首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 46 毫秒
1.
Objective: To observe the accuracy of femoral preparation and the position of the cementless prosthesis in femoral cavity, and to compare the results between the computer-assisted surgical group (CASPAR) and the conventional group. Methods: Ten femoral components were implanted either manually or by CASPAR in cadaver femurs. The specimens were cut to 3 mm thick slices. Microradiograms of every slice were sent to a computer for analysis with special software (IDL). The gaps and the medullary cavities between component and bone, the direct bone contact area of the implant surface, the gap width and the percentage of gap and bone contact area were measured in every slice. Results: In the proximal implant coated with HA of the CASPAR group, the average percentage of bone contact reached 93.2% (ranging from 87.6% to 99.7%); the average gap percentage was 2.9% (ranging from 0.3% to 7.8%); the maximum gap width was 0.81 mm and the average gap width was only 0.20 mm. While in the conventional group, the average  相似文献   

2.
研究目的：创新要点：研究方法：重要结论：观察人类上颌中切牙拔除后牙槽骨外形改建的规律。锥形束计算机断层摄影（CBCT）在口腔硬组织测量方面具有可靠性,在不同时期拍摄的影像中测量具有可重复性。本研究充分利用这一影像学工具观察人类上颌中切牙拔除后牙槽骨改建的规律。选择40名患者上颌中切牙拔牙前和拔牙后三个月时拍摄的两份CBCT影像资料。在第一次CBCT中,选取中切牙拔牙窝深、中、浅三个水平断层进行矢状断层重建,分别记录矢状断层起点到拟拔除中切牙（实验牙T）牙髓中心移动的层数,并测量实验牙T处牙槽骨宽度,在中切牙拔牙窝中层测量腭平面相关垂直距离。在第二次CBCT的三个水平断层上,依据第一次记录的移动层数定位实验牙T,并在定位处测量牙槽骨宽度。在中切牙拔牙窝中层上转移第一次CBCT记录的腭平面相关距离,并测量唇腭侧牙槽嵴顶沿原牙根外形垂直吸收的距离。上颌中切牙拔除后三个月,在拔牙窝的不同深度,唇侧的牙槽骨均有不同程度的水平骨吸收,越接近牙槽嵴项处牙槽骨吸收越明显。唇腭侧牙槽嵴顶均有明显的垂直骨吸收,唇侧牙槽嵴项的垂直骨吸收比腭侧明显。  相似文献   

3.
研究目的：探讨同一患者不同时期所拍的锥形束计算机断层摄影（CBCT）是否因每次拍摄时投照角度不可能完全一致而影响数据测量的准确性。创新要点：提出了一种人类后牙拔除后观察牙槽突外形变化的准确、无创、科学的定位方法。研究方法：选择首都医科大学附属北京口腔医院种植中心60名患者两份于上颌后牙种植前后拍摄的CBCT影像资料。以磨牙根分叉区三个牙根开始分开处（图像上显示为三根恰好融合的点）为基准点定位两次CBCT的起始水平断层。在第一次CBCT的起始水平断层上,连线牙列远端磨牙参照点即矢状断层起点与近端双尖牙的髓室中心进行矢状断层重建。若实验牙为第一磨牙,找到通过其腭根髓室中心的矢状断层;若实验牙为第二双尖牙,找到通过其髓室中心的矢状断层。记录由矢状断层起点到实验牙移动的层数N,在水平断层上测量实验牙牙槽骨宽度,在实验牙髓室中心的矢状断层上测量牙全长。在第二次CBCT中依据第一次记录的移动层数N定位矢状断层,在定位后的矢状断层上测量实验牙全长,在水平断层的相应定位处测量牙槽骨宽度。重要结论：利用本研究提出的定位方法可以精准定位同一患者不同CBCT影像资料中的同一断层,从而实现拔牙位点动态连续观察。  相似文献   

