1.A in vitro study of coronal microleakage of different post and cement systems
Yunzhi FENG ; Mei CHEN ; Yachong WANG
Journal of Practical Stomatology 2009;25(4):482-485
Objective: To compare the coronal sealing abilities of different post and cement systems through measuring the value of leakage by using dye method. Methods: Fifty human mandibular premolars with single canal were divided into 6 groups randomly. A group: roots sealed by temporary material, B group: roots restored with fiber post adhered with composite resin cement, C group: roots restored with casting metal post and core adhered with composite resin and zinc phosphate cement, D group: positive control, E group: negative control. After finishing preparation and restoration of roots, microleakage was determined by using dye method. Results: The groups restored with any post and core system produced significantly less microleakage than temporary material sealing group(P<0.05). But no differences were detected between two groups bonded with the composite resin cement (P>0.05). Posts adhered with zinc phosphate luting agent produced more leakage than those with composite resin cement(P<0.05). Conclusion: Luting agent can decrease the coronal microleakage. Composite resin cement provides better sealing ability.
2.Research on function of Multi-channel Brain Magnetic Stimulation Machine in auditory memory
Mei XU ; Xuemin WANG ; Feng CHEN
Chinese Medical Equipment Journal 2003;0(12):-
Objective:To check the clinical effect of Multi-channel Brain Magnetic Stimulation Machine.Method:Sixteen volunteers are divided into two groups.Members of the first group which is the corresponding group listen to news material in the sober state and then answer the questionnaire.At last their EEG is collected.Members of the second group listen to the same material in the sober state and they are stimulated at the forehead and temporal area by Multi-channel Brain Magnetic Stimulation Machine at the same time.They also answer the questionnaire under the magnetic stimulation at forehead and their EEG is collected,too.Result:Answers of the second group are obviously better than the first group.The power spectrum of EEG at the forehead,temporal,parietal region and even the whole brain area in the first group is stronger than that of the second.Conclusion:Multi-channel Brain Magnetic Stimulation Machine excites brain in a way and then helps people complete the job better.
3.In vitro fracture resistance of endodontically treated anterior teeth with varying ferrule heights and configurations with glass-fiber post
Yachong WANG ; Yunzhi FENG ; Mei CHEN
Journal of Practical Stomatology 2010;26(1):126-127
The extracted human maxillary central incisors were endodontically treated and restored with glass-fiber post. Then they were randomly divided into four groups and tested. Results showed that groups with ferrule more than 2 mm had higher fracture resistence than others.
4.Relationship between early brain damage in preterm infants detected by magnetic resonance imaging and neurodevelopmental outcome
Mei CHEN ; Shulan LI ; Zijian FENG
Chinese Journal of Perinatal Medicine 2013;(5):278-283
Objective To investigate the relationship between early brain menifestation such as white matter damage and ventriculomegaly detected by magnetic resonance imaging(MRI) and adverse neurodevelopmental outcome in preterm infants.Methods From March 15,2007 to April 12,2011,122 preterm infants accepted MRI examination 8-14 days after birth in Chinese People's Liberation Army 202 Hospital.Totally,115 preterm infants were followed up at 12 months old and mental development index(MDI) and psychomotor development index (PDI) score were measured.MDI<70 was as mental dysfunction,-84 as borderline dysfunction and-114 as normal; PDI<70 was as psychomotor dysfunction,-84 as borderline dysfunction and-114 as normal.The relationship between clinical characteristics of preterm infants,MRI abnormalities and neurodevelopmental outcome were analyzed by analysis of variance,LSD and Kruskal-Wallis H test.Results The 122 premature infants included 69 males and 53 females with the median gestational age of 32 weeks(28-36 weeks)and the median birth weight of 2050 g (1270-3110 g).In 24 premature infants with mentaldysfunction,the average gestational age [(28.7 ± 1.7) weeks],birth weight[(1520.1-44.8) g] and 1 min Apgar score (5.5 ± 0.8) were all lower than those in normal infants [n =59,(33.5 ± 2.2)weeks,(2240.4 ± 47.1) g and 7.1 ± 0.8],while the average mechanical ventilation time was longer [(20.4±5.8) dvs (5.6±2.7) d](t=2.37,2.49,2.13 and 2.44,P<0.05).In 20 premature infants with psychomotor dysfunction,the average gestational age [(27.9 ±± 1.4) weeks],birth weight [(1515.6±43.7) g],1 min Apgar score (5.6t0.5) were lower than those in normal infants [n=62,(33.2±2.4) weeks,(2264.3±42.5) g and 7.2±0.6],while the mechanical ventilation time was longer [(18.2±4.7) dvs (5.3±2.2) d](t=2.28,2.52,2.09 and 2.38,P<0.05).Among thirteen preterm infants with severe white matter damage,eleven and nine developed mental or psychomotor dysfunction respectively.Among eleven preterm infants with moderate and severe ventriculomegaly,seven and six developed mental or psychomotor dysfunction respectively.The more severe the white matter damage and ventriculomegaly,the higher the incidence of mental (H=16.23 and 14.33,P<0.05) and psychomotor dysfuction (H =18.63 and 12.69,P < 0.05).Conclusions White matter damage is common in preterm infants.Prognosis of preterm infants with mental and psychomotor dysfunction is related with the degree of white matter damage and ventriculomegaly.
