3.Three-dimensional finite element analysis of maxillary anterior teeth retraction force system in light wire technique.
Xiangfeng ZHANG ; Chao WANG ; Xi XIA ; Feng DENG ; Yi ZHANG
West China Journal of Stomatology 2015;33(3):291-295
OBJECTIVEThis study aims to construct a three-dimensional finite element model of a maxillary anterior teeth retraction force system in light wire technique and to investigate the difference of hydrostatic pressure and initial displacement of upper anterior teeth under different torque values of tip back bend.
METHODSA geometric three-dimensional model of the maxillary bone, including all the upper teeth, was achieved via CT scan. To construct the force model system, lingual brackets and wire were constructed by using the Solidworks. Brackets software, and wire were assembled to the teeth. ANASYS was used to calculate the hydrostatic pressure and the initial displacement of maxillary anterior teeth under different tip-back bend moments of 15, 30, 45, 60, and 75 Nmm when the class II elastic force was 0.556 N.
RESULTSHydrostatic pressure was concentrated in the root apices and cervical margin of upper anterior teeth. Distal tipping and relative intrusive displacement were observed. The hydrostatic pressure and initial displacement of upper canine were greater than in the central and lateral incisors. This hydrostatic pressure and initial intrusive displacement increased with an increase in tip-back bend moment.
CONCLUSIONLingual retraction force system of maxillary anterior teeth in light wire technique can be applied safely and controllably. The type and quantity of teeth movement can be controlled by the alteration of tip-back bend moment.
Finite Element Analysis ; Humans ; Incisor ; Maxilla ; Tooth Movement Techniques ; methods ; Tooth Root ; Torque
4.Novel no-flip Shang Ring circumcision for adult males: a clinical application study of 528 cases.
Ben-Hai YANG ; Chao JIA ; Tao LIU ; Yi-Feng PENG
National Journal of Andrology 2014;20(8):709-714
OBJECTIVETo evaluate the safety and clinical outcomes of the novel simplified no-flip surgical approach to Shang Ring male circumcision in adults.
METHODSA total of 528 adult males, aged 18 - 58 (mean 35) years, 63 with phimosis and 465 with redundant prepuce, underwent no-flip Shang Ring circumcision with or without removal of the outer ring. The operation time and intraoperative blood loss were recorded and observations were made on such complications as postoperative bleeding, infection, edema, and wound dehiscence.
RESULTSThe operation time, intraoperative blood loss, and 2-hour postoperative pain score were (3.8 +/- 0.3) min, (0.6 +/- 0.1) ml, and 7.3 +/-0.3, respectively. Spontaneous ring detachment occurred at 21.6 +/- 2.1 days postoperatively in 12.7% of the patients (67/528) who had chosen not to remove the rings. Of those who preferred removal of the outer ring (87.3% [461/528]), none experienced any pain at the ring removal 7 days after the operation. Postoperative complications included infection in 3 cases (0.56%) and mild edema in 9 (1.70%), but no bleeding and wound dehiscence. Totally, 518 (98.1%) of the patients felt satisfied with the postoperative penile appearance.
CONCLUSIONNo-flip Shang Ring circumcision, with no need for removal of the inner ring, is a safe and simple approach for adult males, which is superior to conventional Shang Ring circumcision for requirement of fewer surgical instruments, shorter operation time, lower incidence of complications, and better satisfaction with the penile appearance. However, these advantages are to be further demonstrated by more randomized controlled trials.
