基于二维DR的颅面硬组织与软组织拟合的研究

目的:以数字化X线摄影片(digital radiograph,DR)图像和激光扫描为数据源,三维重建颅面硬组织和软组织,并进行硬软组织的有效拟合,以期为治疗方案确定、手术方法选择和提高医患交流的水平提供平台.方法:在志愿者面部贴定铅点,拍摄头颅正侧位DR片.利用基于二维DR数据的颅面硬组织三维重建系统进行硬组织形变建模.获得颅面部硬组织模型.利用激光扫描数据进行面部软组织三维重建,获得面部软组织三维模型.然后通过铅点坐标的匹配,将颅面硬组织与面部软组织进行拟合.结果:分别重建了能反映真实颅面部组织结构的硬组织三维模型和面部软组织三维模型,并实现了颅面部硬组织与软组织的有效拟合.结论:本研究实现了颅颌面三维结构的有效重建和拟合,为进一步进行正颌手术模拟和容貌预测奠定了基础.拟合结果真实可靠,能够用于临床.     

基于二维DR数据的颅面硬组织三维重建系统的建立

目的:以数字化X线摄影片(DR)图像为数据源,在Windows XP平台上,利用VC++6.0、VTK工具研发颅面硬组织三维重建系统,为治疗方案确定、手术方法选择和提高医患交流的水平提供平台.方法:以CT影像为基础构建的头颅作为标准模板,确立其三维坐标系,选取64个特征点,作为初始特征点.调整患者DR,使其与标准模板的坐标系一致.调整DR上的特征点作为目标特征点.根据一定形变算法,对标准模板进行上下颌分离形变、融合,得到患者颅面硬组织模型.结果:重建了能基本反映真实颅面硬组织结构的三维模型,其图像逼真,能够动态旋转,任意缩放.结论:本系统硬组织重建突破常规,分离独立形变后再融合,实现了咬合关系的基本重建,能够应用于临床.     

哈尔滨地区青年正常(牙合)颅面三维CT测量

目的:建立哈尔滨地区正常恒牙(牙合)颅面三维CT测量项目和参考值范围.方法:采用螺旋CT和AW4.2工作站对58 例哈尔滨地区17~25 岁正常恒牙(牙合)青年颅颌面硬组织重建测量,并进行统计分析.结果:角度测量项目基本无性别差异,大多数线距测量值男性组显著大于女性组.△GoL-S-GoR为近似等边三角形.面前部及颅底项目比值无性别差异,N-ANS∶ ANS-Me∶ N-Me约为0.45∶ 0.56∶ 1,SN∶ Ba-S∶ N-Ba约为0.57∶ 0.52∶ 1.左右测量项目间无统计学差异,下颌非对称率平均值(2.52±1.42)%.结论:建立了哈尔滨地区成年人恒牙(牙合)三维CT颅颌面硬组织正常值数据库;线距测量有性别差异,男性较大;男女2 组间角度测量值及面部比率呈较高的一致性;△GoL-S-GoR是一理想的美学三角;该方法对面部不对称性畸形分析较为可靠.     

蒙古族正常成年人颅颌面硬组织的三维CT测量研究

目的研究蒙古族正常成年人颅颌面硬组织的三维头影测量正常值,为正颌外科提供临床诊断、治疗计划及手术方案制定的数字依据。方法对48名符合正常标准的三代蒙古族后裔成年人进行颅颌面螺旋CT薄层扫描,用三维软件重建颅颌面硬组织三维图像,在屏幕上定点测量37项线距和19项角度。结果获得了蒙古族正常成年人颅颌面硬组织双螺旋CT三维头影测量正常值。结论①蒙古族正常成年人颅颌面硬组织的差异主要体现在骨骼大小上,而在骨骼轮廓和比例关系上差异较小,蒙古族女性的下颌开张度大于男性,而男性较女性面部前凸。②蒙古族正常成年人颅颌面硬组织结构左右也存在着一定程度的属于正常形态变异的不对称现象。③蒙古族正常成年人颅颌面硬组织形态具有明显的性别差异及种族特点,在正颌外科的临床诊断、治疗计划、手术方案的制定及术后面形预测应参考蒙古族自身的正常值。     

