替牙期单侧完全性唇腭裂患者上颌骨复合体三维有限元模型的建立

目的 通过建立单侧完全性唇腭裂(UCLP)患者上颌骨复合体三维(3D)有限元模型,为后期利用3D有限元分析方法来研究该患者牙颌面畸形形成的机制及治疗提供条件.方法 选择1例8岁男性替牙期UCLP患者,提取锥形束CT(CBCT)图像,依次在Mimics 15.0医学图像处理软件中提取轮廓和截取范围、Geomagic St...     

种植钉辅助扩弓后腭中缝断裂的有限元模型建立

目的用三维有限元方法分析扩弓时上颌复合体应力蓄积至腭中缝完全断裂过程的力学特点,并验证模型有效性。方法建立包含种植钉的上颌复合体有限元模型。设定腭中缝屈服强度,以每5 ms加载0.25 mm水平横向位移为载荷,加载至腭中缝完全断裂,同时以临床1例种植钉辅助扩弓患者扩弓前后CT影像结果进行对比验证。结果 0～17 ms,腭中缝应力主要蓄积于腭骨水平板、种植钉周围、腭中缝中后方及颧颌缝; 18～60 ms,腭中缝中后部出现裂纹并向前后扩展; 61～71 ms,腭中缝中后部、前部、后部依次发生断裂。结论基于断裂力学的种植钉辅助扩弓的三维有限元模型有效,其计算的断裂过程结果更符合临床实际。研究结果为今后更有效研究种植钉辅助扩弓提供力学参考模型。     

传动矫治过程中后倾曲作用下上颌第一磨牙的位移及应力分析

背景:随着现代矫治技术的发展,发明一种高效的矫治器,一直是正畸学者们的研究热点之一。传动直丝弓矫治器就是在这种大环境下应运而生,能快速打开咬合、缩短疗程、治疗效率高,为疑难病例的治疗提供了新的思路。目前对传动直丝弓技术治疗初期,上颌第一磨牙位移趋势及上颌骨第一磨牙区应力分布情况,尚没有进行深入的研究。目的:建立生物相似性和力学相似性较高的传动直丝弓矫治器的三维有限元模型,获得上颌第一磨牙位移趋势及上颌骨第一磨牙区应力分布情况。方法:使用64排螺旋CT扫描,得到1例安氏Ⅱ类1分类的志愿者上颌牙列、上颌骨截面的DICOM格式的影像数据。采用Ansys workbench 13.0、Mimics 10.01、Unigraphics NX 6.0和GeomagicStudio 8.0软件相结合的方法,在Windows XP Service Pack 3系统中建立包括传动直丝弓矫治器、带环、澳丝、上颌骨、上颌牙齿及牙周膜的三维有限元模型。对模型进行加载,获得上颌第一磨牙位移趋势及上颌骨第一磨牙区应力分布情况。结果与结论:实验建立了由250 929个单元数,657 766个节点组成的传动直丝弓矫治器的三维有限元模型;获得了在后倾曲作用下上颌第一磨牙的位移趋势及上颌骨第一磨牙区的应力分布情况,利于分析传动直丝弓矫治力学体系并指导临床应用和矫治器改良。说明单纯后倾弯作用下,牙根将向颊侧骨皮质靠近,导致根尖部和上颌骨颊侧骨皮质区域的应力集中;这种应力集中可能会导致上颌第一磨牙颊侧根尖区出现牙根吸收。     

