Objective To evaluate the clinical effect of the use of pathfile and protaper nickel-titanium instruments for machine in root canal preparation.Methods A total of 200 patients suffering from pulpitis and periapical that needs root canal treatment was randomly divided into two groups according to treatment order (100 patients/each group).The experimental group was used pathfile and protaper in root canal preparation,and filled with warm gutta vertical condensation.The control group was used protaper root canal preparatory standards method,and filled with warm gutta vertical condensation.The required time of two sets of root canal preparation and the number of equipment broken were recorded,and X-ray film at the preoperation intraoperation and postoperation were used to evaluate effect of preparation and root filling.Results In the root canals prepared of the two groups,no issued offset,no side wear,no step-forming,and no position changed of the apical foramen were occurred,which was consistent with preperative X-ray film.One case was occurred fracture of instrument in the experimental group and the control group,it was Slfile.Tooth position was right mandibular,second molar nearly the root apical 1/3,and upper left second molar mesial buccal root apical position.The root canal preparation time of experimental group was significantly shorter than the control group[the front teeth:(4.73 ± 1.12) min vs (6.32 ± 1.84) min,t =2.243,P ＜0.05; the premolars:(7.83±1.23)min vs (10.25±2.68)min,t =2.475,P ＜0.05; the molars (10.14 ± 1.18) min vs (15.43 ± 5.94) min,t =2.991,P ＜ 0.01].Postoperative X-ray showed that 2 cases were occurred small amount of paste overfilled,the root canal closed tight,no less filling; and 3 cases of the control group occurred paste overfilled,no less filling too.Conclusions The use of nickel-titanium instruments pathfile and protaper for machine in root canal preparation is feasible,and improves the efficiency of root canal preparation.

Objective To investigate the possibility of pulp regeneration of different irreversible pulpitis with absorbable gelatin sponge as the scaffold,and dental seed cells,induced molecules and MTA closed.Methods 150 patients with irreducible pulpitis,who were removed the crown infection pulp and retained the root living pulp,according to the visiting sequence,were randomly divided into two groups.The experimental group was given absorbable gelatin sponge as the scaffold and MTA closed.The control group was given calcium hydroxide coverage.The symptoms situation and pulp situation were observed.Results 6 months after surgery,the success rate of acute pulpitis and chronic closed pulpitis in the experimental group was 76.5％ and 47.0％,which were significantly higher than those of the control group (14.3 ％,8.8％) (P ＜ 0.01).In the experimental group,the success rate of chronic hyperplastic pulpitis and chronic ulcerative pulpitis was 33.0％ and 35.0％,which were higher than those of the control group(9.1％,6.0％),but the differences between the two groups were not statistically significant (P ＞ 0.05).Conclusion Pulp regeneration in vivo is possible with absorbable gelatin sponge as the scaffold and MTA,pulp regeneration of acute pulpitis and chronic closed pulpitis are more likely to induce.

