三维数字化模型测量牙齿和牙弓的精确性研究

目的 通过与手工测量法比较,评估三维数字化法模型测量牙齿和牙弓的可靠性和精确性。方法 选择喀什地区维吾尔族成年人石膏模型150副,采用结构光扫描仪对石膏模型扫描获得三维图像后,运用Geomagic Studio 13.0分析软件进行分析和测量,分别测量牙冠高度、宽度、牙弓长度和宽度,与手工测量方法进行比较和分析。结果 虽然三维数字化法与手工法测得的牙冠宽度、高度和牙弓长度的部分数值具有统计学差异,但不具有临床意义,组内相关系数均>0.75。结论 结构光数字化模型的准确性好,在临床的诊断和治疗过程中可替代石膏模型。     

光栅投影技术及逆向工程在重建和测量牙颌数字化模型中的应用

目的 利用光栅投影技术采集数字化牙颌模型并用逆向工程分析测量模型特征,为建立正常牙列数字化模型数据库奠定基础。方法 在计算机控制下将光栅投影在正常牙颌模型上,通过多角度拍摄模型获得三维数据外形轮廓,利用逆向工程重建数字化模型和测量分析牙列形态特征,并与石膏模型测量结果进行对比分析。结果 重建的三维数字化模型结构清晰。数字化模型的两次测量结果无统计学差异（P>0.05）;数字化模型与石膏模型的测量指标中,牙冠长度和牙弓宽度均无统计学差异（P>0.05）,而牙冠宽度和牙弓长度均有统计学差异（P<0.05）。结论 通过光栅投影技术以及逆向工程重建数字化模型,可用于临床、科研中的牙颌模型测量,为建立正常牙颌数字化模型数据库提供科学方法。     

无托槽隐形矫治数字化模型及软件测量系统的准确性研究

目的 探讨国产无托槽隐形矫治客户端软件中基于工业CT重建的数字化模型及测量系统的准确性.方法 选择无托槽隐形矫治患者的初诊石膏模型20副,以及对应的无托槽隐形矫治公司提供的三维数字化模型20副.分别采用手工测量石膏模型,及软件测量系统测量数字化模型,测量项目包括牙冠宽度、临床牙冠高度、牙弓宽度、牙弓长度、(牙合)覆盖六项指标.采用组内相关系数(ICC)对重复测量信度进行评估;采用多变量假设检验(Hotelling T2检验)分析数字化模型及石膏模型的总体测量结果有无差异,并采用配对t检验分析两种模型测量方法在各测量指标上有无差异.结果 软件测量数字化模型的组内相关系数为0.958,优于手工测量石膏模型0.933.两种模型的总体测量结果无统计学差异(P＞0.05).在具体测量指标中牙冠宽度,牙弓长度,牙弓宽度无统计学差异(P＞0.05),而临床牙冠高度(P＜0.01)、覆(牙合)(P＜0.05)、覆盖(P＜0.05)有统计学差异.结论 无托槽隐形矫治软件测量系统中数字化模型及测量系统的准确性较高.     

运用激光扫描和三维重建技术测量蒙古族和汉族青少年上切牙的厚度及宽度

目的 测量并分析呼和浩特地区蒙古族和汉族人群上切牙牙冠厚度、宽度及宽厚比例的相关性。方法 筛选120副蒙古族和汉族青少年牙模型，对样本模型激光扫描并三维重建，测量上切牙厚度及宽度，采用配对t检验及回归分析。比较不同民族及性别宽度与厚度的差异，并分析宽厚比例及相关关系。结果 ①上切牙厚度男性>女性(P<0.05）。②上颌侧切牙厚度蒙古族>汉族(P<0.05）。③蒙古族上颌中切牙及侧切牙宽度男性>女性(P<0.05）；汉族上颌中切牙宽度男性>女性(P<0.05）。④上颌侧切牙牙冠宽度蒙古族>汉族(P<0.05）。⑤蒙古族和汉族上切牙牙冠厚度与宽度均具有线性关系。结论 上颌切牙的边缘嵴厚度及宽度存在性别及民族差异，牙冠厚度与宽度呈线性相关关系，同时建立了本地区蒙古族和汉族人群牙冠宽度及厚度的均数及标准差，为本地区患者临床正畸治疗中前牙美学及覆覆盖的设计提供理论参考。     

数字化三维牙颌模型测量系统的可靠性对比研究

目的 检验由我院和清华大学共同研制开发的建立于层析扫描技术基础上的牙颌模型数字化三维重建系统之测量软件的可靠性。方法 选择不同牙列期的患者20例，常规取印模并灌制成两副牙颌模型，组成为两个配对的样本；其中样本1保留为石膏模型，样本2由三维模型重建系统生成数字化的模型影像；由同一操作者间隔3周分别对石膏模型和数字模型的牙齿宽度、牙弓宽度和牙弓长度等测量项目进行两次测量。结果 数字化模型两次测量结果的差值经秩和检验表明无统计学差异；经两组样本各测量项目两次测量结果之差数的￡检验表明，牙弓宽度两次测量结果的差异在石膏模型和数字模型间无显著性；而牙弓长度和牙齿宽度两次测量结果的差异具有显著性。结论 三维重建系统可生成真实的数字化牙颌模型影象，系统测量软件能提供可靠的测量数据且其精确性明显优于石膏模型。     