上颌骨性扩弓器在上颌骨横向发育不足中的应用及优势

文题释义： 上颌骨横向发育不足：是许多错牙合畸形的常见伴发症状，青少年发病率为8%-23%，成人正畸患者发病率约为10%，常表现为上颌基骨及牙弓狭窄、腭盖高拱、单侧或双侧后牙反或对刃、颊廊过大等。 上颌骨性扩弓器：通过4颗穿透双层骨皮质(腭骨和鼻底)的微种植体的辅助，将特制的螺旋扩弓器固定在硬腭后部，使螺旋扩弓器产生的扩弓力直接作用于上颌骨而不是牙列，从而产生骨性扩弓效应。 背景：上颌骨性扩弓器是一项上颌骨非手术扩弓技术，与传统的上颌快速扩弓器、微种植体辅助上颌快速扩弓和外科手术辅助上颌快速扩弓截然不同，为上颌骨横向发育不足的矫治提供了新思路、新方法，尤其为生长发育完成的成年患者提供了高效且微创的骨性扩弓效果。 目的：通过检索、筛选和阅读大量文献的方法，对上颌骨性扩弓器在上颌骨横向发育不足中的应用及优势进行系统性综述，为该类患者临床治疗方案确定提供科学的参考依据。 方法：对Cochrane图书馆、PubMed、Embase、Web of Science、中国学术期刊全文数据库(CNKI)、万方数据库(Wanfang)、中国生物医学文献数据库(CBM)等国内外常用数据库进行计算机检索，全面收集2019-05-31之前发表的与上颌骨性扩弓器相关的中英文文献。 结果与结论：上颌骨性扩弓器是矫治上颌骨横向发育不足的一种有效方法，其扩弓不受年龄限制，对于成人依然有良好的骨性扩弓效果。上颌骨性扩弓器使整个面中部结构扩张，导致腭中缝接近平行扩大，翼腭缝裂开，颧骨间宽度增加，包括鼻骨上区在内的整个鼻腔变宽，且牙齿颊倾、牙槽骨高度降低等不良反应较小。 ORCID: 0000-0001-7741-6045(张肖雅) 中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程     

Mimics辅助快速建立颅上颌复合体的三维有限元模型

背景：颅颌面部是骨骼系统中结构最复杂、功能最多样的的结构之一,要进行颅上颌骨复合体生物力学分析,就必须建立一个精准的三维有限元模型。 目的：探索快速建立完整颅上颌复合体三维有限元模型的方法。 方法：以牙列完整、咬合关系正常、磨牙为中性关系、牙周组织健康的成年志愿者作为建模素材,进行多层螺旋CT扫描,利用Mimics软件和MSC.Patran软件建立颅上颌复合体三维有限元模型。 结果与结论：探索出一条快速建立颅上颌复合体三维有限元模型的新方法。建立了三维坐标系下的可以从任意角度观察的健康人颅上颌复合体三维重建生物医学模型和三维有限元模型,由76 035个节点和373 819个单元组成。该模型具有较好的几何相似性和力学相似性。     

无托槽隐形矫治器内收上颌前牙的三维有限元分析

目的:通过有限元分析探讨无托槽隐形矫治器内收上颌前牙时的生物力学特性。方法:选取1名健康青年志愿者,获取其上颌骨及牙齿CBCT影像资料,构建上颌骨复合体及无托槽隐形矫治器的三维有限元模型,分析矫治器施力控根内收（工况一）以及矫治器施力控根内收辅以微种植钉与Power arm 150 g牵引力内收（工况二）下牙齿位移趋势及牙周膜应力分布情况。结果:工况一,前牙的冠根位移差分别为113.3、92.2、128.6 μm,最大牙周膜等效应力为79.6 kPa;工况二,前牙冠根位移差分别为89.3、74.3、184.2 μm,最大牙周膜等效应力为37.5 kPa。结论:无托槽隐形矫治器联合微种植钉和Power arm可改善上颌切牙倾斜移动的趋势并减少牙根吸收的风险,但对于尖牙的控制尚不足。     

前方牵引联合腭部扩弓对颅面骨缝应力分布的三维有限元研究

目的:建立颅面复合体-牙列的模型,分析上颌前牵引联合腭部扩弓时,其牵引角度的不同对颅面骨缝应力分布的影响。方法:利用Mimics、Geo-magic软件建立颅面复合体-牙列的有限元模型,在进行腭部扩展的同时与尖牙近中处施加1000 g作用力,方向分别与眶耳平面成10°,20°,30°,40°,50°,60°,采用ANSYS 10.0软件分析复合体各骨缝的主应力变化。结果:随着牵引角度的逐渐增大,颧颌缝,颧额缝主应力变化趋势不明显;在20°的牵引角度主应力最小;颧颞缝、蝶上颌缝的主应力基本线性减小;鼻上颌缝的主应力基本线性增大;在40°~50°的牵引角度时,各主应力接近。结论:在伴有腭部扩弓的情况下,不同的牵引角度对颅面骨缝的影响不同,随着牵引角度的增大,上颌骨由前上旋转逐渐变为前下,在40°~50°时,上颌骨旋转不明显。     

