1.Preparation of Phenolic Acid-sodium Hyaluronate Copolymers and in vitro Antioxidant Activity Assessment
Xiao-Yue ZHANG ; Xiao-Na WANG ; Min JIANG ; Ting-Ting HAN ; Jin-Song GONG ; Qing-Na LI ; Su-Zhen YANG ; Jin-Song SHI
Progress in Biochemistry and Biophysics 2024;51(8):1950-1962
		                        		
		                        			
		                        			ObjectiveSodium hyaluronate (HA) was used as the research object to modify it with phenolic acid in order to obtain the molecular structure with better antioxidant activity or even new activity. MethodsIn this study, 5 kinds of phenolic acid-sodium hyaluronate was prepared by free radical-mediated grafting method, and the grafts with the highest grafting degree were selected to optimize the synthesis conditions. Then, grafts structure and physicochemical properties were analyzed. The grafts were characterized by IR, UV, 1H NMR, FESEM and TGA spectra. The in vitro antioxidant capacity of grafts was determined by the scavenging ability of DPPH·, ABTS+· and O2-·. ResultsAmong 5 kinds of phenolic acid-sodium hyaluronate, the grafting rate of ferulic acid-sodium hyaluronate copolymer (FA-HA) was highest , which was chosen as experimental sample in the following tests. Firstly, the reaction conditions were investigated and the highest grafting rate was (16.59±0.31) mg/g at the optimal preparation conditions. Then, FA-HA structure and physicochemical properties were analyzed. Data from UV, IR, 1H NMR analyses, TGA showed that FA were successfully grafted to HA. Compared with HA, the results of gel permeation chrematography (GPC) showed that the molecular mass distribution ofFA-HA copolymer decreased from 34.4 to 31.5 ku, but the uniformity of molecular distribution was improved. FESEM results showed that the structure of copolymer exhibited a closely connected lamellar structure with a relatively smooth surface. TGA results showed that thermal stability of FA-HA had a little decline. The antioxidant performance in vitro results showed that, during 0.25-10 g/L, FA-HA can eliminate (83.76±4.86)% DPPH·, (76.95±5.06)% ABTS+· and (83.08±2.51)% O2-· respectively at 10 g/L. which were higher than that of native HA and FA. ConclusionFA and HA were successfully grafted together by free radical grafting, and the grafted FA-HA had better antioxidant activity in vitro, which provided a theoretical basis for further research and development of phenolic acid-HA grafts. 
		                        		
		                        		
		                        		
		                        	
2.Associations of reproductive health indicators with lung function and COPD among female community residents aged 40 years and above in Songjiang District,Shanghai
Xin YIN ; Yi-Ling WU ; Shan-Shan HOU ; Jing LI ; Wei LUO ; Min-Jun YU ; Jin-Xin ZANG ; Wei WANG ; Xu-Yan SU ; Qi ZHAO ; Yin-Feng ZHU ; Gen-Ming ZHAO ; Yong-Gen JIANG ; Qing-Wu JIANG ; Na WANG
Fudan University Journal of Medical Sciences 2024;51(6):882-889
		                        		
		                        			
		                        			Objective To investigate the associations of reproductive health indicators with lung function and chronic obstructive pulmonary disease(COPD)among women aged 40 years and above.Methods From Jul to Sep,2021,female subjects aged 40 years and above were randomly selected from the Shanghai Suburban Adult Cohort and Biobank for COPD screening.A questionnaire was used to obtain information on demographic characteristics and reproductive health indicators.Linear regression was used to analyze the effects of reproductive health indicators on forced vital capacity(FVC)and forced expiratory volume in the first second(FEV1).Logistic regression was also used to analyze the effects of reproductive health factors on FVC as a percentage of the predicted value(FVC%Pred)and FEV1%Pred as well as on COPD.Results A total of 1876 women aged 40 years and above were enrolled with mean age of(62.1±8.2)years old,among them,78.1%were menopausal,and 40.9%had been pregnant≥3 times.Multivariate analysis showed that FVC and FEV1 decreased in postmenopausal women,but menopause was not associated with a decrease in their percentage of predicted values.Pregnancies≥3 times was a risk factor for COPD(for 3 times,OR=4.92,95%CI:1.48-19.95,P<0.05;for≥4 times,OR=9.06,95%CI:2.32-41.57,P<0.01),while pregnancies of 2 times did not increase the risk of COPD.Conclusion In women aged 40 years and above,menopause is associated with poorer FVC and FEV1,and excessive pregnancy(≥3 times)is a risk factor for COPD.
		                        		
