鼻缺损修复CAD/CAM系统的开发——汉族人三维标准外鼻形态数据库的建立

目的:提供具有汉族人群标准数值的多种形态的三维数字外鼻,建立标准鼻型数据库,以满足鼻缺损患者赝复的需要。方法:采集30岁以下男女的6种类型共12个外鼻,取模,灌超硬石膏模型,然后通过三维激光扫描测量系统转换为.asc格式的三维数字化模型。将数字模型按照解剖形态分为6区构面,添加颜色进行可视化显示,以.igs格式保存。在SUrFACER10.5软件中重现各鼻.asc格式的三维图形,测量鼻长、鼻宽,然后用张万洲1011个汉族成人鼻鼻长、鼻宽的活体测量结果,取代.asc和.igs格式各鼻鼻长、鼻宽的测量结果,将数据存盘。结果:得到12个大小一致的标准外鼻的点云构型文件和曲面构型文件以及各自的二维图片,分别按照6类理想鼻型以树状结构存盘。结论:构建了三维标准外鼻形态数据库,为鼻缺损修复CAD/CAM系统的应用奠定了基础。     

牙颌模型三维激光扫描系统可靠性研究及与手工测量的比较

目的 对牙颌模型三维激光扫描系统的可靠性进行研究,并为其临床应用提供科学依据。方法 利用Ｄ．０１－Ｌ－３Ｄ ＳＣＡＮＮＥＲ系统扫描和测量了３０例基本正常石膏模型。采用三种方法检验了牙颌模型三维激光扫描系统的可靠性,并与手工测量进行了比较。结果 可靠性一个方法的结果显示无显著性差异;与手工测量的比较无显著性差异,但牙颌模型三维激光扫描系统具有一些手工测量所无法达到的功能。结论 牙颌模型三维激光扫描系     

三维外鼻CAD/CAM系统数字模型形态调整的研究

目的开发三维外鼻数字模型形态调整功能,以满足鼻缺损患者个性化修复的要求。方法利用汉族人标准外鼻形态三维数据库中曲面数字模型,按照外鼻美学特征,对局部形态进行计算机辅助调整,并将调整后的外鼻通过快速成型方法制作出树脂模型。结果实现了外鼻鼻翼鼻孔区、鼻尖鼻小柱区、鼻根鼻梁形态、鼻的长度与鼻梁高度等局部形态调整,并验证了形态调整的可行性。结论三维外鼻CAD/CAM系统数字模型形态调整为鼻赝复体达到自动化、个性化的仿真修复奠定了基础。     

三种测量技术应用于口腔正畸模型测量中的比较研究

目的 对应用于正畸治疗中的三种正畸模型测量技术进行可靠性对比研究,并分析三种方法的差异.方法 采用手工直接测量、数码近摄测量、三维激光扫描测量三种方法对100副牙颌模型上每个牙的牙冠近远中径分别测量,并将三种测量值进行统计学分析.结果 三种测量技术之间无显著性差异;但三维激光扫描测量方法具有其他两种测量方法所不具有的优点.结论 三种测量技术都可进行准确的模型测量,三维激光扫描技术因其具有的优点而有广泛的临床应用前景.     

国产三维颅颌面数据激光测量系统可靠性和稳定性研究

目的　研究国内首台由卫生部口腔医学计算机应用工程技术研究中心与中国科学院自动化所共同研制开发的三维颅颌面数据激光测量与重建系统的可靠性和稳定性。方法　对同一重建图像间隔 3周的 2次激光测量结果、同一石膏头像间隔 3周的 2次激光扫描重建图像测量结果、同一石膏头像的手工与激光扫描测量结果进行配对T检验。结果　同一重建图像间隔 3周的前后 2次测量结果 ,差异无显著性 (P >0 0 5) ;同一石膏头像间隔 3周的前后 2次激光扫描重建图像测量结果 ,差异无显著性 (P >0 0 5) ;同一石膏头像的手工与激光扫描测量结果 ,差异无显著性 (P >0 0 5)。结论　作者对重建后图像上点的辨认是可靠的 ,三维颅颌面数据激光扫描测量与重建系统的可靠性和稳定性好 ,能够对以往难以测量的内容进行测量 ,可以初步应用于临床研究     