半侧上颌骨缺损赝复体修复固位方案的生物力学评价

目的 对3种单侧上颌骨缺损赝复体修复方式——卡环固位、一根/两根颧种植与卡环联合固位进行生物力学评价。方法 基于CT扫描数据建立正常人颅骨的三维有限元模型,通过三维有限元法计算分析3种重建模型中上颌复合体的应力分布,综合比较赝复体、基牙、卡环、种植体、颧骨的应力水平。结果 单一的卡环固位,基牙应力峰值达130.7 MPa,赝复体产生位移4.439 mm,卡环应力峰值达452.4 MPa,健侧眶缘应力为23.32 MPa;加入一根颧种植后,卡环应力减小至118.1 MPa,基牙应力峰值为31.12 MPa,健侧眶缘应力仅为5.387 MPa。两根颧种植体固位方式下,颧骨应力由66.11 MPa减小到48.12 MPa;颧种植体上的最大应力也由500.2 MPa降至313.8 MPa。 结论 颧种植与卡环联合固位,颌面骨骼应力分布更符合咬合力传导规律。研究结果将为人体上颌单侧缺损重建方案设计和优化提供重要参考数据。     

上颌扩弓对颞下颌关节应力影响的有限元分析

目的 通过三维有限元法对比扩弓前和放置扩弓器时颞下颌关节（temporomandibular joint, TMJ）内部各组织应力分布情况。方法 根据1名上颌牙弓狭窄患者CBCT影像资料，构建扩弓前和包含扩弓器的TMJ三维有限元模型，对模型加载相同的肌力和边界约束，观察TMJ髁突、关节盘、关节窝的等效应力、最大主应力和最小主应力。结果 扩弓前TMJ等效应力主要分布在下颌支前缘、髁突前斜面、关节盘中间带和后带以及关节窝顶部。放置扩弓器时,TMJ应力分布特征与扩弓前基本一致，应力虽然明显增加，但应力分布区域更加均匀；髁突和关节盘应力向前、向外侧移动，髁突后斜面表现出更加均匀的最大主应力分布范围。结论 上颌扩弓器产生的矫形力能够使TMJ应力增加，诱导髁突发生组织改建，协调髁突和关节盘的关系。临床上对于牙弓狭窄的患者应该采用合适的手段进行扩弓矫治。     

以螺旋CT数据建立的颅底三维有限元模型

背景:近年来国内外学者进行了大量生物力学实验研究,试图解释颅脑损伤的发生过程和受力大小与损伤部位的相关性。但是目前针对颅底骨折原因的研究主要是直接暴力,对于间接暴力作用于颅底后颅底的应力分布情况尚无报道。目的:利用螺旋CT数据、三维重建软件及有限元分析软件,在普通PC机建立颅底三维有限元模型。方法:选择正常成年女性作为建模对象,无头颈部损伤、手术及其他病史,CT扫描前进行X射线常规检查排除器质性疾病。头部螺旋CT薄层扫描后,将图像数据输入医用图像与三维重建软件MIMICS中,建立颅底的三维可视化模型。将该模型简化优化后,导入有限元分析软件ANSYS10.0中,建立颅底的三维有限元模型。结果与结论:建立了由额骨、蝶骨、筛骨、颞骨、枕骨等共同组成的颅底实体模型,由于成年人骨缝闭合,所以将其视为一个整体。对实体模型划分网格,得到颅底的三维有限元模型,共有51053个单元,80273个节点。提示所建立的颅底有限元模型外形逼真,几何相似性好,可以用来进行颅底骨折的生物力学研究。     

James Jeffray: Observations on the heart and on the peculiarities of the foetus

James Jeffray, Regius Professor of Anatomy in the University of Glasgow (1790–1848), published his lectures on the heart as a monograph entitled Observations on the Heart and on the Peculiarities of the Foetus (Jeffray, 1835), in which he considered controversies about the adult heart, such as the arrangement of the coronary vessels and the function of the aortic and pulmonary sinuses, and about the fetal circulation. His sources were the works of Senac, Lower, Vieussens, Eustachius, Mery, Haller, Winslow, and Sabatier which were available from the Hunterian bequest. Jeffray supplemented his own material with Hunterian specimens for the illustrations. He supported the theory that blood from the superior and inferior venae cavae crossed in the right atrium, that from the superior cava being destined for the right ventricle and from the inferior passing through the foramen ovale to the left atrium. He also held that the valve of the inferior vena cava directed the bloodflow from that vessel to the foramen ovale. These views conflicted with those of John Bell (1763–1820), a successful Edinburgh anatomist and surgeon whose opinions are attacked several times in the publication. Regarding the placenta, Jeffray may have been deliberately vague about whether the fetal and maternal circulations are continuous or separate, an issue resolved by William Hunter in the previous century. Clin. Anat. 12:35–42, 1999. © 1999 Wiley‐Liss, Inc.     