4.
The purpose of this study was to analyze the effect of strontium-substituted hydroxyapatite (Sr-HA) on bone osseointegration of the implants using fluorescence microscopy. We allocated 20 implants to two groups: Sr-HA group and HA group. Electrochemically deposited HA and Sr-HA coatings were applied onto the implants separately. All the implants were inserted into femur bone of rabbits. Oxytetracycline hydrochloride, alizarin-complexon, and calcein green were respectively administered 7, 28, and 46 d after the implantation. After eight weeks, femurs were retrieved and prepared for the fluorescence microscopy observation. We analyzed the bone mineral apposition rates (MARs), bone area ratios (BARs), and bone to implant contact (BIC) of the two groups. Fluorescence microscopic observation showed that all groups exhibited extensive early peri-implant bone formation. The MAR of the Sr-HA group was greater than that for pure HA from 7 to 28 d after implantation, but no significant difference was found at later stage. And the BIC showed difference at 7 and 28 d compared with pure HA. We concluded that Sr-HA coating can improve the bone osseointegration of the implant in the early stage compared with the HA coating.  相似文献   

5.
微生物发酵床对育肥猪生产性能及猪肉品质的影响   总被引：2，自引：0，他引：2  
为研究发酵床养猪对猪肉品质的影响,试验选择28d断奶的杜长大三元杂交仔猪60头,随机分成试验组和对照组,试验组以发酵床饲养,对照组采用常规水泥地面饲养,试验期为125d,试验结束时,每组随机抽样6头猪进行屠宰测定。试验结果:与对照组相比,试验猪日增重和饲料转化效率分别提高了8.49%和6.27%,背膘厚降低6.8%,脂率降低5.37%,腿臀比例增加6.98%,差异均为显著(P<0.05),而眼肌面积,瘦肉率,屠宰率、板油率、骨率及皮率等指标无明显差异(P>0.05),在肉品质方面,试验组猪肉的颜色、pH值、失水率、滴水损失、熟肉率等肉品质指标均有明显的改善(P<0.05)。表明了相对于水泥面饲养,发酵床养猪有明显提高猪的生长性能和猪肉品质的作用。  相似文献   

6.
Vaginal introital diameter in the evaluation of sexual abuse   总被引：3，自引：0，他引：3  
Physical objective markers to aid in the diagnosis of sexual abuse are few. We therefore studied 242 females, ages 1 through 12 years, to determine if the vaginal introital diameter is useful in evaluating a child for sexual abuse. The children were divided into three groups: Group I, history of sexual contact and/or Neisseria gonorrhoeae; Group II, no history of sexual contact but at risk; and Group III, nonabused. A vaginal introital transverse diameter of greater than 4 mm was more prevalent among children in Group I (94%) than in Group II, (5%); or in Group III (0%) (chi 2, p less than .001). Eighty-eight percent of children who complained of penile-vaginal penetration had a vaginal introital diameter greater than 4 mm as compared to 18% of children with no penetration (chi 2, p less than .001). Forty-six percent of children who complained of fondling with penetration had a vaginal introital diameter of greater than 4 mm as compared to 14% in those without a history of penetration (chi 2, p less than .008). Fifty-eight percent of children with more than one encounter had a vaginal introital diameter greater than 4 mm as compared to 29% in those with one encounter (chi 2, p less than .006). In a logarithmic regression analysis, the greatest proportion of children with a vaginal introital diameter greater than 4 mm was observed in the penile-vaginal contact group (chi 2, p less than .00003). The test is not very sensitive but highly specific. The sensitivity drops precipitously at greater than 5 mm without losing the specificity. A vaginal introital diameter of greater than 4 mm is highly associated with sexual contact in children less than 13 years of age.  相似文献   

7.
目的研究三明治法Onlay植骨结合GBR技术应用于上颌骨洞穿性骨缺损后牙槽嵴水平向及垂直向骨量的变化;评价该项技术在口腔种植中的应用效果。方法抽取泰州市中医院近年的5名病例作为研究对象,通过口腔专科检查和口腔颌面CT检查进行术前评估,通过Onlay植骨结合GBR技术修复骨缺损区,恢复缺牙区的骨量和缺失牙,手术后8个月通过CT检查,评估骨增量效果,并行种植修复。结果植骨术后8个月,患者缺牙区牙槽嵴水平骨量提升4.2mm,垂直骨量提升18mm,患者口腔软组织、牙龈颜色、牙龈乳头均基本恢复正常,供骨区无神经症状、继发性感染及其他不适。种植体骨结合良好,稳定性佳,患者对修复效果满意。种植牙留存率100%。结论三明治法Onlay自体骨移植结合GBR技术是解决上颌骨洞穿性骨缺损的有效临床途径,能够使牙槽骨水平向及垂直向骨量均得到良好改善,为后期的种植修复提供良好的骨基础。  相似文献   