国产三维颅颌面数据激光测量系统的可靠性和稳定性研究

目的 研究国内首台由卫生部口腔医学计算机应用工程技术研究中心与中国科学院自动化所共同研制开发的三维颅颌面数据激光测量与重建系统的可靠性和稳定性。方法 对同一重建图像间隔3周的2次激光测量结果、同一石膏头像间隔3周的2次激光扫描重建图像测量结果、同一石膏头像的手工与激光扫描结果进行配对T检验。结果 同一重建图像间隔3周的前后2次测量结果，差异无显著性（P＞0.05)；同一石膏头像间隔3周的前后2次激光扫描重建图像测量结果，差异无显著性（P＞0.05)；同一石膏头像的手工与激光扫描测量结果，差异无显著性（P＞0.05)。结论 作者对重建后图像上点的辨认是可靠的，三维颅颌面数据激光扫描测量与重建系统的可靠性和稳定性好，能够对以往难以测量的内容进行测量，可以初步应用于临床研究。     

非接触式牙颌模型三维激光测量分析系统的研制

目的　研制开发非接触式牙颌模型激光扫描三维数字化系统。方法　用两个步进电机构成牙颌模型旋转与平移的合成运动 ,由一个半导体激光器和两个线阵列 (chargecoupleddevice ,CCD)摄像机获得模型表面各点的三维座标。采用VisualC 编程 ,在Windows环境下运行 ,完成扫描控制、三维图形重建及测量。结果　该系统测量范围为 70mm× 70mm× 70mm ,测量精度为 0 .0 1mm ,平均测量误差 <0 .1mm ,单颌模型扫描时间 <2 5分钟。用本系统与手工方法对 15副正常颌模型进行测量比较 ,二者间差异无显著性 (P >0 .0 5 )。结论　该系统具有精确、简单、高效、测量内容丰富、完整、直观等优点。还开发出一些以往靠手工方法无法实现的新功能。     

光学测量系统在面部外形测量中的应用研究

目的 研究面部三维光学测量系统在面部外形重建和测量中的实用性和可靠性。方法 利用自行研制的面部三维光学测量系统扫描45名正常人面形，结合Geomagic studio软件反求重建面部外形。比较面部内眦间距、鼻长、鼻宽、鼻高、鼻深等的反求测量结果与手工测量结果间的差异。结果 基于面部三维光学测量系统结合反求软件直接重建了45名正常人的面部三维外形，面部测量项目的 反求测量结果与手工测量结果在统计学上无明显差异（P>0.05）。结论 面部三维光学测量系统在面部外形采集、反求重建、三维测量中具有较高的可靠性和较好的实用性。     

激光扫描法建立三维数字化牙颌模型的准确性和可靠性评价

目的 研究应用激光扫描法建立三维数字化牙颌模型的准确性和可靠性评价。方法 选择正畸治疗患者的石膏模型24 副,采用激光扫描法对石膏模型进行扫描,建立三维数字化牙颌模型,并对其牙冠宽度、牙冠高度、牙弓宽度和牙弓长度进行测量,与手工测得的结果进行比较分析。结果 石膏模型和数字化模型所有测量项目的一致性相关系数中,除双侧上颌第一前磨牙颊尖顶之间的距离(CCC=0.6307)和上颌中切牙近中接触点到右侧第一磨牙远中接触点的距离2 项测量指标结果(CCC=0.6571)良好外,其余指标的一致性都比较接近(CCC>0.7)。所有测量项目的均数差在0.017~0.862mm 之间,平均为0.104mm,D%﹤5%,部分指标存在统计学差异,但不具有临床意义。结论 基于激光扫描技术重建的三维数字化牙颌模型中,牙冠宽度和牙冠高度的准确性高,牙弓长度其次,牙弓宽度的准确性较低。     

唇腭裂患者牙槽嵴数字化模型建立及分析的初步探讨

目的 通过三维激光扫描建立唇腭裂患者牙槽嵴的数字化模型，为唇腭裂患者的模型分析建立科学方法。方法 唇裂修复术前于全麻状态下对1例右侧完全性唇腭裂患者的上颌无牙颌制取模型，用激光扫描仪扫描，通过计算机逆向工程软件进行模型重建。结果 此法可在重建模型上设定测量参考点9个，并可测出各标志点间的距离；模型可切割后测量和计算。结论 激光扫描三维分析方法是分析唇腭裂患者牙槽嵴形态及方向改变的一种理想方法，应用此模型可量化分析唇腭裂患者随生长发育而变化的上颌牙槽嵴形态。     

