下颌髁突与关节窝解剖相关性测量和分析

目的 :探索颞下颌关节骨性结构内外径之间的匹配特点。方法 :下颌骨髁突和颞骨关节窝完整的颅骨标本 2 4副 ,游标卡尺和分规测量。结果 :髁突内外径 (1.95± 0 .2 4 )cm明显小于关节窝内外径(2 .4 3± 0 .18)cm ;双侧髁突内极间距 (8.32± 0 .5 5 )cm明显大于关节窝内侧间距 (7.6 3± 0 .30 )cm(P <0 .0 1) ,而髁突外极间距 (12 .19± 0 .5 8)cm与关节窝外侧间距 (12 .13± 0 .5 8)cm之间无明显差异。髁突内外径的变异系数明显大于其他测量指标的变异系数 (P <0 .0 1)。结论 :双侧颞下颌关节髁突及关节窝间距之间具有较好的匹配性 ,单侧髁突与关节窝之间的匹配性较差 ,髁突内极凸出程度的变异较大     

正常开闭口时髁突运动的轨迹特征

目的　通过对正常人群下颌运动中髁突运动的测量记录 ,从而确定正常在开闭口运动中髁突的运动特征。方法　正常 38人 ,其中男女各 19人 ,平均年龄 18.7岁。应用CADIAXⅢ型 (Com puterAidedDiagnosisAxiogragh)髁突运动仪 ,记录下颌在各种边缘运动时的髁突运动情况 ,对开闭口时的髁突运动情况加以分析。结果　定性研究结果表明正常髁突运动轨迹对称 ,光滑 ,重复性好。男女性别无显著差异。在大张口时髁突相对于参考位置 (ReferencePosition)的最大位移左侧为 16 .0 2± 4 .2 7mm ,右侧为 16 .33± 5 .6 4mm ,髁突在位移 5mm时的矢状面倾斜度分别为右侧 35 .2 3± 8.18°,左侧 33.10± 8.6 6° ;在水平面内的髁突倾斜度右侧为 - 2 .0 0± 2 .6 7° ,左侧为 0 .39± 2 .18° ,大张口时绞链轴的旋转度 (GAMMA值 )为 2 6 .18± 6 .2 2°。结论　正常髁突运动轨迹有其典型的轨迹特征 ,但也存在较大的个体差异     

RG实验低熔瓷与钛的结合性能分析

目的　测试作者自行研制的RG实验低熔瓷与钛的结合性能。方法　铸造 1 0mm×5mm× 1 4mm钛片 5个 ,于钛片表面依次熔附RG实验遮色瓷和牙本质瓷总厚度 1mm。采用扫描电镜观察钛瓷界面形貌并做能谱分析。采用铸造法制备 2 8mm× 3mm× 0 5mm的NiCr合金试件6个 ,纯钛试件 1 8个。于NiCr合金试件中份 8mm× 3mm处熔附 1mmVita常用瓷 ;钛试件分为 3组 ,每组 6个 ,于试件中份 8mm× 3mm处分别熔附 1mmRG实验低熔瓷、VITATITANKERAMLK瓷和NoritakesuperporcelainTi 2 2瓷。在实验机上采用 3点弯曲法测试金瓷分离时的载荷。采用金瓷修复体制作方法制作RG实验钛瓷冠。结果　扫描电镜观察发现遮色瓷与钛之间无明显缝隙存在 ,遮色瓷与钛之间存在一个约 1 μm过渡层 ,能谱分析发现该过渡层的主要化学元素为Ti、Si、O。NiCr合金 VITA瓷试件的分离加载为 (1 2 733± 3 2 97)N ,钛 VITATITAN、钛 Noritake瓷试件和钛 RG实验瓷的分离加载分别为 (7 2 33± 2 539)N、(5 533± 1 1 99)N和 (6 31 6± 1 433)N。经统计检验 ,3种钛瓷试件之间差异无显著性 (P >0 0 5) ;而 3种钛瓷样本的分离加载均明显低于NiCr合金与瓷的分离载荷 ,差异有极显著性 (P <0 0 1 )。钛瓷冠瓷面完整无裂纹。结论　RG瓷与钛具有良好的结合     

