共查询到20条相似文献，搜索用时 31 毫秒
1.
Bei LI Yao WANG 《Journal of Zhejiang University. Science. B》2014,15(12):1064-1071
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
2.
Rong-yang Wang Min Han Hong Liu Chun-ling Wang Hong-hong Xian Lei Zhang Shi-jie Zhang Dong-xu Liu 《Journal of Zhejiang University. Science. B》2012,13(11):942-947
To propose a method of establishing the reference mandibular plane (MP), which could be reestablished according to the coordinates of the reference points, and then facilitate the assessment of anterior alveolar morphology using cone beam computed tomography (CBCT), sixty patients with bimaxillary protrusion were randomly selected and CBCT scans were taken. The CBCT scans were transferred to Materialism’s interactive medical image control system 10.01 (MIMICS 10.01), and three dimensional models of the entire jaws were constructed. Reference points determining the reference MP were positioned in the coronal, axial, sagittal windows, and the points were exactly located by recording their coordinates in the interfaces of software. The reference MP provided high intra-observer reliability (Pearson’s r 0.992 to 0.999), and inter-observer reliability (intra-class correlation coefficients (ICCs) 0.996 to 0.999). 相似文献
3.
Min Han Rong-yang Wang Hong Liu Xiu-juan Zhu Fu-lan Wei Tao Lv Na-na Wang Li-hua Hu Guo-ju Li Dong-xu Liu Chun-ling Wang 《Journal of Zhejiang University. Science. B》2013,14(1):25-32
Objective:To investigate the relationship between growth patterns and mandibular posterior tooth-alveolar bone complex morphology in a Chinese population with normal occlusion.Methods:Forty-five patients with normal occlusion(23 males,22 females) were included in this study.Among these patients,20 displayed the vertical growth pattern,and 20 had the horizontal growth pattern,while the remaining patients displayed the average growth pattern.All of the patients underwent dental cone beam computed tomography(CBCT),which included the region of the mandibular posterior teeth and the alveolar.A linear regression analysis and a correlation analysis between the facial height index(FHI) and the alveolar bone morphology were performed.Results:The inclination of the molars,the thickness of the cortical bone,and the height of the mandibular bone differed significantly between patients with the horizontal growth pattern and those with the vertical growth pattern(P<0.05).Significant positive correlations were found between:the FHI and the inclination of the molars;the FHI and the thickness of the cortical bone;and the FHI and the height of the mandibular bone.Conclusions:The mandibular posterior tooth-alveolar bone complex morphology may be affected by growth patterns. 相似文献
4.
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
5.
吴立东 《浙江大学学报(A卷英文版)》2004,5(10):1270-1278
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 percentage of bone contact reached 60.1% (ranging from 49.2% to 70.4%); the average gap percentage was 32.8% (ranging from 25.1% to 39.9%); the maximum gap width was 2.97 mm and the average gap width was 0.77 mm. The average gap around the implant in the CASPAR group was only 9% of that in the manual group; the maximum and average gap widths were only about 26% of those in the manual group. On the other hand, the CASPAR group showed 33% higher bone contact than the manual group. Conclusion: With the use of robotics-assisted system, significant progress can be achieved for femoral preparation in total hip arthroplasty. 相似文献
6.
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
7.
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｔｈｅｔｒａｄｉｔｉｏｎａｌｍｅｔｈｏｄｔｏｓｔｕｄｙｔｈｅｐｅｒｆｏｒｍａｎｃｅｓｏｆｉｎｄｕｃｔｉｏｎｍｏｔｏｒｓｉｓｂａｓｅｄｏｎｔｈｅｃｏｎｃｅｐｔｏｆｅｑｕｉｖａｌｅｎｔｃｉｒｃｕｉｔ.Ｔｈｅｐａｒａｍｅｔｅｒｓｉｎｔｈｅｅｑｕｉｖａｌｅｎｔｃｉｒｃｕｉｔａｒｅｕｓｕａｌｌｙｏｂｔａｉｎｅｄｂｙｍａｇｎｅｔｉｃｃｉｒｃｕｉｔｃｏｍｐｕｔａｔｉｏｎ .Ｉｎｒｅ ｃｅｎｔｙｅａｒｓｉｔｈａｓｂｅｃｏｍｅｐｒａｃｔｉｃａｌｔｏｕｓｅｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈ… 相似文献
8.