Adolescent ; Adult ; Circumcision, Male ; instrumentation ; methods ; Humans ; Male ; Middle Aged ; Phimosis ; surgery ; Postoperative Complications ; Young Adult
5.Analysis on minimum alveolar effective concentration of sevoflurane for laryngeal mask airway insertion under general anesthesia in premature infants
Qiang WANG ; Chao GAO ; Lan YAO ; Lan GAO ; Yi FENG
Chongqing Medicine 2016;45(33):4678-4679,4683
Objective To determine the minimum alveolar concentration(MAC) of sevoflurane without body movement during laryngeal mask airway(LMA)intubation in premature infants less than 37 weeks of corrected gestational age undergoing total inhalation general anesthesia induction.Methods Twenty-one ASA Ⅰ or Ⅱ premature infants less than 37 weeks of corrected gestational age undergoing elective inhalation general anesthesia were enrolled in this study.At first,the general anesthesia induction was started by inhaling 6 % sevoflurane.After the premature infant lost consciousness,the end tidal sevoflurane concentration(ET-sev)was adjusted to the predetermined concentration and maintained stable for 15 min.After that,LMA was inserted.The up-anddown sequential allocation was used to determine MAC.The initial ETsev was 2 %,which was increased or decreased by 1 gradient concentration in the next case according to the LMA insertion body movement response.The adjacent concentration gradient was 0.2%.The midpoint from th body movement response to non-body movement response was set as the balance point and the mean value of the concentrations of sevoflurane at all the balance points were calculated as MAC.Results The end tidal sevoflurane con centration without the body movement responses to LMA insertion was 1.71%.Conclusion The MAC of sevoflurane without the body movement responses to LMA insertion in premature infants less than 37 weeks of corrected gestational age is 1.71%,which is lower than that in the normal children and probably because imperfect central nervous system development in premature infants.
6.Subfascial Endoscopic Communicating Branch Vein Ablati on in Treating Communicating Branch Vein Insufficiency (Report of 57 Cases)
Leping YIN ; Chao FENG ; Yi GU ; Tong LIU
Chinese Journal of Bases and Clinics in General Surgery 2003;0(05):-
Objective To study the effectiveness of subfascial endoscopic communicating branch vein ablation in treating communi cating branch vein insufficiency.Methods Fifty-seven cases of primary lower ext remity vein valve insufficiency complicated by communicating vein insufficiency diagnosed by venography and color duplex were treated with subfascial endoscopic communicating branch vein ablation, and their information was analyzed retrosp ectively.Results Swelling was observed in leg of 7 cases after operation, and disappeared within one week spontaneously. Incision infec tion occurred in 2 cases and skin ambustion happened in 2 cases. Superficial vei n varicosis disappeared in all case, skin pigmentatin declined significantly and ulcers healed in 2-3 weeks.Conclusion Subfascial endoscopic communicating branch vein ablation is an excellent choice in treating communicating branch ve in insufficiency.
7.APOE Genotypes Frequency of Chinese Old People in Rural Area
Feng MA ; Chao-Ke LIANG ; Yi-Bin CHENG ; Al ET ;
Journal of Environment and Health 2007;0(08):-
Objective To know the apolipoprotein E(APOE)genotypes frequency of Chinese old people in the rural area. Methods 2000 Chinese aged 65 years or older from four sites in China were enrolled in this study in 2004-2008.Two sites were from the Sichuan province in southwestern China,and another two sites were from the Shandong province in eastern China.The finger blood samples on filter paper were collected from all the investigated people in the end of the interview.The genotype for apolipoprotein E(gene symbol,APOE)was determined by eluting DNA from a dried blood spot,followed by HhaI digestion of amplified products.Results Through statistical analysis,APOE genotypes frequency of Chinese people aged 65 years or older in the rural area,as for ?/?2,?2/?3,?2/?4,?3/?3,?3/?4,?4/?4,they were 1.1%,13.55%,2.05%,68.80%,13.35% and 1.15% respectively.4 carriers and no 4 carriers were 16.55% and 83.45%.Conclusion The distribution of APOE 4 genotype is more widely in Chinese people aged 65 years or older in the rural area.
8.Not Available.