A comparison study of different facial soft tissue analysis methods

ObjectivesThe purpose of this study was to evaluate several different facial soft tissue measurement methods.Materials and methodsAfter marking 15 landmarks in the facial area of 12 mannequin heads of different sizes and shapes, facial soft tissue measurements were performed by the following 5 methods: Direct anthropometry, Digitizer, 3D CT, 3D scanner, and DI3D system. With these measurement methods, 10 measurement values representing the facial width, height, and depth were determined twice with a one week interval by one examiner. These data were analyzed with the SPSS program.ResultsThe position created based on multi-dimensional scaling showed that direct anthropometry, 3D CT, digitizer, 3D scanner demonstrated relatively similar values, while the DI3D system showed slightly different values. All 5 methods demonstrated good accuracy and had a high coefficient of reliability (>0.92) and a low technical error (<0.9 mm). The measured value of the distance between the right and left medial canthus obtained by using the DI3D system was statistically significantly different from that obtained by using the digital caliper, digitizer and laser scanner (p < 0.05), but the other measured values were not significantly different. On evaluating the reproducibility of measurement methods, two measurement values (Ls–Li, G–Pg) obtained by using direct anthropometry, one measurement value (N′–Prn) obtained by using the digitizer, and four measurement values (En_Rt–En_Lt, Ala_Rt–Ala_Lt, Ch_Rt–Ch_Lt, Sn–Pg) obtained by using the DI3D system, were statistically significantly different. However, the mean measurement error in every measurement method was low (<0.7 mm). All measurement values obtained by using the 3D CT and 3D scanner did not show any statistically significant difference.ConclusionThe results of this study show that all 3D facial soft tissue analysis methods demonstrate favorable accuracy and reproducibility, and hence they can be used in clinical practice and research studies.     

Reliability of a 3D surface laser scanner for orthodontic applications.

A device for recreating three-dimensional (3D) objects on a computer is the surface laser scanner. By triangulating distances between the reflecting laser beam and the scanned surface, the surface laser scanner can detect not only an object's length and width but also its depth. The scanner's ease of use has opened various possibilities in laboratory research and clinical investigation. We assessed the reliability of generating 3D object reconstructions using the Minolta Vivid700 3D surface laser scanner (Minolta USA, Ramsey, NJ). Accuracy and reproducibility were tested on a geometrical calibrated cylinder, a dental study model, and a plaster facial model. Tests were conducted at varying distances between the object and the scanner. It was found that (1) in the calibrated cylinder tests, spatial distance measurement was accurate to 0.5 mm (+/- 0.1 mm) in the vertical dimension and 0.3 mm (+/- 0.3 mm) in the horizontal dimension; (2) in the study model test, molar width was accurate to 0.2 mm (+/- 0.1 mm, P >.05), and palatal vault depth could be measured to 0.7 mm (+/- 0.2 mm, P > 0.05); and (3) for the facial model, an accuracy of 1.9 +/- 0.8 mm was obtained. The findings suggest that the surface laser scanner has great research potential because of its accuracy and ease of use. Treatment changes, growth, surgical simulations, and many other orthodontic applications can be approached 3-dimensionally with this device.     

The influence of the segmentation process on 3D measurements from cone beam computed tomography-derived surface models

To compare the accuracy of linear and angular measurements between cephalometric and anatomic landmarks on surface models derived from 3D cone beam computed tomography (CBCT) with two different segmentation protocols was the aim of this study. CBCT scans were made of cadaver heads and 3D surface models were created of the mandible using two different segmentation protocols. A high-resolution laser surface scanner was used to make a 3D model of the macerated mandibles. Twenty linear measurements at 15 anatomic and cephalometric landmarks between the laser surface scan and the 3D models generated from the two segmentation protocols (commercial segmentation (CS) and doctor’s segmentation (DS) groups) were measured. The interobserver agreement for all the measurements of the all three techniques was excellent (intraclass correlation coefficient 0.97–1.00). The results are for both groups very accurate, but only for the measurements on the condyle and lingual part of the mandible, the measurements in the CS group is slightly more accurate than the DS group. 3D surface models produced by CBCT are very accurate but slightly inferior to reality when threshold-based methods are used. Differences in the segmentation process resulted in significant clinical differences between the measurements. Care has to be taken when drawing conclusions from measurements and comparisons made from different segmentations, especially at the condylar region and the lingual side of the mandible.     