8.
为优化投射式电容织物触摸垫结构,以得到优异的触控性能,针对条形电极形式,以触摸前后电容的相对变化率表示触控信号,运用仿真和实验验证相结合的方法研究不同电极宽度与不同电极间间隙对投射式电容织物触摸垫初始电容及分布的影响。结果表明,电极宽度和电极间间隙的增加使触摸垫驱动电极和感应电极间的初始电容增加,但电极宽度影响更为显著,并且触摸垫电极间的互电容呈边缘小中间大的分布状态。在电极导电率为61.6×106S/m,电极宽度约为2mm~3mm,电极间间隙在3mm左右情况下实验,结果显示,触摸垫在触摸前后的电容变化率较大,触控信号较强。  相似文献   

9.
Objective: To demonstrate the validity and reliability of volumetric quantitative computed tomography (vQCT) with multi-slice computed tomography (MSCT) and dual energy X-ray absorptiometry (DXA) for hip bone mineral density (BMD) measurements, and to compare the differences between the two techniques in discriminating postmenopausal women with osteoporosis-related vertebral fractures from those without. Methods: Ninety subjects were enrolled and divided into three groups based on the BMD values of the lumbar spine and/or the femoral neck by DXA. Groups 1 and 2 consisted of postmenopausal women with BMD changes ＜-2SD, with and without radiographically confirmed vertebral fracture (n=11 and 33, respectively).Group 3 comprised normal controls with BMD changes ≥-1SD (n=46). Post-MSCT (GE, LightSpeed16) scan reconstructed images of the abdominal-pelvic region, 1.25 mm thick per slice, were processed by OsteoCAD software to calculate the following parameters: volumetric BMD values of trabecular bone (TRAB), cortical bone (CORT), and integral bone (INTGL) of the left femoral neck, femoral neck axis length (NAL), and minimum cross-section area (mCSA). DXA BMD measurements of the lumbar spine (AP-SPINE) and the left femoral neck (NECK) also were performed for each subject. Results: The values of all seven parameters were significantly lower in subjects of Groups 1 and 2 than in normal postmenopausal women (P＜0.05, respectively).Comparing Groups 1 and 2, 3D-TRAB and 3D-INTGL were significantly lower in postmenopausal women with vertebral fracture(s) [(109.8±9.61) and (243.3±33.0) mg/cm3, respectively] than in those without [(148.9±7.47) and (285.4±17.8) mg/cm3,respectively] (P＜0.05, respectively), but no significant differences were evident in AP-SPINE or NECK BMD. Conclusion: the femoral neck-derived volumetric BMD parameters using vQCT appeared better than the DXA-derived ones in discriminating osteoporotic postmenopausal women with vertebral fractures from those without, vQCT might be useful to evaluate the effect of osteoporotic vertebral fracture status on changes in bone mass in the femoral neck.  相似文献   

10.
目的：分析和评价加长柄人工股骨头置换术治疗高龄股骨粗隆部不稳定骨折的方法及疗效。方法：本组15例,男10例,女5例;年龄70～90}0,平均79岁。骨折按Evans分类,ⅢA型9例,ⅢB型6例。取髋关节后外侧切口,术中注意保留股骨大、小转子部位的骨折块,用骨水泥固定,争取将其重新复位。由于股骨颈及股骨距骨缺损,在插入人工股骨柄之前可用试模测试。股骨距部位的骨缺损用骨水泥充填重塑,关节腔内置负压引流管48—72h。结果：15例患者均康复出院。住院时间16～24d,平均20d。均获得随访,平均随访时间8个月（6—12个月）,伤口均一期愈合,无感染,无假体松动,无下肢深静脉栓塞发生,无髋关节脱位或半脱位发生,无病人死于手术并发症,12例病人髋关节功能满意。结论：加长柄人工股骨头置换术是治疗高龄股骨粗隆部不稳定骨折的可靠方法,其操作可行,疗效满意,可降低死亡率、改善生活质量。  相似文献   