Chao ying FENG ; Meng HE ; Jun yi LIN ; Yi wen SHEN ; Bei xu LI
Journal of Forensic Medicine 2021;37(5):745-748
9.Comparison of two methods of extrapolating sweep pattern visual evoked potential acuity
Chao, FENG ; Chang-zheng, CHEN ; An-huai, YANG ; Yi-qiao, XING ; Lian-fang, YI
Chinese Journal of Experimental Ophthalmology 2011;29(11):1028-1031
Background Sweep pattern visual evoked potential (SVEP) is an objective method of visual test.There is a clear correlation between SVEP acuity and subjective vision,but they are not identical.Recent studies showed that new regression method can improve the accuracy of SVEP acuity. Objective This trial was to investigate and compare the outcome between amplitude-spatial frequency (A-SP) regression method and amplitudelogVA (A-logVA) regression method in extrapolating the SVEP acuity.Methods SVEP was recorded in 113 eyes of 64 subjects using GT-2000 ( Guo Te,China) with the gratings of 10 different spatial frequency from 0.99 to 12.89 cpd as stimulus.The 1 13 eyes included cataract,glaucoma,corneal disease,optical neuropathy,retinal disease,ocular trauma,refractive error and normal eyes.The correlation were analyzed of SVEP acuity,decimal visual acuity and LogMAR visual acuity.The response were averaged and DFT on the monitor display.SVEP acuity was calculated by extrapolating 0 response amplitude.Results The correlation indices of decimal visual acuity curves obtained by the A-logVA function was 0.663,and that obtained by the A-SP function was 0.705.The positive correlation was seen between subjective decimal visual acuity and A-logVA decimal visual acuity (r =0.540,P< 0.01 ) and between subjective decimal acuity and decimal acuity calculated by the A-SP regression method (r=0.620,P<0.01 ).SVEP decimal acuity calculated by the A-SP function regression method was significantly different from the that calculated by the A-logVA function regression method (Z =-8.688,P<0.01 ).And the correlation indices of LogMAR visual acuity curves obtained by the A-logVA function was 0.733 and that obtained by the A-SP function was 0.715.The positive correlation was found between the subjective LogMAR acuity and that calculated by the A-SP regression method (r=0.700,P< 0.01 ) and between the subjective LogMAR acuity and LogMAR acuity calculated by the A-logVA regression method (r=0.710,P<0.01 ).SVEP LogMAR acuity from A-SP function regression method was significantly different from the LogMAR acuity from A-logVA function regression method (Z=-8.748,P<0.01 ).No significant differences of VA LogMAR were found in gender,eyes,type of disease and age(x2 =2.171,P=0.338;x2 =0.976,P=0.614;x2 =6.032,P=0.420;x2 =14.720,P=0.257 ).Conclusions SVEP can obtain the visual outcome in human.The amplitude-logVA function regression method is more accurate in extrapolating SVEP acuity.
10.Changes of photopic negative response in patients with exudative age-related macular degeneration and proliferative diabetic retinopathy after intravitreal injections of bevacizumab
Changwa MEI ; Changzheng CHEN ; Yiqiao XING ; Chao FENG ; Zengping LIU ; Guoge HAN ; Fei XU ; Lionfang YI
Ophthalmology in China 2009;18(4):243-246
Objective To evaluate the changes of the waveform of the photopic negative response in flash-electroretinogram, visual acuity and central retinal thickness in the treatment of intravitreal injections of bevacizumub. Design Retrospective self-comparative case series. Partidpants 8 subjects (9 eyes) with exudative age-related macular degeneration and 3 subjects (3eyes) with proliferative diabetic retinopathy. Method Evaluation protocol included examinations of the Early Treatment Diabetic Retinopathy study visual acu-ity, visual field, intraocular pressure, fundus fluorescein angiography, optical coherence tomography and flash-electroretinogram. Intravit-real injections of bevacizumab, 1.25 mg (0.05ml), were given under an operating microscope and aseptic conditions. All the subjects were followed-up one month later. Main outcome Measure The amplitudes of PhNR, visual acuity and central retinal thickness. Re-sult At 1 months, the mean amplitudes of PhNR and mean visual acuity in all cases had no obvious change (n=12, P>0.05).The central retinal thickness reduced obviously (n=12, P<0.05), but it was neither significantly correlated with PhNR (r=0.294, P=0.145) nor with visual acuity(r=-0.358, P=0.073). Conclusion The single intravitreal injection of bevacizumab is showed promising in absorption of in-traretinal edema and subretinal fluid in patients with exudative age-related macular degeneration and proliferative diabetic retinopathy, but the changes of visual function (including PhNR) might need further investigation. (Ophthalmol CHN, 2009, 18: 243-246)