利用锥形束CT和激光快速成型技术制作牙颌模型的可靠性分析

目的:分析建立上牙颌模型的锥形束CT和激光快速成型技术的可靠性。方法:收集20例正畸患者的牙颌石膏模型和锥形束CT数据,将CT数据重建成三维数字模型(即3-D模型),并应用激光快速成型技术加工出牙颌树脂模型(即RP模型)。对石膏、3-D和RP模型分别进行牙冠宽度、牙弓宽度、牙弓长度等测量,利用SPSS17.0软件包进行统计学分析。结果:3种模型之间,除牙弓宽度外,其余大部分指标具有显著差异(P<0.05);3-D模型值普遍小于石膏模型和RP模型(P<0.05);RP模型与石膏模型之间大部分指标不具有显著差异(P>0.05);RP、3-D模型与石膏模型之间的回归系数均具有显著差异(P<0.01),且前者普遍大于后者。结论:3种模型之间具有高度一致性,存在可为临床所接受的差异,提示3-D模型和RP模型具备替代石膏模型的可能性,从而节约存储空间,提高工作效率。     

新型3DSS-STD-Ⅱ结构光三维测量系统重建牙颌模型的可靠性对比研究

目的应用一种新型的三维测量系统3DSS- STD- Ⅱ对牙颌模型进行三维重建，评价该三维测量重建结果的可靠性，为口腔修复体计算机辅助设计奠定基础。方法利用新型结构光测量系统3DSS- STD- Ⅱ对标准下牙列模型从咬合面、右后侧牙列、前牙列区、左后侧牙列和正后方5个角度进行扫描，扫描后的结果经过数据合并、数据精简，利用反求软件Geomagic 6.0重建下颌牙列数字化模型。然后，用此软件自带测量工具测量切牙牙冠宽度、牙弓前段宽度、牙弓后段宽度、牙弓前段长度和牙弓后段长度相关指标，游标卡尺在石膏模型上测量各个相关指标，分析系统的可靠性、可重复性以及扫描精度。结果3DSS- STD- Ⅱ系统的可靠性与可重复性好，扫描精度结果显示与游标卡尺测量结果差异无统计学意义。结论新型结构光三维测量系统3DSS- STD- Ⅱ可靠性高、测量速度快，可以满足口腔模型三维数据快速采集和计算机辅助设计建模的需要。     

口内扫描数字化模型与硅橡胶制取石膏模型测量的对比研究

目的 研究应用口内扫描仪采集数字化牙颌模型与硅橡胶石膏模型测量之间的差异性.方法 选择口腔正畸科门诊初诊患者共30例,分别制取上下颌硅橡胶印模并灌制成超硬石膏模型;并用口内扫描仪（Trios,3Shape,丹麦）获取数字化模型并记录上下颌口内扫描时间.对口内数字化模型和石膏模型的牙齿宽度,牙弓长度、宽度,Spee＇s曲度进行测量,应用配对t检验分析各测量项目在两种模型测量的差异,独立样本t检验分析上下颌扫描时间、上下颌拥挤度的差异;重复测量计算组内相关系数（ICC）进行一致性检验.结果 两种模型上测量包含第一磨牙以前所有牙齿宽度,牙弓长度、宽度,Spee＇s曲度无统计学差异（P＞0.05）;所有重复测量ICC大于0.90.口内扫描时间上颌（411.9±162.2）s明显大于下颌（290.8±94.9）s,（P＜0.001）.结论 口内扫描获取的数字化模型与传统石膏模型测量之间无明显差异,有望在今后替代石膏模型.     

锥形束CT在三维数字化牙模建立中的初步应用

目的:研究应用锥形束CT(CBCT)采集数字化牙模的可靠性.方法:选择口腔正畸科门诊下颌前牙拥挤需要进行正畸治疗的成人患者共10例,常规取下颌印模并灌制成牙(牙合)模型.应用NewTom CBCT,选择6inch视野扫描石膏模型,重建三维数字牙模.由同一操作者间隔1周分别对石膏模型和数字模型的右下颌第一前磨牙宽度、牙弓宽度、牙弓长度和下前牙宽度等测量项目进行2次测量.应用配对t检验分析各测量项目在石膏模型和数字化模型测量间的差异,计算同一测量项目间隔1周并比较2种模型前后2次测量的绝对差别程度.采用SPSS13.0软件包对数据进行统计学处理.结果:2种模型上测量右下颌第一前磨牙宽度、牙弓宽度、牙弓长度、右下颌第一切牙宽度均无统计学差异.但在石膏模型上,测量所有下前牙宽度之和大于数字化模型上的测量值,有统计学差异(P<0.05).同一测量者在石膏模型上前后2次测量差值绝对值和数字化模型差值绝对值无显著差异(P>0.05).结论:CBCT生成的数字化牙(牙合)模型,与石膏模型线距测量结果的差别无显著性,应用CBCT重建的三维数字化牙(牙合)模型可作为研究模型来存储、测量.     