纯钛拉力螺钉在髁状突骨折中的应用

自 1998 0 7～ 2 0 0 1 0 7,我们采用纯钛拉力螺钉 (ＴＳＯ )对下颌骨髁突骨折进行轴向拉力螺钉固定术 ,手术效果满意 ,现报告如下 :1　资料与方法1.1　一般资料选择 9例髁突关节囊外横断性骨折的患者 ,男 6例 ,女 3例 ,年龄 18～ 63岁 ,平均年龄 3 6岁。其中左侧髁突骨折 4例 ,右侧髁突骨折 3例 ,双侧骨折 2例 ;合并下颌骨他处骨折 5例 ;内侧移位 4例 ,外侧移位 2例 ,前移位 2例 ,无明显移位 1例。1.2　手术材料采用北京有色金属研究院提供的纯钛原料 ,经山西太航仪表厂加工为纯钛拉力螺钉 ,直径 2ｍｍ ,长度为 45、5 0、5 5、60、65、70…     

自体肋骨软骨移植重建羊下颌骨髁突的实验研究

目的：探讨白体肋骨软骨移植（CCG）N建生长期山羊下颌髁突的生长与改建。方法：6只6个月龄雄性山羊左侧颞下颌关节作为正常对照侧，右侧手术切除髁突但保留关节盘行CCG（软骨长度3-5mm）重建髁突。术后即刻、1个月、6个月、18个月行螺旋CT扫描头颅，观察移植骨改建，并通过三维头影测量记录下颌支高度的变化。2名测量者分别进行测量，其中一名在1个月后重复测量，采用SPSS13．0软件包对测量数据分别进行配对t检验。结果：术后移植骨逐步改建，18个月后重建侧与正常侧髁突形态接近；测量者之间和测量者自身2次的测量结果无显著性差异（P〉0．05）；术后即刻、1个月、6个月和18个月，正常对照侧平均下颌支高度分别为58．2mm、61．3mm、68．8mm和76．7mm，实验侧平均下颌支高度分别为60．0mm、59．6mm、68．0mm和74．8mm。结论：保留关节盘的自体CCG（软骨长度3—5mm）重建生长期山羊下颌髁突后，能够改建成接近正常髁突的形态，并维持该侧下颌骨的同步生长发育。     

下颌骨髁突骨折手术治疗的体会

髁突骨折发生率约占下颌骨骨折的 2 5 %左右。近年来我科对不能保守治疗的病例采取手术复位固定的方法 ,取得了较为满意的疗效 ,现报告如下。　　作者单位 :0 5 3 0 0 0衡水市哈励逊国际和平医院口腔科一、临床资料本组 11例中男性 9例 ,女性 2例。年龄 3岁～ 48岁。其中 3～ 10岁 2例 ,10～ 2 0岁 4例 ,2 0～ 30岁 3例 ,30～ 5 0岁 2例。单侧髁突骨折 7例 ,双侧 4例。 11例同时合并下颌骨颏部与体部骨折。外伤类型与原因 :6例 8侧为髁突高位骨折 ,5例 7侧为低位骨折。髁突骨折片与下颌升支成角移位 (>45度 ) ,或髁突脱位至关节凹远处 ,有的…     