11.
[目的]利用微核试验研究CpGODN的遗传毒性.[方法]分别以10μg/只、100μg/只、300μg/只3个不同剂量CpGODN0.1ml腹腔注射染毒健康昆明小鼠,24h后以同样剂量再次注射染毒,6h后脱颈处死动物,制片,观察并计数嗜多染红细胞微核试验,进行统计分析.[结果]CpGODN在各实验组的小鼠骨髓嗜多染红细胞微核率与盐水阴性对照组比较差异无显著性意义(P>0.05),与环磷酰胺阳性对照组相比具有极显著差异(P<0.01).[结论]所选用CpGODN在受试剂量下不能诱发小鼠股骨骨髓微核的增加,说明微核试验阴性.  相似文献   

12.
Using data from yearbooks for 193 high schools, this study examines the degree of interracial contact in 8,849 high school teams and other organizations. More than one-third of these groups were all-white, while only about 3% were exclusively nonwhite. Owing in large part to their overall numerical preponderance, white students rarely found themselves outnumbered in groups by as much as three to one; by contrast, nonwhites often were in this position. Tabulations show that the degree of interracial exposure was typically less than what would occur if all organizations in each school had been racially balanced and was much less than the exposure that would have occurred if all organizations reflected the racial composition of the schools containing them. Whereas the nonwhite percentage of the students enrolled in the sample high schools was 24.9%, the membership of clubs and teams was 20.7%, reflecting a lower rate of participation by nonwhites. Furthermore, because the racial compositions of clubs and teams were not uniform, the average white member was in an organization that was only 15.3% nonwhite. Although clearly less than its theoretical maximum, this rate of contact nonetheless appears to be much higher than what would occur if friendships were the only vehicle for interracial contact outside the classroom. Finally, the extent of segregation associated with these organizations was the same or less in the South than in the rest of the country.  相似文献   

13.
Objective:The purpose of this study was to investigate the effects of a zinc-substituted nano-hydroxyapatite(Zn-HA) coating,applied by an electrochemical process,on implant osseointegraton in a rabbit model.Methods:A Zn-HA coating or an HA coating was deposited using an electrochemical process.Surface morphology was examined using field-emission scanning electron microscopy.The crystal structure and chemical composition of the coatings were examined using an X-ray diffractometer(XRD) and Fourier transform infrared spectroscopy(FTIR).A total of 78 implants were inserted into femurs and tibias of rabbits.After two,four,and eight weeks,femurs and tibias were retrieved and prepared for histomorphometric evaluation and removal torque(RTQ) tests.Results:Rod-like HA crystals appeared on both implant surfaces.The dimensions of the Zn-HA crystals seemed to be smaller than those of HA.XRD patterns showed that the peaks of both coatings matched well with standard HA patterns.FTIR spectra showed that both coatings consisted of HA crystals.The Zn-HA coating significantly improved the bone area within all threads after four and eight weeks(P<0.05),the bone to implant contact(BIC) at four weeks(P<0.05),and RTQ values after four and eight weeks(P<0.05).Conclusions:The study showed that an electrochemically deposited Zn-HA coating has potential for improving bone integration with an implant surface.  相似文献   