		                        		
		                        		
		                        	
3.Changing resistance profiles of Enterococcus in hospitals across China:results from the CHINET Antimicrobial Resistance Surveillance Program,2015-2021
Na CHEN ; Ping JI ; Yang YANG ; Fupin HU ; Demei ZHU ; Yingchun XU ; Xiaojiang ZHANG ; Yi XIE ; Mei KANG ; Chuanqing WANG ; Pan FU ; Yuanhong XU ; Ying HUANG ; Ziyong SUN ; Zhongju CHEN ; Yuxing NI ; Jingyong SUN ; Yunzhuo CHU ; Sufei TIAN ; Zhidong HU ; Jin LI ; Yunsong YU ; Jie LIN ; Bin SHAN ; Yan DU ; Sufang GUO ; Lianhua WEI ; Fengmei ZOU ; Hong ZHANG ; Chun WANG ; Yunjian HU ; Xiaoman AI ; Chao ZHUO ; Danhong SU ; Dawen GUO ; Jinying ZHAO ; Hua YU ; Xiangning HUANG ; Wen'en LIU ; Yanming LI ; Yan JIN ; Chunhong SHAO ; Xuesong XU ; Chao YAN ; Shanmei WANG ; Yafei CHU ; Lixia ZHANG ; Juan MA ; Shuping ZHOU ; Yan ZHOU ; Lei ZHU ; Jinhua MENG ; Fang DONG ; Zhiyong LÜ ; Fangfang HU ; Han SHEN ; Wanqing ZHOU ; Wei JIA ; Gang LI ; Jinsong WU ; Yuemei LU ; Jihong LI ; Jinju DUAN ; Jianbang KANG ; Xiaobo MA ; Yanping ZHENG ; Ruyi GUO ; Yan ZHU ; Yunsheng CHEN ; Qing MENG ; Shifu WANG ; Xuefei HU ; Jilu SHEN ; Ruizhong WANG ; Hua FANG ; Bixia YU ; Yong ZHAO ; Ping GONG ; Kaizhen WEN ; Yirong ZHANG ; Jiangshan LIU ; Longfeng LIAO ; Hongqin GU ; Lin JIANG ; Wen HE ; Shunhong XUE ; Jiao FENG ; Chunlei YUE
Chinese Journal of Infection and Chemotherapy 2024;24(3):300-308
		                        		
		                        			
		                        			Objective To understand the distribution and changing resistance profiles of clinical isolates of Enterococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Enterococcus according to the unified protocol of CHINET program by automated systems,Kirby-Bauer method,or E-test strip.The results were interpreted according to the Clinical & Laboratory Standards Institute(CLSI)breakpoints in 2021.WHONET 5.6 software was used for statistical analysis.Results A total of 124 565 strains of Enterococcus were isolated during the 7-year period,mainly including Enterococcus faecalis(50.7%)and Enterococcus faecalis(41.5%).The strains were mainly isolated from urinary tract specimens(46.9%±2.6%),and primarily from the patients in the department of internal medicine,surgery and ICU.E.faecium and E.faecalis strains showed low level resistance rate to vancomycin,teicoplanin and linezolid(≤3.6%).The prevalence of vancomycin-resistant E.faecalis and E.faecium was 0.1%and 1.3%,respectively.The prevalence of linezolid-resistant E.faecalis increased from 0.7%in 2015 to 3.4%in 2021,while the prevalence of linezolid-resistant E.faecium was 0.3%.Conclusions The clinical isolates of Enterococcus were still highly susceptible to vancomycin,teicoplanin,and linezolid,evidenced by a low resistance rate.However,the prevalence of linezolid-resistant E.faecalis was increasing during the 7-year period.It is necessary to strengthen antimicrobial resistance surveillance to effectively identify the emergence of antibiotic-resistant bacteria and curb the spread of resistant pathogens.
		                        		
