different attenuation.

Objective To investigate the anesthetic management of perventricular closure of ventricular septal defects (VSD) under transesophageal echocardiography. Methods A retrospective review of the clinical data of 52 children who underwent perventricular closure of VSD under transesophageal echocardiography were analyzed. All the children were performed tracheal intubation under general anesthesia, and the electrocardiogram, pulse blood oxygen saturation, invasive arterial pressure, central venous pressure, end tidal carbon dioxide partial pressure, temperature and urine output were continuously monitored throughout the procedure. The transesophageal echocardiography was necessary for guiding transcatheter or per-ventricular device placement. Results Perventricular closure of VSD was successfully completed in 51 children under transesophageal echocardiography, the operation time was (76.7 ± 36.4) min, the anesthesia time was (89.5 ± 27.1) min; 1 child was converted to open surgical repair. Conclusions The intraoperative transesophageal echocardiography technology is the key to the success of the surgery. At the same time of analgesia and sedation, the anesthesia doctor needs to pay attention to the changes of hemodynamics in children.

Objective To investigate the factors that influence the fermentation process of compound Chinese medicine and determining the optimum fermentation with single factor experiment and response surface methodology. Methods Through controlling the factors in the fermentation process of compound Chinese medicine (such as fermentation bacteria, fermentation time, fermentation temperature, inoculum amount, etc.), with its increase rate of total peak area as evaluation indicator, the alcohol extracts before and after fermentation were monitored and comparative evaluated by HPLC, and the optimum fermentation process was determined by response surface methodology. Results The fermentation process optimized by single factor experiment and response surface methodology was as follows:SZ-2 strain served as the fermentation bacteria, temperature was 33 ℃, inoculum amount was 4%, and time was 3.5 d, the average increase rate of total peak area was 31.24%. Conclusion HPLC can be used to identify and evaluate the fermentation of compound Chinese medicine under the different factors, and to clarify the optimal fermentation process by response surface methodology, which provide reference for the development of fermentation process.

Objective To evaluate the efficacy of CT in diagnosis of pulmonary blastoma (PB).Methods 10 patients with surgically and pathologically proved PB were collected in this study,and CT findings of the tumors were retrospectively analyzed. Results Of 10 cases,1 were central form (the tumors localized under pleura) and 9 was periphery form.The tumors were localized at right lobus in 6( including upper lobus,middle and lower lobus in 1,1 and 4,respectively) and left lobus in 4(upper lobus in 3 and lower lobus in one).The lesions were more than 3 cm in diameters in all cases.Necrosis of tumors were seen in 7 cases.The lesions had obvious enhancement after intravenous injection of contrast medium.Enlarged lymph nodes were identified at hilum of the lung and mediastinum in one,bony destruction and distant metastases were seen in one and 2,respectively.Conclusion PB is not of characteristic CT features,CT-guided percutaneous needle biopsy and the immunohistochemical method are helpful to the diagnosis of pulmonary blastoma.

Objective To explore the efficiency, complications and probability of preserving part renal function by local renal microwave ablation. Methods The fresh pig renal pelvis full filled with 30% diatrizoate meglumine and the dogs kidney taken arterial pyelography were both ablated with microwave. Dogs were divided into three groups: measuring temperature after ablation group, single point ablation both on the two kidneys group and double points ablation on unilateral kidney group. In measuring temperature after ablation group, DSA and pathology were performed immediately after ablation. In the other groups, DSA with blood and urine samplings were taken for routine tests including renal function right after the ablation and 10 days later. Results Experiment in vitro showed conspicuous renal pelvic contraction and convolution. The group under power rate of 70, 3 min produced urine leak easily. Preliminary test in vivo with DSA showed the disappearance of local kidney blood supply. The residual renal function was related to areas of necrosis. Acute stage pathology revealed acute renal cortex medulla and pelvic cells injury. DSA of chronic stage showed no change in size of the area of ablation. The blood supply of necrotic areas was not restored. The residual kidney possessed the excretion contrast medium with no urine leaks. Upper pole of right kidney adhered with adjacent tissue, together with thickened covering. Pathology revealed fibrous proliferation around the coagulative necrosis. Conclusion Microwave ablation can inactivate the local renal tissue, and, effectively preserve the big blood vessels and function of residual kidney. No urine leaks occurred in chronic stage but easily to produce adhesions with adjacent tissue.

Objective To evaluate the capability of virtual non-contrast (VNC)of the second-generation dual-source CT (DSCT), and to display the adipose tissue of gastric serosa.Methods 48 patients with gastric cancer undergoing preoperative DSCT and sur-gery were enrolled.The true non-contrast (TNC)values and VNC values of perigastric adipose tissue were measured and compared with conventional non-contrast scanning and VNC of arterial phase and venous phase.The VNC values of perigastric adipose tissue were compared between serosal involvement group and non-serosal involvement group.Results There was statistical difference be-tween TNC values and VNC values of perigastric adipose tissue (P <0.05),the absolute differences were under 13 HU.The differ-ence of VNC values between serosal involvement group and non-serosal involvement group was significant (P <0.05).Conclusion VNC of the second-generation DSCT can clearly display the adipose tissue of gastric serosa.It has certain capability in judging sero-sal involvement.VNC has the proficiency to replace conventional non-contrast scanning.

Objective To investigate the clinical utility of dual-energy virtual non-contrast CT(VNCT)of dual source CT in the di-agnosis and differential diagnosis of solitary pulmonary nodule(SPN).Methods Thirty-six patients with suspected SPN underwent chest plain single energy CT and dual-phase contrast enhanced CT (DECT)(25 and 90 s).The images of dual energy were sent to a commercial workstation for VNC image generation.CT values of SPN on VNC and true non-contrast(TNC),as well as signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were compared.The accuracy of calcification detection was compared according to the diameter and density of the calcification.The TNC images were used as the reference.Results CT values,SNR and CNR of VNC had no statistical difference among TNC and VNC at 25 s and 90 s(P >0.05).DECT VNC(5mm slice)could accurate detected calci-fication(diameter>2 mm,CT value>1 50 HU)in SPN.The 2 mm slice performed significantly better than 5 mm slice VNC images. Conclusion The VNC could provide consistent diagnostic information with TNC.The thin slice DECT VNC images can be used in clinical practice to replace TNC without losing small calcification in SPN,which has potential to reduce the patient radiation dose.