Juan LI Lingfang SHI Xiayao ZHANG Luxi WENG Hong CHEN Jun LIN 《Journal of Zhejiang University. Science. B》2021,22(2):146
Midpalatal corticotomy-assisted rapid maxillary expansion(MCRME)is a minimally invasive treatment of maxillary transverse deficiency(MTD)in young adults.However,the effect of MCRME on respiratory function still needs to be determined.In this study,we evaluated the changes in maxillary morphology and the upper airway following MCRME using computational fluid dynamics(CFD).Twenty patients with MTD(8 males,12 females;mean age 20.55 years)had cone-beam computed tomography(CBCT)images taken before and after MCRME.The CBCT data were used to construct a threedimensional(3 D)upper airway model.The upper airway flow characteristics were simulated using CFD,and measurements were made based on the CBCT images and CFD.The results showed that the widths of the palatal bone and nasal cavity,and the intermolar width were increased significantly after MCRME.The volume of the nasal cavity and nasopharynx increased significantly,while there were no obvious changes in the volumes of the oropharynx and hypopharynx.CFD simulation of the upper airway showed that the pressure drop and maximum velocity of the upper airway decreased significantly after treatment.Our results suggest that in these young adults with MTD,increasing the maxillary width,upper airway volume,and quantity of airflow by MCRME substantially improved upper airway ventilation. 相似文献
9.
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
10.
ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅｉｔｓｃｌｉｎｉｃａｌｉｎｔｒｏｄｕｃｔｉｏｎ ,ｅｘｔｒａｃｏｒｐｏｒｅａｌｓｈｏｃｋｗａｖｅｌｉｔｈｏｔｒｉｐｓｙ(ＥＳＷＬ)ｈａｓｍａｉｎｔａｉｎｅｄａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｔｈｅｍａｎａｇｅｍｅｎｔｏｆｕｒｉｎａｒｙｃａｌｃｕｌｉ.Ｔｈｅｓｕｃｃｅｓｓｏｆｔｈｉｓｔｈｅｒａｐｅｕｔｉｃｐｒｏｃｅ ｄｕｒｅｄｅｐｅｎｄｓｏｎｔｈｅｅｆｆｅｃｔｉｖｅｄｉｓｉｎｔｅｇｒａｔｉｏｎａｎｄｅｖａｃｕａｔｉｏｎｏｆｓｔｏｎｅｄｅｂｒｉｓ.Ｈｏｗｅｖｅｒ,ｔｈｅｓｔ… 相似文献
11.
12.
Previous research has identified a negative correlation between developmental outcomes and length of early intervention programs. In the present investigation, these counterintuitive findings were examined on a sample of “at risk” children who had received a home-based infant development program and who had been enrolled at different age levels. Findings indicated that treatment length was negatively, but not significantly, correlated with developmental outcome. In addition, start age was found to be significantly negatively correlated with outcome, suggesting that certain developmental indices may decrease over time for certain populations. When the regression of time with start age was taken into account in the analyses, large and reliable treatment effects were observed at all start age levels. Results are discussed with respect to future research endeavors. 相似文献
13.
Fabio Savoldi Andy W. K. Yeung Ray Tanaka Lisa S. Mohammad Zadeh Carla Montalvao Michael M. Bornstein James K. H. Tsoi 《Anatomical sciences education》2021,14(1):62-70
Learning bone anatomy of the skull is a complex topic involving three-dimensional information. The impact of the use of human dry skulls and cone beam computed tomography (CBCT) imaging was investigated in the teaching of undergraduate dental students. Sixty-four first-year students in the University of Hong Kong were randomly divided into eight groups. Four teaching methods were tested: (1) CBCT followed by standard lecture, (2) CBCT followed by lecture with skulls, (3) standard lecture followed by CBCT, and (4) lecture with skulls followed by CBCT. After each, students were given a multiple-choice questionnaire to assess their objective learning outcome (20 questions) and a questionnaire for their subjective satisfaction (10 statements). Surveys were assessed with Cronbach's alpha, Kendall's tau-b, and principal components analysis. Data were analyzed with Student's t-test and a one-way ANOVA (significance α = 0.05). Standard lecture followed by CBCT showed the highest learning outcome score (81.6% ± 14.1%), but no significant difference was present among four teaching methods. Cone beam computed tomography followed by lecture with skulls scored the highest overall subjective satisfaction (4.9 ± 0.8 out of 6), but no significant difference was present among teaching methods. Nevertheless, students' perception of learning was positively influenced by the use of skulls (P = 0.018). The timing of administration of the CBCT did not affect students' subjective satisfaction or objective learning outcome. Students perceived to learn more by using skulls, but their objective learning outcomes were not significantly affected. A discrepancy seems to exist between students' perception of learning and their effective performance. 相似文献
14.