14.
While education levels of women have increased dramatically relative to men, women are still greatly underrepresented in Science, Technology, Engineering, and Mathematics (STEM) college programmes. We use unique data on preference rankings for all secondary school students who apply for college in Ireland and detailed information on school subjects and grades to decompose the sources of the gender gap in STEM. We find that, of the 22 percentage points raw gap, about 13 percentage points is explained by differential subject choices and grades in secondary school. Subject choices are more important than grades – we estimate male comparative advantage in STEM (as measured by subject grades) explains about 3 percentage points of the gender gap. Additionally, differences in overall achievement between girls and boys have a negligible effect. Strikingly, there remains a gender gap of 9 percentage points even for persons who have identical preparation at the end of secondary schooling (in terms of both subjects studied and grades achieved); however, this gap is only 4 percentage points for STEM-ready students. We find that gender gaps are smaller among high-achieving students and for students who go to school in more affluent areas. There is no gender gap in science (the large gaps are in engineering and technology), and we also find a smaller gender gap when we include nursing degrees in STEM, showing that the definition of STEM used is an important determinant of the conclusions reached.  相似文献   

15.
Objective： To introduce the clinical effect among patients who received an unwrapped orbital implant with high density porous polyethylene material （Medpor） after enucleation or evisceration. Methods： Retrospective analysis of a series of 302 patients with anophthalmia who underwent placement of an unwrapped high density porous polyethylene orbital implant. We compared the patients （n=180） who accepted primary implant placement with those （n=122） who accepted secondary implant placement. Parameters evaluated included： age at time of surgery, date of surgery, sex, implant type and size, surgery type, the surgical procedure and technique performed, and complications. Results： The time of follow-up ranged from 2.0 to 58.0 months （mean 32.5 months）. A total of 5 of 302 （1.66%） cases had documented postoperative complications. The following problems were noted after surgery： implant exposure, 3 patients （0.99%）; implant removed due to orbital infection, 1 patient （0.34%）; ptosis, 1 patient （0.34%）. There were no significant complications＇observed in other 297 cases and all implants showed good orbital motility. The clinical effect of primary implant placement is better than that of secondary placement. Conclusion： High density porous polyethylene material can be used successfully as an unwrapped orbital implant in anopthalmic socket surgery with minimal complications. The material is well tolerated, nonantigenic and has low rate of infection and migration.  相似文献   

16.
Objective： The aim of this retrospective investigation was to explore the influence of femoral osteoporosis on short-term curative effects ofcementless hip arthroplasty and to evaluate the femoral metaphyseal bone mineral density （BMD） for femoral osteoporosis in order to guide prosthesis choice and rehabilitation. Methods： We performed 127 total arthroplasty operations between June 1999 to February 2003 and investigated 49 cementless hip replacements with the Metalcancellous cementless Lubeck Ⅱ system being used in all hips. There were twenty men and twenty-nine women whose mean age at the time of the operation was 60 years （range, 52-81 years）. The patients were divided into osteoporosis or normal groups according to the femoral metaphyseal BMD measured preoperatively. The average duration of follow-up was 30 months （range, 8-52 months）. We evaluated all of the patients from a clinical standpoint with use of a standard-terminology questionnaire with respect to the short-term curative effects and patients＇ satisfaction. Hip pain status and functional ability were important indicators of treatment efficacy. Results： Harris hip score and patients＇ satisfaction in femoral osteoporosis patients who underwent noncemented hip arthroplasty were lower （P=0.004, P=0.03） while the incidence of thigh pain was higher （P=0.03） than the patients with non-osteoporosis. Conclusion： The higher incidence of pain, as well as the decrease in function experienced by the patients in osteoporosis group, supports the case that cementless arthroplasty is not a better choice for those patients and that we had better select prosthesis based on the femoral metaphyseal BMD.  相似文献   

17.
探讨配戴渐进多焦点眼镜对青少年近视进展的临床疗效及影响。对2015年6月至2016年6月到贵州医科大学就诊的青少年近视眼患者76例为研究对象,随机分为两组,每组38例,观察组患者配戴渐进多焦点眼镜,对照组配戴常规单焦点框架眼镜治疗。对两组患者配戴1年前后的舒适度、眼镜屈光度、眼轴长度以及临床疗效进行对比。结果渐进多焦点眼镜组患者的舒适度较单焦点眼镜组好,且渐进多焦点眼镜组患者的屈光度低于单焦点眼镜组[(4.20±0.42)D VS(4.62±0.43)D],眼轴长度短于单焦点眼镜组[(24.5±3.1)mm VS(25.1±4.2)mm],两组在平均屈光度与眼轴长度的比较差异显著,具有统计学意义,P<0.05;针对青少年患者近视临床有效率渐进多焦点眼镜组高于单焦点组(92.1%VS 71.0%),差异有统计学意义,P<0.05。渐进多焦点眼镜对于青少年近视患者有较好的舒适度,可以改善患者的近视度数,且对患者的临床有效率较单焦点框架眼镜组高,值得临床推广应用。  相似文献   