蒙古族正常(牙合)成年人颅颌面硬组织的三维CT测量研究

目的研究蒙古族正常耠成年人颅颌面硬组织的三维头影测量正常值，为正颌外科提供临床诊断、治疗计划及手术方案制定的数字依据。方法对48名符合正常铪标准的三代蒙古族后裔成年人进行颅颌面螺旋CT薄层扫描，用三维软件重建颅颌面硬组织三维图像，在屏幕上定点测量37项线距和19项角度。结果获得了蒙古族正常耠成年人颅颌面硬组织双螺旋CT三维头影测量正常值。结论①蒙古族正常耠成年人颅颌面硬组织的差异主要体现在骨骼大小上，而在骨骼轮廓和比例关系上差异较小，蒙古族女性的下颌开张度大于男性，而男性较女性面部前凸。②蒙古族正常耠成年人颅颌面硬组织结构左右也存在着一定程度的属于正常形态变异的不对称现象。③蒙古族正常耠成年人颅颌面硬组织形态具有明显的性别差异及种族特点，在正颌外科的临床诊断、治疗计划、手术方案的制定及术后面形预测应参考蒙古族自身的正常值。     

哈尔滨地区正常恒牙颅面三维CT测量研究

目的建立哈尔滨地区正常恒牙颅面三维CT测量项目和参考值范围。方法采用螺旋CT和AW4.2工作站对58例哈尔滨地区17~25岁正常恒牙青年颅颌面硬组织重建测量,并进行统计分析。结果角度测量项目基本无性别差异,绝大多数线距测量值男性组显著大于女性组;面前部及颅底项目比值无性别差异,N-ANS∶ANS-Me∶N-Me约为0.46∶0.56∶1,SN∶Ba-S∶N-Ba约为0.57∶0.52∶1;左右测量项目间无统计学差异;下颌非对称率<2.5%(2.4°或2.3 mm)。结论建立了哈尔滨地区成年人恒牙三维CT颅颌面硬组织正常值数据库。线距测量有性别差异,男性较大;男女两组间角度测量值及面部比率呈较高的一致性;GoL-S-GoR是一理想的美学三角;该方法对面部不对称性畸形分析较为可靠。     

新疆维族正常成人颅面硬组织结构的X线头影测量研究

目的:研究新疆维吾尔族正常成人颅面硬组织结构,建立其X线头影测量正常参考值,并探讨维族人与汉族人、白种人颅面结构的差异.方法:选择93例新疆维族正常成人(男43,女50),摄取标准定位头颅侧位X线片,描图、定点,图形数值化仪采集标志点,选择常用头影测量项目23项,运行自编软件,由计算机完成各项指标的测量,各项数据的性别差异采用t检验,与汉族人及白种人的差异采用方差分析及两两比较.结果:建立了新疆维族正常成人硬组织结构X线头影测量正常参考值,探讨了其性别特征与种族特征.结论:新疆维族男性颅底长、前后面高、面深度均大于女性.维族人颅面硬组织结构特征介于白种人与汉族人之间.     

颅面部螺旋CT三维线距测量的准确性评价

目的:研究颅面部螺旋CT三维线距测量与实测距离的一致性。方法:选择12个干燥头颅,采用GE公司16层螺旋CT常规扫描后,将头颅数据转至工作站,进行颅颌面三维重建。选择正畸常用的16个颅面骨性解剖标志点,分别使用DisplayTools测量工具和游标卡尺进行20个项目测量。采用SAS9.0统计软件包进行配对t检验,比较螺旋CT三维线距测量与实测距离的一致性。结果:螺旋CT三维线距测量与游标卡尺实测结果相比,P值范围为0.0995～0.9812,所有测量项目均无显著性差异。结论:螺旋CT体绘制图像颅面解剖标志点间线性距离与实测距离具有一致性,螺旋CT三维测量有望替代实际测量,用于头影测量分析。     