半侧颜面短小畸形患儿非病变侧下颌骨形态改变特点

目的通过几何形态学方法分析比较半侧颜面短小（HFM）畸形患儿下颌骨非病变侧与正常下颌骨的形态差异。 方法收集2015年1月1日至2021年12月31日广州市妇女儿童医疗中心收治的16例HFM畸形Ⅱb及Ⅲ型患儿（1岁以下）三维CT数据,以同时期同年龄段16例无颅颌面畸形的儿童下颌骨CT为对照。对CT数据进行抽提三维模型,绘制非病变侧下颌骨水平面及矢状面投影,对投影进行标点,转化为坐标数据导入MorphoJ进行典型变量分析。将非病变侧下颌骨三维模型同正常组下颌骨模型三维叠印,显示患者组非病变侧下颌骨三维形态特点。 结果患者组典型非病变侧典型下颌骨同正常组典型下颌骨三维叠印提示,患者组非病变侧髁突向内偏曲,升支后倾,体部略外展,颏部略向前突。典型变量分析结果显示,患者组与对照组在水平面投影（马氏距离=6.472 9,P<0.001;普氏距离=0.047 7,P=0.026 2）和矢状面投影（马氏距离=6.422 7,P<0.001;普氏距离=0.059 6,P=0.000 6）差异均存在统计学意义。水平面投影可见患者组非病变侧颏部向对侧偏斜,颏部与体部交界区弯曲度较大,髁突横轴相对于体部向外旋转;矢状面投影可见患者组非病变侧体部-升支弯曲度减小,髁突沿长轴方向缩短。 结论HFM畸形患儿非病变侧较正常组差异明显,表现为颏部延长、颏部与体部交界区水平弯曲度较大、体部-升支矢状弯曲度减小、髁突横轴相对于体部向外旋、髁突沿长轴方向缩短等变化。     

氧化铝预制体烧结温度对GI-Ⅱ型渗透陶瓷性能的影响

目的 :本实验旨在研究预制体烧结温度对最终熔融渗透氧化铝 -玻璃陶瓷复合体 (GI -Ⅱ型渗透陶瓷 )相关性能的影响。方法 :氧化铝浆料涂粉涂塑成长条状杆状试件 ,分别在 10 5 0、110 0、115 0、12 0 0℃烧结 ,然后在112 5℃渗入玻璃 ,试件研磨成 1.9mm× 6 .5mm× 2 5mm大小 ,然后测三点弯曲强度。记录条状试件在制作过程的收缩。结果 :预制体烧结温度升高 ,使渗透陶瓷收缩从 0 .2 0 4%增大到 0 .418% ,但是并未明显提高陶瓷强度。各组强度值分别为 (36 3 .80± 87.90 )MPa ,(380 .40± 5 5 .10 )MPa ,(36 1.2 0± 5 3 .2 0 )MPa ,(388.40± 82 .80 )MPa ,Weibull模数分别是 4.41,6 .88,6 .35 ,4.49。 12 0 0℃组强度稍高 ,但无统计学意义。结论 :从材料收缩小和强度高的要求选择 ,氧化铝预制体烧结温度可选在 110 0℃～ 115 0℃。     

下颌后牙区牙槽嵴萎缩的解剖及X线测量

目的　为下颌后牙区牙槽嵴增高术提供定量指标。方法　对 90名 50岁以上中老年患者的曲面体层片及 89具成人离体下颌骨后牙区不同部位高度进行了测量。结果　①颏孔上缘至牙槽嵴顶高度 ,X线片有牙侧(1 5 .91± 1 .85)mm ,无牙侧 (9.0 7± 2 .48)mm ,平均值相差 6 .84mm ;下颌骨标本有牙侧 (1 3 .95± 2 .45)mm ,无牙侧 (8.77± 2 .75)mm ,平均值相差 5 .1 8mm。②颏孔区下颌体高度 ,X线片有牙侧 (33 .64± 2 .69)mm ,无牙侧 (2 3 .65± 4 .2 8)mm ,平均值相差 9.99mm ;下颌骨标本有牙侧 (31 .65± 3 .0 9)mm ,无牙侧 (2 4 .67± 3 .88)mm ,平均值相差 6 .98mm。③下颌后牙区下颌体高度 ,X线片线片有牙侧 (30 .68± 2 .76)mm ,无牙侧 (2 0 .96± 4 .1 5)mm ,平均值相差 9.72mm ;下颌骨标本有牙侧 (2 9.1 5± 2 .91 )mm ,无牙侧 (2 3 .0 3± 4 .1 1 )mm ,平均值相差 6 .1 2mm。结论　选择颏孔和颏孔后 1 .0cm分别作为双尖牙区、磨牙区下颌骨高度的测量标志点 ,方法简单 ,位置较恒定 ,临床使用方便。下颌后牙区颌骨垂直吸收 6～ 1 0mm ,可供该区牙槽嵴增高术参考     

