【作者】 刘东旭；

【导师】 王春玲；

【作者基本信息】 山东大学 ， 口腔临床医学， 2007， 博士

【摘要】 第一部分螺旋CT体绘制颅面部图像线距测量的准确性评价目的人体测量学中颅颌面关系为三维空间结构关系，颅颌面的畸形常表现为三维空间结构的异常，现代口腔正畸临床诊断及治疗技术的发展，需要人们对颅颌面的三维空间结构关系做出准确的评价，而目前最常用的评价方法头颅侧位片和正位片，只能反映二维结构的情况，不能反映实际的位置关系，而且存在着影像学方面的放大及失真的问题，螺旋CT的体绘制图像为评估颅颌面关系的测量提供了一种三维方法，本研究的目的是评价颅面部螺旋CT体绘制图像线距测量与实测距离的一致性，并计算其精密度和准确度。材料与方法选择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，确定正畸常用的18个颅面骨性解剖标志点，测量者为临床经验丰富的同一位正畸医生，分别使用Display Tools测量工具和游标卡尺测量21个测量项目。间隔二周进行下一次测量，共测量四次。采用SAS9.0统计软件包进行配对t检验，比较螺旋CT体绘制线距测量与实测距离的一致性。计算三维体绘制图像线性距离的精密度和准确度。结果1．螺旋CT体绘制颅面部图像线距测量与游标卡尺实际测量结果相比，所有测量项目均无统计学差异；2．体绘制颅面部图像测量平均精密度和准确度分别是0.94％(0.25～2.76％)和0.24％(-0.76～1.73％)，而实际测量方法的精密度为0.81％(0.20～2.02％)；体绘制图像与实测法测量值的差值平均为0.20mm(-0.44～1.00mm)。结论螺旋CT体绘制图像颅面解剖标志点间线性距离与实际测量距离具有一致性，并且具有较高的精密度和准确度。螺旋CT三维测量可作为一种非介入方法，替代实际测量应用于口腔医学临床及研究。第二部分成人种植体支抗不同植入高度及方向时上下颌皮质骨厚度的束状CT研究目的第一磨牙与第二双尖牙颊侧牙槽骨为切牙后退和压低磨牙的最佳微型支抗种植体置入部位，本研究目的是评价该部位不同植入高度、不同植入方向时上下颌皮质骨厚度，为临床上选择适宜的植入高度提供依据。材料与方法成人患者22例，男女各11例，年龄20—43岁。日本森田束状CT机拍摄上下颌牙弓后段位置，采用i view软件测量第一磨牙与第二双尖牙之间牙槽嵴顶下1mm-8mm植入点与矢状面呈90度、30度、45度的颊侧皮质骨厚度及皮质骨厚度最小值与植入角度关系。与矢状面呈90度、30度、45度三组间比较，8个植入位置组间比较采用SAS9.0软件中配伍组设计的两因素方差分析以及最小显著差异法(least significant difference LSD法)作各组间两两比较。结果种植体呈90度植入，上颌第一磨牙与第二双尖牙间颊侧皮质骨厚度的均值在最靠近和最远离CEJ的地方最厚，中间最薄。下颌第一磨牙与第二双尖牙间颊侧皮质骨厚度从牙槽顶下至根尖水平逐渐增厚；如果种植体与矢状面呈30度或45度植入，除上颌牙槽顶1mm植入皮质骨厚度变小外，上下颌其它部位颊侧皮质骨厚度牙槽顶下至根尖水平逐渐增厚，上下颌第一磨牙及第二双尖牙间植入时与矢状面呈30度及45度斜行植入的颊侧皮质骨厚度较90度平均值分别增加2倍和1.4倍；从厚度最小值与植入角度测量数据看，上颌牙槽顶下1mm处与矢状面呈39度植入时皮质骨厚度最小，从2-6mm处与矢状面呈71.23度(2mm)至108度(6mm)逐渐增加角度植入时皮质骨厚度最小，从7-8mm处与矢状面约呈100度植入时皮质骨厚度最小。下颌牙槽顶下1mm处与矢状面呈74度植入时皮质骨厚度最小，其它部位约90度左右植入时皮质骨厚度最小。结论微型支抗种植体植入高度及方向与骨皮质接触厚度与有关，适宜的植入高度应具有一定皮质骨厚度且在附着龈处。除上颌牙槽顶1mm处与矢状面呈90度植入种植体可增加皮质骨厚度外，与矢状面呈30度斜行植入是临床适宜的角度。第三部分正常(牙合)不同生长型下颌后牙区牙倾斜度、牙槽骨形态学的CT研究目的生长型是正畸治疗中一个重要的考虑因素，这主要因为它影响支抗系统的选择、颌面结构的生长预测、矫治的目标的确定以及咬合力和咀嚼肌功能。本研究的目的是评价正常(牙合)生长型与下颌后牙区牙倾斜度、牙槽骨倾斜度、下颌骨高度、宽度及皮质骨的关系。材料与方法个别正常(牙合)成人16例，男女各8例，年龄23—41岁。采用美国GE公司16层螺旋CT(General Electric，GE，Light Speed plus，2004)进行扫描，建立头颅以及上下颌骨及牙弓的三维CT数字图像，采用软件Volume viewer software(Voxtool3.0.64q)测量上下面高比例，FMA(下颌平面和眶耳平面所成的夹角)，并根据测量结果将研究对象分为两组。测量下颌后牙区牙倾斜度、牙槽骨倾斜度、下颌骨高度、宽度及皮质骨厚度，采用SAS9.0统计软件包将两组数值进行t检验，评价正常(牙合)生长型与下颌后牙区牙倾斜度、牙槽骨倾斜度、下颌骨高度、宽度及皮质骨的关系。结果垂直生长型人群下颌第二磨牙和第一磨牙倾斜度的平均值分别是77.86±3.48度和80.23±2.10度，水平生长型的分别为82.85±4.30度和82.69±1.92度，按a=0.05，差别有统计学意义。两组人群下颌后牙区牙槽骨倾斜度、颊舌侧皮质骨厚度均值、最小均值及骨宽度接近；垂直生长型较水平生长型人群有较大的下颌骨高度。其他统计值显示差别无统计学意义。结论对于正常(牙合)人群，水平生长型的下颌磨牙较垂直生长型在颊舌向方向上更加直立；水平生长型与垂直生长型相比牙槽骨倾斜度相近，无明显更厚的下颌皮质骨及骨宽度；水平生长型比垂直生长型有明显小的下颌骨高度。更多还原