BACKGROUND: Axial-flow blood pump is a main pump for ventricle assistance. Previous researches demonstrate that poor hemocompatibility of blood pump is an important factor for hemolysis and thrombus.OBJ ECTTVE: To design an axial-flow blood pump based on previous kinds of blood pumps through changing whole appearance and impeller shape of the pump by using Computer-Aided Design CAD) and Computational Fluid Dynamics (CFD), and manufacture it successfully.DESIGN: Rationality of theoretical design was verified by practical tests.SETTTNG: Beijing Anzhen Hospital of Capital University of Medical Sciences Department of Biomedical Engineering,Beijing Institute of Heart, lung and Blood Vessel Diseases; the Faurteenth Institute of China-Aerospace Science and Industry Corporation.MATERIALS: Body of blood pump and impeller were titanium alligation, and shaft bearing was ceramic. Test in vitro was accorded to artificial ventricular assist device which was provided by Department of Biomedical Engineering, Beijing Anzhen Hospital of Capital University of Medical Sciences. Experimental goats were provided by Experimental Animal Center, Beijing Anzhen Hospital of Capital University of Medical Sciences.METHODS: Since the beginning of 2005, a model of axial flow blood pump was designed in the 14th Institute of China-Aerospace Science and Industry Corporation base on decreasing shearing force and circulating dead bands. In the process, CAD and CFD were used to generate the geometrical data document of pump's structure, which included the figures of pump's body, shape and number of impeller's vanes, the structure and position of the guide vanes, and the size of impeller's screw-pitch. And then, NC machine tool was used for shaping. Finally, axial-flow blood pump was fixed on artificial ventricular assist device which was provided by Department of Biomedical Engineering, Beijing Anzhen Hospital of Capital University of Medical Sciences. The pump's hemodynamic output was 5 L/min and the average pressure was 13.3 kPa under the mixture of glycerin and water and fresh anticoagulation goat blood. The samples were collected at every one half hour during pumps being pumping for 4 hours. According to testing pressure output of blood pump, normalized index of hemolysis (NIH) was used to reflect content of free hemoglobin in plasma, observe thrombogenesis in pump and verify pump's hemodynamic output and vascular damaging degree.RESULTS: Shaped axial-flow blood pump included body, impeller, guide vanes, ceramic shaft bearing, export and import. The volume was 63 mL. Experimental results in vitro indicated that when the rotation speed of blood pump was 10 000 r/min, its pressure and flow output were 21.01 kPa and 6.0 L/min. The hemodynamic output might satisfy for left ventricular assistance. Surface temperature did not change obviously during successive rotation. The calculation indicated that most parts in blood pump showed a streaming flow. The mean NIH was (0.047±0.017) g/100 L, which was less than that of previous pumps; while, thrombogenesis was not observed in blood pump.CONCLUSTON: Axial-flow blood pump designed by using CAD and CFD can not only satisfy for the hemodynamics of a left ventricular assistant devices, but also the blood damage is milder than previous pumps. Therefore, axial-flow blood pump improves blood compatibility.

Objective:To explore the accuracy and clinical effect of computer navigation system in locating the tunnel position in anterior cruciate ligament (ACL) reconstruction.Methods:A retrospective case-control study was conducted to analyze clinical data of 60 patients with ACL rupture treated in Daping Hospital of Army Military Medical University from March 2017 to March 2018, including 44 males and 16 females, aged 15-48 years (mean, 26.3 years). Computer navigation system was used to locate the internal orifice of intra-articular femoral and tibial tunnel in 30 patients (navigation group), and artificial location of intra-articular femoral and tibial tunnel in 30 patients (control group). The operation time and complications of two groups were recorded after operation. The tunnel position was evaluated by CT three-dimensional reconstruction, and the ratio of the tunnel position on the lateral surface of the femoral condyle to the tibial platform was evaluated by the grid method. The proportion sites from the deep posterior edge of lateral intercondylar surface of the femur to the shallow anterior edge (DS) and from the upper edge to the lower edge (HL) were used to represent the position of the femoral tunnel, and the proportion sites of the line connecting the anterior and posterior edge of the tibial plateau were used to represent the tibial tunnel position. The postoperative tunnel position was compared between the two groups. The knee joint stability (Lachman test, pivot shift test) and knee joint function score (Lysholm score, Tegner score) were compared between the two groups before operation and 12 months after operation.Results:All patients were followed up for 12-24 months (mean, 15 months). The operation time was (56.1±8.1)minutes in control group versus (76.0±6.7)minutes in navigation group ( P<0.05). In navigation group, 2 patients had skin edge necrosis at the place where the navigation needle was installed. The proportion of DS in femoral tunnel was (27.2±3.7)% in navigation group versus (33.9±4.4)% in control group ( P<0.05). HL proportion site was (36.6±4.8)% in navigation group versus (38.9±4.9)% in control group ( P<0.05). Proportion of the tibial tunnel at the anterior and posterior edge of the tibial plateau was (44.9±1.8)% in navigation group and (44.7±3.0)% in control group ( P>0.05). Both groups showed significant improvements in Lysholm score, Tegner score, Lachman test and pivot shift test 12 months after operation compared to the preoperative levels ( P<0.05), but the knee joint function score and knee joint stability score had no significant difference between the two groups 12 months after operation ( P>0.05). Conclusions:No significant differences are found between computer navigated and manually navigated ACL reconstruction with regards to knee joint stability, knee joint function, and tibial tunnel localization. However, computer assisted navigation enables the location of the lateral femoral tunnel closer to the anatomical position.