Study on the interference of ticlopidine on the immune system

In-vitro and ex-vivo studies have been performed in order to investigate the possible interference of ticlopidine on different lymphocyte parameters. In vitro, ticlopidine displays a dose-dependent inhibition of both spontaneous and lectin-induced 3H-thymidine incorporation by normal lymphocytes. Moreover the highest drug concentrations also reduce the in-vitro PWM-stimulated Ig synthesis. Lymphocyte tests performed in healthy volunteers after a 10-day oral treatment (250 mg/day) show only a slight reduction of PHA- and ConA-induced proliferative responses and in-vitro PWM-stimulated Ig synthesis. The values found after treatment however remain within the normal range, excluding a clear interference of ticlopidine on the immune parameters tested. In addition the treatment does not affect the white blood cells nor the lymphocyte subset distribution identified by the monoclonal antibodies OKT3, OKT4 and OKT8.     

Reflections on the mechanical structure of the base of the skull and on the face

Using thick sections of the base of the skull and face their mechanical structure is viewed from the engineering aspect and the anatomic solutions evolved are compared with those selected by Aerospatiale engineers for the concept and development of the Airbus. It is concluded that the anterior and middle cranial fossae, together with the face, constitute an inseparable mechanical assembly each of whose component units participate in the rigidity of the others. Since this mechanical assembly must provide maximal rigidity for minimal weight, this suggests that aeronautical solutions should throw much light on the detail of construction of the skull and face. Indeed, the rigidity and lightness of the latter are obtained by means of solutions familiar in aeronautics: the reliance on thin-shelled beams with a honeycomb filling, the diploe analogous to a preconstrained composite or sandwich structure, a system of frames, struts and stiffeners, and the use of fillets at the sites of junction of struts.     

超声造影方法的再探讨

目的探讨造影剂（Sono Vue）和与之相匹配的对比脉冲系列成像技术（CPS）在超声造影（contrast—enhanced uhrasonography）中的方法。方法对不同的造影部位及不同造影目的采用了不同的造影参数设置。结果84例患者除1例注射时刺破血管造成造影剂外渗影响造影效果外，其余83例效果满意。超声造影检查对肿块定性诊断的准确率优于CT、MRI，心肌灌注检查为临床提供方便、可靠的无创方法。结论应根据使用的造影剂和成像技术及造影目的设置相应的造影参数。     

Studies on the influence of the structural modifications in the tracer on the immunoassay of progesterone

The main objective of the present study was to examine the influence of different bridges in radioiodinated tracers on the assay performance of progesterone using antibodies. Three homologous and two heterologous immunoassay systems for the measurement of progesterone in human serum are described. Using an antiserum raised against progesterone-11alpha-hemisuccinate-bovine serum albumin (BSA), assays with homologous radioligands, namely progesterone-11alpha-hemisuccinate-125I-tyrosine methyl ester (TME) and progesterone-11alpha-hemisuccinate-125I-histamine, heterologous bridge radioligand, namely progesterone-11alpha-hemiphthalate-125I-TME, and a heterologous site radioligand namely progesterone-3-(O-carboxymethyl) oxime (CMO)-125I-histamine were optimized. A homologous assay system, using antiserum raised against progesterone-3-carboxymethyl oxime-BSA and progesterone-3-CMO-125I-histamine as the radioligand was also optimized to develop a radio-immunoassay (RIA) for serum progesterone. Amongst the two homologous radioligands, viz., progesterone-11alpha-hemisuccinate-125I-histamine and the corresponding TME conjugate tracer, the former yielded a standard curve with a higher slope (-0.6) as compared to the latter (-0.5). The heterologous bridge system with progesterone-11alpha-hemiphthalate-125I-TME resulted in a more sensitive assay (slope of -0.8) than the homologous tracers, whilst the heterologous site radioligand, viz., progesterone-3-CMO-125I-histamine gave the most sensitive assay (slope of -1.2). The homologous assay with antiserum against progesterone-3-CMO-BSA and progesterone-3-CMO-125I-histamine tracer gave a standard curve having a slope of -0.97. The two antibodies developed against progesterone, viz., progesterone-11alpha-hemisuccinate-BSA and progesterone-3-CMO-BSA were characterized for their titre, sensitivity, and specificity. Considering the slope, sensitivity, cross-reactivity, and the quality of tracer, the assay system using antiserum against progesterone-11alpha-hemisuccinate-BSA and progesterone-3-CMO-125I-histamine was found to be suitable for the development of RIA for serum progesterone. The bridges used in an immunogen for production of antibodies, as well as in the preparation of tracer, have a great influence on the assay characteristics.