Objective:To discuss the clinical feature and treatment of second mesiobuccal canal (MB2)of permanent maxillary molars. Methods:The root canals of 106 maxillary first molars and 80 maxillary second molars were explored with small size K files. The frequency and morphology of root canals were recorded. The canals of all cases were instrumented by Ni-Ti rotary instruments Hero 642, and obturated with lateral condensation technique. The efficiency of preparation and obturation was analyzed with radiographs before and after treatment. Results:The frequency of MB2 canal in maxillary first and second molars were 82.1% and 45.0%. Most MB2 was very fine and negotiated by size 8 or 10 file combined with EDTA. No transportation, ledge, or perforation was found except that one hand file was separated. Good result of treatment was achieved in most cases. Conclusion:The incidence of MB2 canals of maxillary first molars was higher than that of second molars, and most of them were very fine. The MB2 canals can be negotiated with small size file combined with EDTA, and shaped well with Ni-Ti rotary instruments.

Objective:To evaluate the shaping ability of nickel-titanium (NiTi) rotary instrument Hero 642 combined with SX of ProTaper in moderately and severely curved root canals.Methods:42 teeth with moderately and severely curved canals in 42 patients were prepared by Hero 642 and SX of ProTaper using crown-down technique and obturated with lateral condensation method. The efficiency of the preparation and obturation were analyzed by radiographs before and after treatment. Results:After preparation by the rotary instrument the original curvature and alignment of the canals were kept. No transportation, apical blockage, ledge or perforation was found in all cases. In one case,the file was broken during operation.After treatment light pain was complained in 4 cases and the pain alleviated and disappeared spontaneously. Conclusion:The NiTi rotary instrumentation technique with Hero 642 and ProTaper can be used to prepare curved root canals effectively and quickly.

BACKGROUND:Now experimental and clinical research on suitable bone substitutes for alveolar bone defects after dental implantation is an issue of concern.OBJECTIVE:To study the therapeutic effect of titanium core/bone morphogenetic protein (BMP) composite material on alveolar bone defects after immediate implant placement.METHODS:Twenty-four New Zealand rabbits were randomly assigned into normal group (no intervention),experimental group or control group.Animal models of bone femoral greater trochanter defect were made in the experimental and control groups.Dental implant and titanium core/BMP composite material were implanted in the experimental group,while dental implant and titanium core were implanted in the control group.Percentage of CD4+,CD8+ T lymphocytes,natural killer cell activity and interleukin 2 level were detected at postoperative 4 weeks;bone mineral density and osteogenesis around the implant were detected at postoperative 16 weeks through X-ray and histological examinations.RESULTS AND CONCLUSION:X-ray results showed that the bone mineral density in the experimental group was significantly higher than that in the control group (P ＜ 0.05).Histological results showed that in the experimental group,different degrees of cell lysis around the composite,more bone cells and bone matrices were found,implant-bone osseointegration formed well,and red-dyed mature bone tissues were detective inside the implant.Compared with the experimental group,lower number of bone cells and fibrocytes were found in the control group.Additionally,the percentage of CD4+ and CD8+ T lymphocytes,natural killer cell activity and interleukin 2 level in the experimental group were significantly lower than those in the control group (P ＜ 0.05).To conclude,the titanium core/BMP composite material can effectively repair alveolar bone defects after immediate implant placement to guide the growth of bone cells.

Objective To explore the effects of music therapy combined with acupuncture and auricular acupoint pressing in childbirth of primipara. Methods From June to December 2017,this study selected 90 primiparas with childbirth in Obstetrics Department at Zhejiang University Zhoushan Hospital as subjects by convenience sampling. All of primiparas were divided into intervention group and control group with the method of random number table,45 cases in each group. Control group adopted music therapy in which patients listened to their favorite music. On the basis of that in control group,intervention group carried out the acupuncture and auricular acupoint pressing. This study compared the Numerical Rating Scale(NRS),the time when the orifice of uterus ranged from 3 to 10 cm,neonatal Apgar score and blood loss two hours after childbirth of delivery women. Results There was no statistical difference in the score of NRS of primiparas between two groups when the orifice of uterus ≥3 cm(P>0.05). The scores of NRS of intervention group were lower than those of control group with statistical differences 30 min after analgesia and when uterus opened to the full(P<0.05). The time when the orifice of uterus ranged from 3 to 10 cm in intervention group was shorter than that in control group with a statistical difference(P< 0.05). There were no statistical differences in the neonatal Apgar score and blood loss two hours after childbirth of patients between two groups(P> 0.05). Conclusions Music therapy combined with acupuncture and auricular acupoint pressing can ease the labor pain,shorten the time when uterus opens to the full,and is safe for mother and baby and has better effects compared with simply music therapy which is worthy of being popularized and applied.

Objective To evaluate the diagnostic value of gray-scale ultrasound combined with contrast-enhanced ultrasound (CEUS) in thyroid imaging and reporting system ( TI-RADS) 3-5 nodules of American College of Radiology ( ACR) . Methods The 208 patients( 216 nodules) who underwent thyroid contrast-enhanced ultrasound examination from April 2014 to December 2016 were retrospectively analyzed . The ACR TI-RADS classification and contrast-enhanced mode of thyroid ultrasound were evaluated . The benign and malignant thyroid lesions were constructed through the analysis of contrast-enhanced mode of thyroid benign and malignant lesions in the past literature and the preliminary study of our group . Prediction model of gray scale combined with contrast-enhanced ultrasound for lesions were established . Besides ,the sensitivity ,specificity and accuracy of gray scale ultrasound combined with contrast-enhanced ultrasound prediction model for differential diagnosis of benign and malignant thyroid lesions were calculated based on the results of puncture biopsy or surgical pathology as the gold standard . Results Compared with pathological results , the positive predictive value , negative predictive value , accuracy , sensitivity and specificity of gray scale combined with contrast-enhanced ultrasound in evaluating thyroid nodules were 90 .8％ ,93 .3％ ,91 .2％ ,98 .8％ and 62 .2％ ,respectively . Conclusions Gray-scale ultrasound combined with contrast-enhanced ultrasound can provide clinical value in differential diagnosis of benign and malignant TI-RADS 3-5 thyroid nodules .

COVID-19 pandemic has put a huge burden on public health and global economy. Vaccines play an important role in controlling virus transmission and reducing mortality. While monoclonal virus neutralizing antibodies can reduce the viral load, improve symptoms, and prevent the aggravation of the disease from hospitalization. Now hundreds of clinical trials of COVID-19 vaccine and monoclonal neutralizing antibody are in progress. The vaccine focuses on disease prevention, while the neutralizing antibody focuses on disease treatment. There are quite many differences between the two kinds of clinical trials by following different technical guidelines, research purpose, trial design, implementation and outcome assessment. Therefore, it is necessary to summarize the similarities and differences between the clinical trials for the reference of new drug research and development as well as clinical researchers.