一种新型三维牙颌模型激光扫描仪可靠性对比研究

目的：检验新型三维牙颌模型激光扫描仪的可靠性。方法：分次利用不同方法，扫描和测量8副牙列石膏模型上的解剖标志点，对测量结果进行统计分析。结果：同一激光扫描两次定点的线距和角度的测量结果之间差异没有显著性；两次激光扫描分别定点测量的线距和角度结果之间差异也没有显著性；激光扫描定点测定和三维测量仪分别测得的线距和角度结果之间差异也没有统计学意义。结论：D.0.2-L-3D SCANNER激光扫描仪具有较高的精度，较好的可靠性，扫描速度快，扫描盲区少，该系统可以用于以后修复体CAD/CAM系统光学印模的制取。     

牙弓后段不同位置基骨宽度分析的研究

目的 比较牙弓后段不同位置的基骨宽度.方法 选取安氏Ⅱ类、Ⅲ类患者各30例.使用3Shape扫描仪扫描石膏模型获得数字化模型.原始数字化模型作为对照组T0;利用3Shape软件模拟牙移动,使第一磨牙达到中性关系,获得数字化模型作为实验组(T1、T2、T3).应用牙槽嵴中心宽度分析法对实验组与对照组数字化模型进行宽度测量...     

Validity and reliability of craniofacial anthropometric measurement of 3D digital photogrammetric images

BACKGROUND: Direct anthropometry performed during a patient examination is the standard technique for quantifying craniofacial dysmorphology, as well as for surgical planning and outcome assessment. Several new technologies have been designed to computerize anthropometric measurements, including three-dimensional (3D) digital photogrammetry. These digital systems have the advantage of acquiring patient craniofacial surface images quickly and noninvasively. Before morphometry using digital photogrammetry can be applied in clinical and research practice, it must be assessed against direct anthropometry. OBJECTIVE: To evaluate the validity and reliability of facial anthropometric linear distances imaged by 3D digital photogrammetry with respect to direct anthropometry. DESIGN, SETTING, PARTICIPANTS, MEASURES: Standard craniofacial distances were directly measured twice on 20 normal adult volunteers. Craniofacial surfaces were also imaged using the 3dMDface digital photogrammetry system, and distances were digitally measured twice for each subject. Validity measures of accuracy and bias (for direct versus digital measurements) and reproducibility measures of precision and test-retest reliability (for repeated sets of digital measurements) were computed. RESULTS: Seventeen of the 18 direct measurements correlated highly with digital values (mean r = 0.88). The correlation for one measurement (upper prolabial width) was not statistically significant. The overall precision of all 17 digital measurements was less than 1 mm, and the reliability was high (mean r = 0.91). CONCLUSIONS: Craniofacial anthropometry using the 3dMDface System is valid and reliable. Digital measurements of upper prolabial width may require direct marking, prior to imaging, to improve landmark identification.     

3D volume-ablation rate and thermal side effects with the Er:YAG and Nd:YAG laser.

OBJECTIVES: The aim of this investigation was to determine the influence of a variety of parameters on the effectiveness of hard substance ablation and the thermal side effects when using Er:YAG laser (Key I and II, KaVo) and Nd:YAG laser (SunLase 800, Sunrise Technologies/Orbis). METHODS: For this study, ablation and temperature measurements were carried out on 170 dentin slices and 170 extracted teeth via computer-controlled cavity preparation. The Er:YAG laser settings varied from 250-400 mJ/pulse, 3-15 pps and 20-180 s processing time, and in the case of the Nd:YAG laser from 83-100 mJ/pulse, 10-20 pps, and 20-260 s processing time. The ablation rate was measured volumetrically via a 3D sensor. Temperatures were measured for each setting both on the dentin slice and in the pulp of the extracted teeth. The results were analyzed using a t-test for independent samples and a one-way ANOVA (Bonferroni). Also a liner regression analysis was done using Pearson's coefficient. RESULTS: The results show that with the Er:YAG laser, in combination with water-spray cooling, an effective 3D ablation rate (up to 0.017 mm3/pulse = 50 microns linear) can be achieved without raising the temperature of the surrounding tissue. In the case of the Nd:YAG laser, no measurable ablation rate was evident without conditioning of the dentin surface and, in the case of conditioning with black ink, a low ablation rate (0.00004 mm3/pulse = linear 0.2 micron/pulse) was found. SIGNIFICANCE: In contrast to the Er:YAG laser, it is apparent, that with the Nd:YAG laser from a total energy of 80 J onwards, the rise in temperature in the pulp is above 8 degrees C. For that reason, the use of the Nd:YAG laser at higher total energies is not recommended. The temperature rise with the Nd:YAG laser is dependent on the direction of the dentin tubuli. Dentin tubuli running parallel to the surface prevent significant heat penetration, whereas those running in a transverse direction to the surface (= parallel to the laser beam) support the penetration of heat. This finding supports the light-propagating theory for spreading effects of laser beams in dentin.     