		                        		
		                        		
		                        	
4.Surveillance of antifungal resistance in clinical isolates of Candida spp.in East China Invasive Fungal Infection Group from 2018 to 2022
Dongjiang WANG ; Wenjuan WU ; Jian GUO ; Min ZHANG ; Huiping LIN ; Feifei WAN ; Xiaobo MA ; Yueting LI ; Jia LI ; Huiqiong JIA ; Lingbing ZENG ; Xiuhai LU ; Yan JIN ; Jinfeng CAI ; Wei LI ; Zhimin BAI ; Yongqin WU ; Hui DING ; Zhongxian LIAO ; Gen LI ; Hui ZHANG ; Hongwei MENG ; Changzi DENG ; Feng CHEN ; Na JIANG ; Jie QIN ; Guoping DONG ; Jinghua ZHANG ; Wei XI ; Haomin ZHANG ; Rong TANG ; Li LI ; Suzhen WANG ; Fen PAN ; Jing GAO ; Lu JIANG ; Hua FANG ; Zhilan LI ; Yiqun YUAN ; Guoqing WANG ; Yuanxia WANG ; Liping WANG
Chinese Journal of Infection and Chemotherapy 2024;24(4):402-409
		                        		
		                        			
		                        			Objective To monitor the antifungal resistance of clinical isolates of Candida spp.in the East China region.Methods MALDI-TOF MS or molecular methods were used to re-identify the strains collected from January 2018 to December 2022.Antifungal susceptibility testing was performed using the broth microdilution method.The susceptibility test results were interpreted according to the breakpoints of 2022 Clinical and Laboratory Standards Institute(CLSI)documents M27 M44s-Ed3 and M57s-Ed4.Results A total of 3 026 strains of Candida were collected,65.33%of which were isolated from sterile body sites,mainly from blood(38.86%)and pleural effusion/ascites(10.21%).The predominant species of Candida were Candida albicans(44.51%),followed by Candida parapsilosis complex(19.46%),Candida tropicalis(13.98%),Candida glabrata(10.34%),and other Candida species(0.79%).Candida albicans showed overall high susceptibility rates to the 10 antifungal drugs tested(the lowest rate being 93.62%).Only 2.97%of the strains showed dose-dependent susceptibility(SDD)to fluconazole.Candida parapsilosis complex had a SDD rate of 2.61%and a resistance rate of 9.42%to fluconazole,and susceptibility rates above 90%to other drugs.Candida glabrata had a SDD rate of 92.01%and a resistance rate of 7.99%to fluconazole,resistance rates of 32.27%and 48.24%to posaconazole and voriconazole non-wild-type strains(NWT),respectively,and susceptibility rates above 90%to other drugs.Candida tropicalis had resistance rates of 29.55%and 26.24%to fluconazole and voriconazole,respectively,resistance rates of 76.60%and 21.99%to posaconazole and echinocandins non-wild-type strains(NWT),and a resistance rate of 2.36%to echinocandins.Conclusions The prevalence and species distribution of Candida spp.in the East China region are consistent with previous domestic and international reports.Candida glabrata exhibits certain degree of resistance to fluconazole,while Candida tropicalis demonstrates higher resistance to triazole drugs.Additionally,echinocandins resistance has emerged in Candida albicans,Candida glabrata,Candida tropicalis,and Candida parapsilosis.
		                        		