18.
高屈曲人工全膝关节表面置换术临床研究   总被引：1，自引：0，他引：1  
目的:探讨应用高屈曲型假体行人工全膝关节置换术的早期临床效果。方法:2002.12~2006.3月间,对125例(213膝)患者用LPS-FLEX高屈曲型假体行TKA。其中男36例(62膝),女89例(151膝),年龄51~85岁,平均68.1岁。骨性关节炎90例(149膝),类风湿性关节炎35例(64膝)。所有病人均行常规髌骨置换,假体均采用骨水泥固定。结果:术后第一天即开始康复训练,伤口均一期愈合。随访12~52个月,平均34个月。2例因早期屈曲不佳(<90°)于术后6周在连续硬膜外麻醉下行手法松解后获得满意屈曲度,2例发生感染,其余均疗效优良。随访X线片结合临床均无感染、假体松动、假体周围骨折、骨吸收及脱位发生。HSS评分由术前30~65分,平均48分,提高至术后85~98分,平均91分。结论:LPS-FLEX高屈曲型假体在高屈曲位时仍在胫骨上保持面接触,且胫骨CAM始终在股骨SPINE的基部,从而在获得最大屈曲的同时保持了良好的稳定性。  相似文献   

19.
This study was aimed to elucidate whether there is significant relationship between the lower calyceal anatomy and stone evacuation following extracorporeal shock wave lithotripsy(ESWL). From April 1995 to November 1999, 145 patients with lower caliceal stones underwent ESWL with Storz Modulith SL20 lithotriptor. The pelvicalyecal angle, lower pole infundibular length and width, and lower pole calyceal pattern of the stone-bearing calyx were measured on pre-ESWL intravenous urograms. Abdominal plain film and ultrasonography taken of all patients at the 3-month followup showed that the overall stone-free rate was 65% after 3 months. The stone-free rate was significantly correlated to the radiographic anatomical factor, 94% in patients with a pelvicalyceal angle of 90 degrees or greater, 57% in those with less than 90 degrees pelvicalyceal angle; 80% in those with infundibular length of 30 mm or less, 59% in those with infundibular length greater than 30 mm; 73% in those with infundibular width greater than 4 mm, 48% in those with infundibular width of 4 mm or less; 85% in those with a simple calyceal pattern and 41% in those with a complex one. These findings suggest that the 4 radiographic anatomical factors of the lower pole calyx (pelvicalyceal angle, infundibular length and width and calyceal pattern) play an important role in stone evacuation after ESWL. Pelvicalyceal angle of 90 degrees or greater, infundibular length of 30 mm or less and width greater than 4 mm, and simple calyceal pattern are respectively noted to relate to an improved stone-free status. In contrast, an acute pelvicalyceal angle, long infundibular length and narrow infundibular width and complex calyceal pattern are individually unfavorable factors for stone emptying following ESWL.  相似文献   

20.
This paper analyzes changes in the teacher salary schedules of Michigan school districts between 1970 and 1980. We find that starting salaries, expressed in 1970 dollars, decreased by an average of 20% over the decade. Real maximum salaries decreased by 15%. The between-district variability of starting salaries increased markedly over the decade, making the average starting salary a much poorer estimate of the starting salary a particular teacher earned in 1980 than was the case in 1970. The between-district variability of maximum salaries did not increase over the decade. Student enrollment changes were a significant predictor of the changes in maximum salaries. Districts that experienced the greatest percentage losses in students tended to experience the greatest declines in real maximum salaries. Student enrollment changes were also related to changes in starting salaries, but the relationship was more complex.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号