颞颌关节侧位校正断层摄影技术

一般颞颌关节侧位断层不是髁状突真正的侧位影像,因为髁状突的横轴一髁状突内外径联线与冠状面有一定的角度。经我院放射科测量,最大为36°,最小为0°,并且两侧髁状突的角度大部不一致。因此一般颞颌关节侧位断层不是髁状突及关节凹的侧位影像。     

Correction of condylar displacement following intraoral vertical ramus osteotomy

Fifteen patients who demonstrated condylar sag after intraoral vertical ramus osteotomy for the correction of mandibular prognathism were treated nonsurgically to establish the desired postoperative occlusion. A mean inferior displacement of 3.33 mm and anterior displacement of 2.18 mm were observed tomographically after surgery. Postoperatively, a geometric splint was constructed to compensate for the magnitude of condylar displacement and was used to replace the original splint to hold the distal segment in an overcorrected position. Skeletal fixation was maintained for 5 to 6 weeks. Tomographic evaluation of the temporomandibular joint (TMJ) during maxillomandibular fixation showed a slight superior (1.03 mm) and posterior (0.51 mm) movement of the condyle in the fossa. After release of fixation and removal of splint, a further superior (2.05 mm) and posterior (1.01 mm) repositioning of the condyle was observed. This later movement correlated with the placement of light class III elastic traction to seat the condyles into the glenoid fossae and establish a class I occlusion. Temporomandibular joint tomograms confirmed complete seating of the condyles in the fossa and lateral cephalograms demonstrated a corresponding change in the position of the mandible to the desired postoperative position. This technique has been effective in preventing postoperative malocclusion resulting from condylar sag.     

Biomechanical calculation of human TM joint loading with jaw opening

A three-dimensional, static mathematical calculation of the stomatognathic system was done to predict total temporomandibular joint (TMJ) loading at different levels of jaw opening. The model assumed that muscle forces acting on the mandible could be simulated by a combination of contractile components (CCs) and elastic components (ECs) and that static equilibrium existed within the body of the mandible. The model also imposed the constraint that any generated joint reaction force would act on the centre of the condyle. The results of the model demonstrated that under all conditions of opening and for all values of the elastic modulus selected, the forces between the TMJ condyle and the articular eminence were compressive in nature. The compressive force magnitude increased from 2.7 to 27.6 N incrementally as the jaw opened from 10 to 40 mm. Overall data in this study indicated that the TMJ tissues undergo low levels of compression at open positions up to 40 mm. Finally, the condition of trismus (increased jaw closing activation with opening) was simulated, the joint reaction force at 20 mm opening increased from 7.7 to 64.9 N with only a 20% activation of the closers.     

Motion of the human mandibular condyle during mastication

It has been reported that loading to the mandible during closing movement makes the condylar path move more in the superior direction than that during the free closing movement. In this study, the hypothesis was tested that the displacement of the condyle on the chewing side is greater in the direction of the mandibular fossa than that on the non-chewing side. Using a six-degrees-of-freedom jaw movement recording system, we recorded condylar motion in 12 healthy adults without TMD, during the chewing of a large hard gummy jelly. The maximum displacements at the condyle on the chewing side from the maximum intercuspation (CO) position were significantly larger in the superior and medial directions at the initial stage and in the posterior direction at all stages (0.5 mm, 0.5 mm, and 0.6 mm, respectively) than those on the non-chewing side (0.0 mm, 0.1 mm, and 0.1 mm, respectively). This suggests that, in healthy adults, the condyles at CO are located in a position such that excessive load is not applied to the temporomandibular joint when there are the aforementioned displacements.     