		                        		
		                        		
		                        	
5.Detection of Neoehrlichia mikurensis in rodents on the basis of the groEL gene in Yunnan commensal rodent plague foci
Rong WEI ; Zi-Wei LI ; Yun-Yan LUO ; Na WANG ; Shu-Qing LIU ; Jin-Chun LI ; Jiang-Li LU ; Jia-Xiang YIN
Chinese Journal of Zoonoses 2024;40(7):689-695
		                        		
		                        			
		                        			The purpose of this study was to understand the prevalence of Neoehrlichia mikurensis in rodents in Yunnan commensal rodent plague foci.Lianghe Country,Mangshi City,and Mile City in Yunnan Province were chosen as sampling sites,where rodents were captured with dead-traps.The N.mikurensis groEL gene in rodent spleen samples was detected with nested PCR,and the positive products were sequenced with Sanger bidirectional assays.The infection rate of N.mikurensis a-mong plague foci,habitats,species,and sexes was compared with Chi-square tests or Fisher's exact probability method.Of 656 rodent spleen samples,12 N.mikurensis positive samples were detected in R.tanezumi,R.sladeni,N.confucianus,and B.bowersi.The positivity rate was 1.83%.No significant difference in the N.mikurensis positivity rate was observed a-mong plague foci,habitats,species,and sexes(P>0.05).Genetic evolution analysis of the groEL gene indicated that the se-quence similarity of nucleic acid sequences in 12 positive samples was 99.5%-100%,and the nucleic acid sequences of N.mikurensis were in the same branch,belonging to cluster Ⅳ.Thus,four species of rodents were found to have low frequency infection with N.mikurensis in Yunnan commensal rodent plague foci.
		                        		
		                        		
		                        		
		                        	
6.A multicenter study of neonatal stroke in Shenzhen,China
Li-Xiu SHI ; Jin-Xing FENG ; Yan-Fang WEI ; Xin-Ru LU ; Yu-Xi ZHANG ; Lin-Ying YANG ; Sheng-Nan HE ; Pei-Juan CHEN ; Jing HAN ; Cheng CHEN ; Hui-Ying TU ; Zhang-Bin YU ; Jin-Jie HUANG ; Shu-Juan ZENG ; Wan-Ling CHEN ; Ying LIU ; Yan-Ping GUO ; Jiao-Yu MAO ; Xiao-Dong LI ; Qian-Shen ZHANG ; Zhi-Li XIE ; Mei-Ying HUANG ; Kun-Shan YAN ; Er-Ya YING ; Jun CHEN ; Yan-Rong WANG ; Ya-Ping LIU ; Bo SONG ; Hua-Yan LIU ; Xiao-Dong XIAO ; Hong TANG ; Yu-Na WANG ; Yin-Sha CAI ; Qi LONG ; Han-Qiang XU ; Hui-Zhan WANG ; Qian SUN ; Fang HAN ; Rui-Biao ZHANG ; Chuan-Zhong YANG ; Lei DOU ; Hui-Ju SHI ; Rui WANG ; Ping JIANG ; Shenzhen Neonatal Data Network
Chinese Journal of Contemporary Pediatrics 2024;26(5):450-455
		                        		