5.Study on bonding interface and microstructure of different resin composite inlays
Yaming CHEN ; Hailan FENG ; Lei MEI
Journal of Practical Stomatology 1996;0(02):-
Objective:To evaluate the characteristics of bonding interface and microstructure of different resin composite inlays. Methods:Different composite resins and adhesives were used for restoration of extracted molars, the results were evaluated under scanning electron microscope(SEM) and atomic force microscope(AFM).Results:The microstructure feature of Tescera was with higher density when compared with that of other conventional resins,and fewer small holes could be seen in Tescera. AFM pictures showed that Tescera was with a very smooth surface. Indirect composite resin could be combined with resin bonding agent tightly and infiltrated each other. The interface between direct resin inlay material and resin bonding agent was very clear,and no obvious interfiltration could be seen under SEM and AFM. Conclusion:After treatment with water, heat,light and pressure, the physical properties of indirect composite resin is improved effectively, and obvious infiltration can be found in the interface.
7.A case report of myofasciitis.
Mei CHEN ; Fen-Ping LUO ; Zhi-Chun FENG
Chinese Journal of Contemporary Pediatrics 2008;10(1):87-88
8.Peroneal muscular atrophy in a case.
Feng-li YAO ; Mei CHEN ; Fen-ping LUO
Chinese Journal of Pediatrics 2005;43(11):842-842
9.Recurrent ascites as a presenting manifestation of eosinophilic gastroenteritis: a case report.
Mei CHEN ; Li-Li LU ; Zhi-Chun FENG
Chinese Journal of Contemporary Pediatrics 2011;13(3):265-266
Ascites
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etiology
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Child, Preschool
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Enteritis
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complications
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Eosinophilia
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complications
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Female
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Gastritis
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complications
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Humans
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Recurrence
10.Assessment of left ventricular dyssynchrony and its relationship with cardiac function in dilated cardiomyopathy by two-dimensional strain parameters
Dan'e MEI ; Jinling CHEN ; Chuangli FENG ; Zhiyu ZHAO ; Hongning SONG ;
Chinese Journal of Medical Imaging Technology 2017;33(9):1339-1343
Objective To explore value of two-dimensional speckle tracking imaging (2D-STI) strain parameters in assessment of left ventricular (LV) dyssynchrony and its relationship with cardiac function in patients with dilated cardiomyopathy (DCM).Methods Totally 25 patients with DCM and 25 age-matched normal controls were enrolled.The LV time to peak longitudinal strain (Tls) and time to peak circumferential strain (Tcs) were measured by 2D-STI,from which the standard deviations and maximal differences of the Tls in all 18 segments,6 segments at apical 4-chamber,3-chamber and 2 chamber views (Tls-SD,Tls-SD-4,Tls-SD-3,Tls SD-2,Tls dif,Tls-dif-4,Tls-dif-3,Tls-dif-2) were calculated,as same as the standard deviations and maximal differences of Tcs in all 18 segments,6 segments at mitral valve,papillary muscle,apical short-axis views (Tcs-SD,Tcs-SD-M,Tcs-SD-P,Tcs-SD-A,Tcs-dif,Tcs-dif-M,Tcs-dif-P,Tcs-dif-A) were calculated.Results Compared with the control group,the global and segmental strain parameters of the DCM group increased significantly (all P<0.05).Except for Tcs-dif-P and Tcs dif,the residual strain parameters were negatively correlated with LV ejection fraction (all P<0.05).Except for Tcs-dif-M,Tcs dif-P and Tcs-dif,there was a positive correlation between strain parameters and E/e in DCM group (all P <0.05).Conclusion In patients with DCM,LV dyssynchrony exists both in global and regional,which may aggravates the LV function damage.2D-STI strain parameters can objectively evaluate LV dyssynchrony and its relationship with cardiac function in patients with DCM.