哈尔滨地区青年正常颅面三维CT测量

目的：建立哈尔滨地区正常恒牙颅面三维CT测量项目和参考值范围。方法：采用螺旋CT和AW4.2工作站对58例哈尔滨地区17-25岁正常恒牙青年颅颌面硬组织重建测量,并进行统计分析。结果：角度测量项目基本无性别差异,大多数线距测量值男性组显著大于女性组。△GoL-S-GoR为近似等边三角形。面前部及颅底项目比值无性别差异,N-ANS∶ANS-Me∶N-Me约为0.45∶0.56∶1,SN∶Ba-S∶N-Ba约为0.57∶0.52∶1。左右测量项目间无统计学差异,下颌非对称率平均值（2.52&#177;1.42）%。结论：建立了哈尔滨地区成年人恒牙三维CT颅颌面硬组织正常值数据库;线距测量有性别差异,男性较大;男女2组间角度测量值及面部比率呈较高的一致性;△GoL-S-GoR是一理想的美学三角;该方法对面部不对称性畸形分析较为可靠。     

哈尔滨地区正常恒牙(牙合)颅面三维CT测量研究

目的建立哈尔滨地区正常恒[牙合]颅面三维CT测量项目和参考值范围。方法采用螺旋CT和AW4.2工作站对58例哈尔滨地区17-25岁正常恒[牙合]青年颅颌面硬组织重建测量,并进行统计分析。结果角度测量项目基本无性别差异,绝大多数线距测量值男性组显著大于女性组;面前部及颅底项目比值无性别差异,N-ANS∶ANS-Me∶N-Me约为0.46∶0.56∶1,SN∶Ba-S∶N-Ba约为0.57∶0.52∶1;左右测量项目间无统计学差异;下颌非对称率〈2.5%（2.4&#176;或2.3 mm）。结论建立了哈尔滨地区成年人恒[牙合]三维CT颅颌面硬组织正常值数据库。线距测量有性别差异,男性较大;男女两组间角度测量值及面部比率呈较高的一致性;GoL-S-GoR是一理想的美学三角;该方法对面部不对称性畸形分析较为可靠。     

Clinical applications of 3-D CT and 3-D plastic model in the maxillo-facial region

We compared the usefulness of 3-D plastic models with that of 3-D CT images with regard to their applications in the field of maxillo-facial medicine. We also considered possibilities for wider clinical applications for both these methods. Five patients with the following conditions were involved in this study: hyperplasia of the mandibular condyle, 1; fracture of the maxilla and mandible, 1; coronoid hyperplasia, 2; and unilateral temporomandibular joint ankylosis with microgenia, 1. Stereolithographic models and 3-D CT images were made for each patient. CT and 3-D CT images were superior to plastic models with respect to their clinical diagnostic value. Furthermore they provided more precise information about the surface and inner structures of the jaws. 3-D plastic models made it possible to do close observation of the complex anatomical relationship of the region which were easily overlooked on axial CT images and even on 3-D CT images. The 3-D plastic models were useful for simulated surgery in all these cases. In the cases with bilateral coronold process hyperplasia, the plastic model well clarified the direct functional cause of the patients trismus. The analysis on plastic models suggested that the abnormal contact of the coronold process with the deformed surrounding anatomical structures might cause trismus and elongation of the process. We believe that plastic models can be applied to other dental fields such as dental implantology, prosthodontics and measuring for 3-D cephalometry.     

A new method of 3-D cephalometry Part I: the anatomic Cartesian 3-D reference system

The purpose of this study was to present a new innovative three-dimensional (3-D) cephalometric method. Part I deals with the set-up and validation of a voxel-based semi-automatic 3-D cephalometric reference system. The CT data (DICOM 3.0 files) of 20 control patients with normal skeletal relationships were used for this study. To investigate accuracy and reliability of the 3-D cephalometric reference system (Maxilimtrade mark, version 1.3.0) a total of 42 (14 horizontal, 14 vertical and 14 transversal) orthogonal measurements were performed on each patient twice by each of two investigators. The intra-observer measurement error was less then 0.88 mm, 0.76 mm and 0.84 mm for horizontal, vertical and transversal orthogonal measurements, respectively. The inter-observer measurement error was less as 0.78 mm, 0.86 mm and 1.26 mm for horizontal, vertical and transversal orthogonal measurements, respectively. Squared correlation coefficients showed a high intra-observer and inter-observer reliability. The presented 3-D cephalometric reference system proved to be accurate and reliable and can therefore be used for 3-D cephalometric hard and soft tissue analysis.     