		                        			
		                        			Objective To investigate the incidence rate,clinical characteristics,and prognosis of neonatal stroke in Shenzhen,China.Methods Led by Shenzhen Children's Hospital,the Shenzhen Neonatal Data Collaboration Network organized 21 institutions to collect 36 cases of neonatal stroke from January 2020 to December 2022.The incidence,clinical characteristics,treatment,and prognosis of neonatal stroke in Shenzhen were analyzed.Results The incidence rate of neonatal stroke in 21 hospitals from 2020 to 2022 was 1/15 137,1/6 060,and 1/7 704,respectively.Ischemic stroke accounted for 75%(27/36);boys accounted for 64%(23/36).Among the 36 neonates,31(86%)had disease onset within 3 days after birth,and 19(53%)had convulsion as the initial presentation.Cerebral MRI showed that 22 neonates(61%)had left cerebral infarction and 13(36%)had basal ganglia infarction.Magnetic resonance angiography was performed for 12 neonates,among whom 9(75%)had involvement of the middle cerebral artery.Electroencephalography was performed for 29 neonates,with sharp waves in 21 neonates(72%)and seizures in 10 neonates(34%).Symptomatic/supportive treatment varied across different hospitals.Neonatal Behavioral Neurological Assessment was performed for 12 neonates(33%,12/36),with a mean score of(32±4)points.The prognosis of 27 neonates was followed up to around 12 months of age,with 44%(12/27)of the neonates having a good prognosis.Conclusions Ischemic stroke is the main type of neonatal stroke,often with convulsions as the initial presentation,involvement of the middle cerebral artery,sharp waves on electroencephalography,and a relatively low neurodevelopment score.Symptomatic/supportive treatment is the main treatment method,and some neonates tend to have a poor prognosis.
		                        		
		                        		
		                        		
		                        	
7.Clinical trial of insulin degludec and insulin aspart and insulin aspart 30 in non-obese patients with type 2 diatetes meuitus
Zhen LIU ; Hai-Lan ZHENG ; Lan JIANG ; Wei DING ; Rong WANG ; Na JIN
The Chinese Journal of Clinical Pharmacology 2024;40(12):1714-1717
		                        		
		                        			
		                        			Objective To compare the blood glucose control effect and safety between insulin degludec and insulin aspart and insulin aspart 30 in non-obese patients with type 2 diabetes mellitus(T2DM).Methods Non-obese patients with T2DM were divided into treatment group and control group according to different treatment methods.The control group was treated with insulin aspart 30,and the treatment group was treated with insulin degludec and insulin aspart.Pancreatic islet related indicators[fasting C-peptide(FCP)and 2-hour postprandial C-peptide(2 h CP)],blood glucose control effect[fasting blood glucose(FBG),2-hour postprandial blood glucose(2 h PG)and glycated hemoglobin(HbA1c)],serum 25-hydroxyvitamin D[25(OH)D]and the risk of hypoglycemia were compared between the two groups.Results There were 41 cases in treatment group and 39 cases in control group.After treatment,FCP levels in treatment group and control group were(0.84±0.09)and(1.07±0.14)nmol·L-1;2 h CP levels were(1.03±0.15)and(1.69±0.17)nmol·L-1;FBG levels were(5.46±0.57)and(6.18±0.67)mmol·L-1;2 h PG levels were(8.17±0.85)and(9.03±0.94)mmol·L-1;HbA1 c were(5.35±0.57)%and(6.47±0.68)%;25(OH)D levels were(26.33±2.75)and(20.54±2.17)nmol·L-1,all with significant difference(all P<0.05).The incidence rates of non-severe hypoglycemia in treatment group and control group were 14.63%and 35.90%,with statistically significant difference(P<0.05).The incidence rates of severe hypoglycemia in treatment group and control group were 9.76%and 12.82%;the incidence rates of nocturnal hypoglycemia were 19.51%and 17.95%,without statistically significant difference(all P>0.05).Conclusion The overall therapeutic effect of insulin degludec and insulin aspart on non-obese patients with T2DM is better than that of insulin aspart 30.The former can effectively regulate blood glucose and pancreatic islet cell function,lower the risk of non-severe hypoglycemia.
		                        		