Comparison of the color of natural teeth measured by a colorimeter and Shade Vision System.

OBJECTIVES: The objectives were to measure the difference in the color and color parameters of natural teeth measured by a tristimulus colorimeter (CM, used as a reference) and Shade Vision System (SV), and to determine the influence of color parameters on the color difference between the values measured by two instruments. METHOD: Color of 12 maxillary and mandibular anterior teeth was measured by CM and SV for 47 volunteers (number of teeth=564). Color parameters such as CIE L*, a* and b* values, chroma and hue angle measured by two instruments were compared. Chroma was calculated as C*ab=(a*2 = b*2)1/2, and hue angle was calculated as h degrees =arctan(b*/a*). The influence of color parameters measured by CM on the color difference (DeltaE*(ab)) between the values measured by two instruments was analyzed with multiple regression analysis (alpha=0.01). RESULTS: Mean DeltaE*(ab) value between the values measured by two instruments was 21.7 (+/-3.7), and the mean difference in lightness (CIE L*) and chroma was 16.2 (+/-3.9) and 13.2 (+/-3.0), respectively. Difference in hue angle was high as 132.7 (+/-53.3) degrees . Except for the hue angle, all the color parameters showed significant correlations and the coefficient of determination (r(2)) was in the range of 0.089-0.478. Based on multiple regression analysis, the standardized partial correlation coefficient (beta) of the included predictors for the color difference was -0.710 for CIE L* and -0.300 for C*(ab) (p<0.01). CONCLUSION: All the color parameters showed significant but weak correlations except for hue angle. When lightness and chroma of teeth were high, color difference between the values measured by two instruments was small. Clinical accuracy of two instruments should be investigated further.     

Survivin mRNA、Caspase-3mRNA在舌鳞癌中的表达及相关性

目的:检测舌鳞癌组织中凋亡抑制基因Survivin mRNA及Caspase-3 mRNA的表达,探讨其在舌鳞状细胞癌中的意义及相关性。方法:应用原位杂交方法检测10例正常舌黏膜、45例舌鳞状细胞癌标本中Survivin mRNA及Caspase-3 mRNA的表达情况。采用SPSS13.0软件包进行χ2检验及Fisher精确概率法检验,指标间关系采用Spearman等级相关分析。结果:舌鳞癌标本中Survivin mRNA阳性表达率为55.6%,正常对照组全部为阴性,两组差异显著(P<0.01);舌鳞癌标本中Caspase-3 mRNA阳性表达率为42.2%,明显低于正常对照组的80.0%(P<0.05);Survivin mRNA高表达及Caspase-3 mRNA低表达与舌鳞癌组织学分级、颈淋巴结转移相关(P<0.05);与TNM分期密切相关(P<0.01);经Spearman等级相关分析,两者之间呈显著负相关,r=-0.412,P=0.005。结论:在舌鳞癌中,Survivin mRNA参与了抑制Caspase-3m RNA的表达,且这种抑制作用与肿瘤的发生、发展相关。     

Slumping during sculpturing of composite materials

OBJECTIVES: This study investigated the slumping characteristics of four composite materials during sculpturing prior to their polymerization. METHODS: Four different composite materials were used to measure shape deformation due to slumping. Silicon impressions of the occlusal plane of three different molars were used as a mould for the composite samples. The surface of the samples was digitized with a laser scanner (400 slices, lateral resolution: 25 microm). Scans were made after 1-4 min. The 3D data sets were numerically superimposed with matching software and differences were calculated relative to the baseline measurement. RESULTS: The amount of surface deformation increases with increasing observation time. The average coefficient of variation was 0.2. The largest mean amount of slumping was observed for ELS with tooth mould 1 (150.0 microm), and for Clearfil Majesty with tooth mould 2 (98.3 microm) and mould 3 (42.8 microm). Miris 2 Dentin and Synergy D6 Enamel were rather similar and seem to exhibit little deformation. The slump flow of ELS and Clearfil Majesty was up to 400% higher than the formers. The deformation could be sorted in the following order "mould 3"<"mould 2"<"mould 1" for all materials and all observation time. There was a significant influence (p<0.05) of the three factors, time, mould and composite type (ANOVA). SIGNIFICANCE: This specific method provides a reproducible approach for the assessment of the handling characteristics of composite materials. The results can identify slumping differences and assist in collecting information about the feasibility of a material for certain indications.