3-D analysis of dislocation in zygoma fractures

ObjectiveWhen fractured, zygomas rotate and dislocate. The present study quantitatively elucidates the pattern of the rotation.Methods50 patients with tri-pod-type zygoma fractures were involved in this study. After defining a 3-dimensional coordinate system – consisting of the M–L axis (the axis directed from the medial to lateral side of the skull), I–S axis (directed from the inferior to superior side), and P–A axis (directed from the posterior to anterior side), the degree with which the fractured zygomas rotated around each of these axes was measured using 3-dimensional graphic software. Thereafter, the tendency of the rotation was compared between the three rotational axes.ResultsRotation around the I–S axis was the most frequent with a 96% incidence, followed by a substantial margin by rotation around the M–L axis with a 26% incidence; rotation around the P–A axis was rare, with an incidence of 10%. Furthermore, the degree of P–A axis rotation was minor compared to I–S and M–L axis rotations.ConclusionThe main factor of zygoma dislocation in zygoma fracture is rotation around the I–S axis. This finding is helpful for effective performance to reposition fractured zygomas.     

牙列缺损的计算机三维建模

目的 建立牙列缺损的计算机三维模型。方法 采用表面绘制法,依据CT扫描头颅骨标本获得的二维断层图像数据在3D Studio Max中沿牙体长轴放样、微调并赋以材质,得到牙列缺损的计算机三维模型。结果 能在计算机中方便快速地模拟任意类型的牙列缺损,并可全方位地旋转、放大和缩小。结论 提供了一种牙列缺损三维建模的新方法,有利于三维义齿专家系统的开发和计算机辅助教学。     

3-D COSMOS: a new 3-D model based computerised operation simulation and navigation system.

A new three-dimensional (3-D) model based system for preoperative planning, simulating the operation and transfer of the operation from 3-D model to patient (navigation) is to be introduced. A computer controlled digitizer with specially designed software enables 3-D measurement and symmetry analysis on the 3-D model with a precision better than 0.01 mm (SD: 0.05 mm, range: -0.2 to +0.04 mm). Translocations of the jaws during simulation are electronically registered with 6D-position sensors and displayed graphically and numerically on the PC screen (measurement accuracy 0.01 mm, 0.002 degrees). A precise transfer of positional data from the model to the patient in the operating theater is necessary if 3-D model operations are to be made. The position transfer (navigation) system to be introduced depends on a neurosurgical headframe on the patient, enabling an easy and three-dimensionally precise transfer of the planned jaw position to the patient. The three-dimensional precision of the positional transfer is 0.05 mm (SD: 0.144 mm, range: -0.36 to +0.69 mm). This new method allows for the first time exact three-dimensional simulation of operation and precise transfer to the patient. Especially in the case of asymmetric malformation and complex dysgnathia, the new method facilitates optimal symmetric and aesthetic results.     

2-D and 3-D reconstructions of spiral computed tomography in localization of the inferior alveolar canal for dental implants

OBJECTIVE: The purpose of this study was to compare and validate the accuracy of measurements on 2-dimensional and 3-dimensional reconstructions from spiral computed tomography in localization of the inferior alveolar canal. STUDY DESIGN: Four edentulous human cadaver heads with intact mandibles were imaged in a spiral computed tomography scanner. The data were transferred to a networked computer workstation to generate 2-dimensional orthoradially reformatted and 3-dimensional volumetric images. Linear measurements of the images were made from the superior border of the inferior alveolar canal to the alveolar crest. The specimens were then dissected at corresponding locations, and physical measurements were made. RESULTS: There were no statistically significant differences between the 2-dimensional computed tomography measurements and the physical measurements or between the 3-dimensional computed tomography measurements and the physical measurements. However, we did find a statistically significant difference between the 2-dimensional and 3-dimensional computed tomography measurements. CONCLUSIONS: 2-dimensional and 3-dimensional computed tomography images allow accurate measurements for localization of the inferior alveolar canal.