【Abstract】 Part IACCURACY ANALYSIS OF 3D-CT VOLUMERENDERING FOR CRANIOFACIL LINEARMEASUREMENTSObjective This study was designed to determine consistency of craniofacial measurements using Spiral computed tomography volume rendering by computer systems and sliding caliper, and evaluated the precision and accuracy of 3D rendered images craniofacial measurements by sixteen-slice helical CT, Methods The study population consisted of 12 cadaver heads that were examined with spiral CT. The archived CT data were transferred to a workstation, and 3D-CT volume rendered images were generated using computer graphics tools. Linear measurements (n=21), based upon conventional craniometric anatomical landmarks (n=18) were made, respectively by display tools and sliding caliper. The consistency between the two measurements was analyzed by paired t test. The precision and accuracy of 3D rendered images craniofacial measurements was calculated. Results The results demonstrated no statistically significant difference between imaging measurement and physical measurement; Precision and accuracy of 3D rendered images was 0.94% (range from 0.25-2.76%) and 0.24% (range from -0.76-1.73%) , respectively. Precision of direct measurements was 0.81% ( range from 0.20-2.02%). The difference of mean values between 3D rendered images and dry skull measurements was 0.20mm (range from-0.44-1.00 mm). Conclusions There is significant consistency between spiral CT measurement and physical measurement for craniofacial linear distance. 3D-CT volume rendering images using craniometric measurements can be used for clinic and studies instomatology.PART IICORTICAL BONE THICKNESS AND ANGULATIONSUSING LIMITED CONE BEAM COMPUTED TOMOGRAPHY FOR ADULT ORTHODONTICIMPLANTSObjective The buccal alveolar bone between the first molar and second premolar usually is the best microimplant area for retraction of the anterior teeth and for intrusion of the molars. The purpose of this study was to quantitatively evaluate the cortical bone thickness (CBT) and implant augulation in various locations in the maxilla and the mandible for adult orthodontics.Methods The sample consisted of 11 men and 11 women between 20 to 43 years of age. Limited cone beam computed tomographic images were reconstructed. Cortical bone thicknesses were measured at 3 angles (30°, 45°, and 90°) in the buccal regions from alveolar tip to the bottom of maxilla and mandible at the interval 1 mm. The minimum CBT and insertion angulations at the above areas were also assessed.Results At 90° insertion, upper cortical bone were thickest closest to and farthest from the cementoenamel junction (CEJ) and thinnest in the middle, lower CBT were increased from occlusion level to apical level except 1 mm site; At 30° and 45° insertion, CBT were increased gradually from alveolar tip except upper 1 mm site, and resulted in approximately 2, 1.4 times as much at30°, 45°compared with 90°. The minimum CBT and insertion angulations atvarious locations were different.Conclusions Surgical placement of microscrew for orthodontic anchorage inthe molar region requires consideration of the placement site and angle basedon anatomical characteristics. The safest location for placing miniscrew mightbe attached gingival. Oblique 30° insertion microimplant can increased CBTexcept upper 1mm site.Part IIITHE STUDY OF THE MANDIBULAR POSTERIORTEETH INCLINATIONS AND ALVEOLARMORPHOLOGY BETWEEN DIFFERENT GROWTHPATTERN OF NORMAL OCCLUSION BY CT SCANNINGObjective The purpose of the study is to evaluate relationship between the growth pattern of normal occlusion and posterior teeth inclinations, cortical bone thicknesses, mandibular heights and widths.Methods The subjects consist of 16 adults(8 male, 8 female)with individual normal occlusion, aged 23 to 41.For each subject, the three-dimensional digital radiograph of skull ,maxilla, mandible and dental arch will be available by 16-slice spiral computer tomography(CT, General Electric, GE, Light Speed plus, 2004)scanning. Then, the upper anterior face height (UAFH) and lower anterior face height (LAFH), FMA (inclination of the mandibular plane relative to Frankfort horizontal plane), and the inclinations of posterior teeth, cortical bone thicknesses and alveolar heights of the mandible are measured using Volume viewer software (Voxtool3.0.64q).The relationship among these structures could be available after the T-test of the results which obtained by the software.Results The average values of the inclination of the mandibular first molars and second molars for the vertical growth pattern subjects (the second group)are 77.86±3.48° and 80.23±2.10° respectively,the ones for the horizontal growth pattern subjects (the second group)are 82.85±4.30° and 82.69±1.92°.There is significant difference between the two groups(P<0.05). But no other significant difference is observed regarding buccal and lingual cortical bone thickness of the mandible between the two groups. The alveolar heights of the mandible for the vertical growth patterns are obviously greater than the horizontal ones.Conclusions The mandiblular molars in subjects with vertical growth patterns have a statistically significantly greater buccal inclination as compared with those with horizontal growth patterns. No statistically significant differences in the buccal and lingual cortical bone thickness of the mandible between the vertical growth patterns and the horizontal ones. The mandibular heights of the mandible for the vertical growth patterns are obviously greater than the horizontal ones.更多还原