		                        		
		                        		
		                        	
8.Bioequivalence study of olmesartan medoxomil tablet in Chinese healthy subjects
Na SHAN ; Da-Hai JIANG ; Lin-Lin MIAO ; Zhen-Li REN ; Peng-Bo JIN ; Pei-Qi HAO ; Li AN ; Hong ZHU ; Yong XIN ; Guang-De YANG ; Feng LIU
The Chinese Journal of Clinical Pharmacology 2024;40(20):3033-3037
		                        		
		                        			
		                        			Objective To study the bioequivalence of test and reference olmesartan tablet in Chinese healthy subjects after single dose under fasting and fed conditions.Methods A single-center,random,open,single-dose,two-preparations,double-period,crossover study was adopted.A total of 48 healthy adult male and female subjects(24 cases of fasting test and 24 cases of fed test)were included in the random crossover administration.Single oral dose 20 mg of test and reference were taken under fasting and postprandial conditions,respectively.Plasma concentration of olmesartan in plasma were determined by liquid chromatography tandem mass spectrometry.The main pharmacokinetic parameters were calculated by Phoenix WinNonlin 8.0 software.Results The main pharmacokinetic parameters of the test and reference preparations of olmesartan tablets in the fasting group were as follows:Cmax were(653.06±133.53)and(617.37±151.16)ng·mL-1,AUC0-t were(4 201.18±1 035.21)and(4 087.38±889.99)ng·mL-1·h,AUC0-∞ were(4 254.30±1 058.90)and(4 135.69±905.29)ng·mL-1·h.The main pharmacokinetic parameters of the test and reference preparations of olmesartan tablets in the postprandial group were as follows:Cmax were(574.78±177.05)and(579.98±107.74)ng·mL-1,AUC0-t were(3 288.37±866.06)and(3 181.51±801.06)ng·mL-1·h,AUC0-∞ were(3 326.11±874.26)and(3 242.01±823.09)ng·mL-1·h.Under fasting and postprandial conditions,the 90%confidence intervals of the main pharmacokinetic parameters of the test and reference preparations are both 80.00%-125.00%.Conclusion Under fasting and postprandial conditions,a single oral dose of test and reference preparations olmesartan tablets in Chinese healthy adult volunteers showed bioequivalence.
		                        		
		                        		
		                        		
		                        	
9.Value of 18F-FDG PET/CT combined with tumor markers ProGRP and NSE in diagnosis and differential diagnosis of stageⅠA small cell lung cancer
Shuai LIN ; Na FANG ; Wenwen JIANG ; Chaowei LI ; Fei JIN ; Cuiyu LIU ; Lei ZENG ; Jing ZHANG ; Yanli WANG
Chinese Journal of Nuclear Medicine and Molecular Imaging 2023;43(6):355-359
		                        		
		                        			
		                        			Objective:To explore the value of 18F-FDG PET/CT combined with pro-gastrin-releasing peptide (ProGRP) and neuron-specific enolase (NSE) in diagnosis and differential diagnosis of stageⅠA small cell lung cancer (SCLC). Methods:From June 2017 to October 2021, 113 patients (75 males, 38 females; age 32-79 years) with stageⅠA lung cancer (70 with adenocarcinoma, 25 with squamous cell carcinoma, 18 with SCLC; patients with adenocarcinoma and squamous cell carcinoma were combined into non-SCLC (NSCLC) group) and 30 patients with benign pulmonary nodule (21 males, 9 females; age 37-77 years) from the Affiliated Qingdao Central Hospital of Qingdao University were retrospectively analyzed. All patients were examined by 18F-FDG PET/CT and serum tumor markers associated with lung cancer. Differences of the clinical, imaging and tumor markers data among different groups were analyzed by χ2 test, Fisher exact test and Kruskal-Wallis rank sum test. Independent risk factors were analyzed by logistic regression analysis and ROC curve analysis was used to analyze the value of different predictive factors in diagnosis and differential diagnosis of SCLC. Results:There were significant differences in SUV max, lobulation sign, spiculation sign, calcification, pleural traction sign, ProGRP, NSE and carcinoembryonic antigen (CEA) among SCLC, NSCLC and benign nodules groups ( H values: 14.06-20.54, χ2 values: 8.16-14.95, all P<0.05), in which lobulation sign of SCLC was more than that of benign nodules (12/18 vs 26.7%(8/30); χ2=7.41, P=0.007), spiculation sign (2/18 vs 51.6%(49/95); χ2=10.01, P=0.002) and pleural traction sign (1/18 vs 35.8%(34/95); χ2=6.47, P=0.011) were less than those of NSCLC, SUV max was higher than that of benign nodules (7.4(5.8, 9.0) vs 2.3(1.4, 5.1); H=51.82, P<0.001), ProGRP was higher than that of NSCLC and benign nodules (64.0(40.1, 84.8) vs 38.7(26.9, 47.6), 36.7(29.1, 40.5) ng/L; H values: 36.13, 43.96, P values: 0.002, 0.001) and NSE was higher than that of benign nodules (12.4(10.9, 14.5) vs 7.4(5.4, 11.8) μg/L; H=40.53, P=0.001). When differentiated SCLC from NSCLC, spiculation sign (odds ratio ( OR)=0.043, 95% CI: 0.004-0.450, P=0.009) and ProGRP ( OR=1.083, 95% CI: 1.035-1.133, P<0.001) were independent risk factors for SCLC, and the AUC of the two factors combination was 0.875, with the sensitivity and specificity of 14/18 and 84.2%(80/95). When differentiated SCLC from benign nodules, SUV max( OR=2.706, 95% CI: 1.099-6.662, P=0.030), ProGRP ( OR=1.165, 95% CI: 1.009-1.344, P=0.038) and NSE ( OR=1.639, 95% CI: 1.016-2.645, P=0.043) were independent risk factors for SCLC, and the AUC of the three factors combination was 0.985, with the sensitivity and specificity of 17/18 and 96.7%(29/30). Conclusion:18F-FDG PET/CT combined with tumor markers ProGRP and NSE is helpful to improve the diagnosis and differential diagnosis of stage ⅠA SCLC.
		                        		