Determination of elastic modulus of the components at dentin-resin interface using the ultrasonic device

The purpose of this study was to determine the elastic moduli of the components at resin-dentin interface with the use of an ultrasonic device. Dentin plates were obtained from freshly extracted bovine incisors with a shape in rectangular form. Resin composites and bonding agents were polymerized and trimmed in the same shape as the dentin specimens. The ultrasonic equipment employed in this study was comprised of a Pulser-Receiver, transducers, and an oscilloscope. Each elastic modulus was determined by measuring the longitudinal and shear wave sound velocities. The mean elastic modulus of mineralized dentin was 17.4 GPa, while that of demineralized dentin was 1.4 GPa. When the demineralized dentin was immersed in bonding agents, the elastic modulus changed to 3.7-4.7 GPa, and these values were significantly higher than those of demineralized dentin. A gradient in elastic modulus was detected as the analysis shifted from the dentin side to the resin composite.     

Structural and mechanical properties of mandibular condylar bone

The trabecular bone of the mandibular condyle is structurally anisotropic and heterogeneous. We hypothesized that its apparent elastic moduli are also anisotropic and heterogeneous, and depend on trabecular density and orientation. Eleven condyles were scanned with a micro-CT system. Volumes of interest were selected for the construction of finite element models. We simulated compressive and shear tests to determine the principal mechanical directions and the apparent elastic moduli. Compressive moduli were relatively large in directions acting in the sagittal plane, and small in the mediolateral direction. The degree of mechanical anisotropy ranged from 4.7 to 10.8. Shear moduli were largest in the sagittal plane and smallest in the transverse plane. The magnitudes of the moduli varied with the condylar region and were proportional to the bone volume fraction. Furthermore, principal mechanical direction correlated significantly with principal structural direction. It was concluded that variation in trabecular structure coincides with variation in apparent mechanical properties.     

The functional shift of the mandible in unilateral posterior crossbite and the adaptation of the temporomandibular joints: a pilot study.

Changes in the functional shift of the mandibular midline and the condyles were studied during treatment of unilateral posterior crossbite in six children, aged 7-11 years. An expansion plate with covered occlusal surfaces was used as a reflex-releasing stabilizing splint during an initial diagnostic phase (I) in order to determine the structural (i.e. non-guided) position of the mandible. The same plate was used for expansion and retention (phase II), followed by a post-retention phase (III) without the appliance. Before and after each phase, the functional shift was determined kinesiographically and on transcranial radiographs by concurrent recordings with and without the splint. Transverse mandibular position was also recorded on cephalometric radiographs. Prior to phase I, the mandibular midline deviated more than 2 mm and, in occlusion (ICP), the condyles showed normally centred positions in the sagittal plane. With the splint, the condyle on the crossbite side was displaced 2.4 mm (P < 0.05) forwards compared with the ICP, while the position of the condyle on the non-crossbite side was unaltered. After phase III, the deviation of the midline had been eliminated. Sagittal condylar positions in the ICP still did not deviate from the normal, and the splint position was now obtained by symmetrical forward movement of both condyles (1.3 and 1.4 mm). These findings suggest that the TMJs adapted to displacements of the mandible by condylar growth or surface modelling of the fossa. The rest position remained directly caudal to the ICP during treatment. Thus, the splint position, rather than the rest position should be used to determine the therapeutic position of the mandible.     