15.
１ Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｒｏｌｌｅｒｂｅａｒｉｎｇｓａｒｅｕｓｅｄｔｏｓｕｐｐｏｒｔｈｅａｖｙｌｏａｄｓ．Ｉｆｔｈｅｇｅｎｅｒａｔｒｉｃｅｓｏｆｒｏｌｌｅｒａｎｄｒａｃｅｗａｙｓａｒｅａｂｓｏｌｕｔｅｌｙｓｔｒａｉｇｈｔａｎｄｉｆｔｈｅｒｏｌｌｅｒｌｅｎｇｔｈｄｏｅｓｎｏｔｃｏｉｎｃｉｄｅｗｉｔｈｔｈｅｒａｃｅｗａｙｗｉｄｔｈ,ｔｈｅｎｎｏｔｗｉｔｈｓｔａｎｄｉｎｇｒｅｌａｔｉｖｅｌｙｌｉｇｈｔｌｏａｄｉｎｇ,ｅｄｇｅｓｔｒｅｓｓｅｓｗｉｌｌａｒｉｓｅａｔｔｈｅｅｎｄｓｏｆｔｈｅｃｏｎｔａ… 相似文献
16.
Local school districts often stagger daily start times for their schools in order to reduce busing costs. This paper uses data on all middle school students in Wake County, NC from 1999 to 2006 to identify the causal effect of daily start times on academic performance. Using variation in start times within schools over time, the effect is a two percentile point gain in math test scores – roughly fourteen percent of the black–white test score gap. I find similar results for reading scores and using variation in start times across schools. The effect is stronger for students in the lower end of the distribution of test scores. I find evidence supporting increased sleep as a mechanism through which start times affect test scores. Later start times compare favorably on cost grounds to other education interventions which result in similar test score gains. 相似文献
17.
在40侧头预部正中矢状切开标本和60侧下颌骨标本上,按口外翼下颌阻滞麻醉的设计要求,解剖观察了下牙槽神经、舌神经在翼下颌间隙的位置。测量了从下颌管下缘点和下颌角行口外翼下颌阻滞麻醉时的进针深度和角度。测得从下颌骨下缘点的进针深度为37mm;下颌角点的深度为30mm,穿刺针与下颌支后缘之间的角度为31°。对采用该法行口外阻滞麻醉的解剖学要点,优缺点进行了讨论。 相似文献
18.
19.
《Early education and development》2013,24(3):217-224
Previous research has identified a negative correlation between developmental outcomes and length of early intervention programs. In the present investigation, these counterintuitive findings were examined on a sample of "at risk" children who had received a home-based infant development program and who had been enrolled at different age levels. Findings indicated that treatment length was negatively, but not significantly, correlated with developmental outcome. In addition, start age was found to be significantly negatively correlated with outcome, suggesting that certain developmental indices may decrease over time for certain populations. When the regression of time with start age was taken into account in the analyses, large and reliable treatment effects were observed at all start age levels. Results are discussed with respect to future research endeavors. 相似文献
20.
Aluminum (Al) toxicity is the major factor limiting crop productivity in acid soils. In this study, a recombinant inbreed line (RIL) population derived from a cross between an A1 sensitive lowland indica rice variety IR1552 and an Al tolerant upland japonica rice variety Azucena, was used for mapping quantitative trait loci (QTLs) for A1 tolerance. Three QTLs for relative root length (RRL) were detected on chromosome 1, 9, 12, respectively, and I QTL for root length under Al stress is identical on chromosome I after one week and two weeks stress. Comparison of QTLs on chromosome 1 from different studies indicated an identical interval between C86 and RZ801 with gene(s) for Al tolerance. This interval provides an important start point for isolating genes responsible for A1 tolerance and understanding the genetic nature of Al tolerance in rice. Four Al induced ESTs located in this interval were screened by reverse Northern analysis and confirmed by Northern analysis. They would be candidate genes for the QTL. 相似文献