		                        		
		                        		
		                        	
10.The effect of sonic activated device used for different time on intracanal smear layer removal: An SEM analysis
Min XIAO ; Jin LIU ; Xiaomin FAN ; Haoze WU ; Jueyu WANG ; Kejing WANG ; Na LI ; Wenkai JIANG ; Xiaohan MEI
STOMATOLOGY 2023;43(1):46-51
		                        		
		                        			Objective :
		                        			To observe the clearance of smear layer on the root canal wall in different action time by scanning electron microscope (SEM), and to determine the optimal amount of time using sonically activated irrigation to wash root canal in clinic. 
		                        		
		                        			Methods:
		                        			 Fifty-six ex vivo human anterior teeth with single straight root canal were selected. After routine mechanical preparation, they were divided into two experimental groups according to different irrigating agents: saline group and EDTA group. Each group was assisted by VDW sonic activation EDDY. The saline group was divided into three subgroups according to the irrigating time: 5 s, 30 s and 50 s; EDTA group was divided into six subgroups according to the irrigating time: 5 s, 10 s, 20 s, 30 s, 40 s and 50 s. The control group did not undergo root canal irrigation. After irrigation, the root was cut longitudinally. The smear layer of crown, middle and apical of root canal wall was observed by SEM.
		                        		
		                        			 Results:
		                        			 After irrigating for 30 seconds, there was a significant difference between the normal saline group and the control group and the 5 second group (P<0.05), and there was no difference in the middle and apical part (P>0.05). After 50 seconds, there was a significant difference in the score of the smear layer between the apical area and the other groups (P<0.05). After irrigating for 5 seconds or 10 seconds in EDTA group, there was a significant difference between the scores of the crown and middle area of the root canal and the control group (P<0.05), and there was no significant difference in the apical area (P>0.05). There was a significant difference between the 20-40 second group and the first two groups (P<0.05). There was a significant difference between the 50 second group and the other groups (P<0.05). Comparing the cleaning effect on the smear layer after 50 seconds of irrigating between the two experimental groups, the whole root canal showed significant statistical difference (P<0.05). 
		                        		
		                        			Conclusion 
		                        			The EDTA-assisted sonic activated device used for 50 seconds has the best cleaning effect.
		                        		
		                        		
		                        		
		                        	
            
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