犬下颌骨单侧不全截骨牵张时牵张侧位移状况有限元分析

目的 运用犬下颌单侧不全截骨牵张成骨有限元模型,计算下颌骨在牵张过程中牵张侧各部分位移状况。方法 有限元模型模拟犬下颌单侧不全截骨牵张,观察当滑动骨块未被牵开和被牵开时牵张侧关节、下颌角、喙突及牙齿等6个标志点的位移状况。结果 下颌滑动骨块未被牵开时牵张侧第五臼齿、髁状突前斜面前缘中点所受最大主应力为压应力,髁状突后斜面后缘中点为拉应力,各标志点在空间X、Y、Z三轴位移不明显;当下颌骨滑动骨块被牵开1 mm时,上述各点位移明显增加。结论 从牵张侧观察,牵张侧下颌骨在矢状平面上和冠状平面上都有以髁突顶点(横嵴中点)为中心的逆时针旋转趋势。     

Anisotropic elastic properties of cancellous bone from a human edentulous mandible

The elastic moduli have not been reported for cancellous bone from the edentulous mandible. Accurate values are needed for finite element modeling of the mandible. The aim of this study was to determine elastic modulus values in three orthogonal directions for cancellous bone taken from an edentulous jaw and to relate these values to apparent density and volume fraction. Seven samples were obtained from the edentulous mandible of a 74-year-old female. Young's modulus was determined by compression testing of cubes cut with the faces aligned with the anatomic axes. Bone volume fraction averaged 0.33 (SD 0.14) and apparent density averaged 0.55 g/cc (SD 0.29). Young's modulus was greatest in the mesio-distal direction (mean 907 MPa, SD 849 MPa), followed by the bucco-lingual (mean 511 MPa, SD 565 MPa) and infero-superior direction (mean 114 MPa, SD 78 MPa). The infero-superior direction was less than the bucco-lingual (P = 0.03) and mesio-distal (P = 0.002). The mesio-distal and bucco-lingual directions could not be shown to be different (P = 0.32). This suggests a model of transverse isotropy for cancellous bone in the jaw, where the symmetry axis is along the infero-superior (weakest) direction.     

面部不对称畸形患者下颌骨核素骨扫描临床分析

目的：研究面部不对称畸形患者下颌骨的放射性核素分布,帮助临床医师确定治疗时机和治疗方式。方法：29例面部对称者作为正常对照组。实验组为207例面部不对称畸形患者,测量29例面部对称和207例面部不对称畸形患者下颌骨不同部位的放射性计数,比较髁突、下颌支、下颌体99mTc-MDP摄入量百分比。采用SPSS13.0软件包对数据进行统计学处理。结果：成年和未成年患者的面部不对称畸形患者下颌骨99mTc-MDP摄入量有显著差异,男性和女性的下颌骨99mTc-MDP摄入量无显著差异。在下颌骨发育活性异常的患者中,99mTc-MDP摄取量差异值在髁突、下颌体、下颌支依次为(22.50±1.67)%、(6.93±1.02)%和(13.67±0.95)%。髁突的摄入量差异值最大。结论：下颌骨的生长发育与身体生长发育有所不同。放射性核素骨扫描可对下颌骨发育情况做出评价,为临床医师确定治疗时机与方式提供依据。     

输送盘牵张成骨重建下颌髁突的骨密度和力学性能变化

目的 探讨运用输送盘牵张成骨术重建髁突的骨密度和力学性能变化.方法 成年山羊16只.截除右侧髁突后运用输送盘牵张成骨术重建髁突,左侧作为正常对照组.牵张结束后24周处死所有动物.采用双能X线吸收法和压缩力学性能测试技术.定量分析并对比两侧髁突的骨密度和压缩力学性能变化.结果 手术侧髁突骨密度较正常侧显著升高;其轴向弹性模量和最大应力较正常侧显著升高,横向弹性模量和最大应力两侧无显著性差异,轴向和横向最大应变两侧均无显著性差异.髁突骨松质的力学性能具有明显的各向异性.结论 运用输送盘牵张成骨术重建的髁突的骨密度和生物力学性能明显升高;这种适应性改建与颞下颌关节的功能刺激直接相关.