江苏地区正常的牙及牙弓测量研究

目的 测量125名江苏地区正常人群的模型,建立江苏地区正常牙及牙列指数的平均值。方法 选取正常模型125副(男61副,女64副),用电子游标卡尺测量牙冠宽度、牙弓宽度及长度、腭盖高度,对测量结果进行统计分析。结果 江苏地区正常人群的牙冠宽度、牙弓宽度及长度、腭盖高度均为男性大于女性,Bolton指数及Pont指数无性别差异。上下颌6个前牙牙冠宽度总和、全部牙冠宽度总和具有相关性,上颌中切牙与上颌前段牙弓宽度之间亦存在相关性,且建立了直线回归方程。结论 牙冠形态、牙列指数存在种族、地区和性别的差异,临床上应参照本民族、本地区的标准。     

Space conditions,palatal vault height,and tooth size in patients with and without palatally displaced canines: A prospective cohort study

Objectives:To assess palatal vault height, tooth size, and dental arch dimensions in patients with unilateral and bilateral palatally displaced canines compared with a control group.Materials and Methods:A sample of 66 patients (mean age: 11.5 ± 1.0 years) with 22 unilateral palatally displaced canines (UPDCs), 22 bilateral palatally displaced canines (BPDCs), and 22 controls (C) were consecutively recruited. All three groups had dental casts that were scanned digitally using the OrthoX three-dimensional model scanner. Tooth size, palatal vault height, dental arch width, dental arch depth, dental arch length, and dental arch space were measured by the same examiner using the GOM software. Remeasurements were made in 10 randomly identified patients.Results:The palatal vault height was significantly lower in the BPDC group compared with controls. A significantly smaller mesial-distal crown width and, in general, more spacing in the maxilla were found in the UPDC and BPDC groups. No differences in arch length or arch width at the molar region were seen between the groups, while the arch length at the canine region was smaller in the UPDC and BPDC groups. However, this was observed in BPDC patients with both deciduous canines present and in most UPDC patients where the deciduous canine was present, compared with the control group, who had more permanent canines present.Conclusions:Patients with PDC had greater reduction in tooth size compared with the control group. The arch length and arch width were similar in patients with and without PDC.     

Three-dimensional imaging of orthodontic models: a pilot study

Computer-based digital orthodontic models have been developed that have the potential to replace dental casts. The aim of this study was to examine the accuracy and reproducibility of measurements made on digital models. Ten sets of orthodontic study models were scanned using the Arius3D Foundation System and three-dimensional (3D) images were produced by computer software. Two examiners individually measured 11 parameters on the conventional casts and the digital models on two occasions. The parameters included mesio-distal crown diameter, intercanine and intermolar width, arch length, overjet, and incisor crown height. The measurement techniques were compared using paired t-tests, the coefficient of reliability, and by calculating mean values and the difference between methods. When comparing measurements made on digital models with those on dental casts, systematic errors were detected for five of the 11 parameters at the 10 per cent level. Random errors were a cause of concern for measurements of three parameters. The most accurate and reproducible measurements were lower intercanine width (mean difference between measurements 0.05 +/- 0.32 mm) and overjet (mean difference 0.07 +/- 0.33 mm). Most parameters on the digital models can be reliably measured, and digital models can potentially eliminate the requirement for the production and storage of dental casts, but this will depend on cost.     

重庆市正常(牙合)青少年牙颌模型测量研究

目的通过对92名重庆市正常（牙合）青少年的牙颌模型测量研究，建立重庆市正常（牙合）青少年的牙冠宽度和高度、牙弓宽度及长度、腭盖高度的均值及标准差，为正畸临床提供依据。方法，选取重庆市正常（牙合）青少年牙颌模型92付（男45付，女47付），用数显游标卡尺在模型上测量牙冠宽度、高度、牙弓宽度及长度、腭盖高度，对测量结果进行统计分析并与国内外的相关资料进行对比研究。结果重庆市正常（牙合）青少年的牙冠宽度、高度、牙弓宽度及长度、腭盖高度均为男性大于女性。各测量结果与国内外部分地区的报道有不同。结论人类的牙、牙弓存在种族、地区和性别差异，临床上应参照本地区的标准。     

Orthopedic outcomes of hybrid and conventional Hyrax expanders:: Secondary data analysis from a randomized clinical trial

ObjectivesTo compare the effects of a hybrid miniscrew-supported expander versus a conventional Hyrax (CH) expander in growing patients.Materials and MethodsForty patients were randomized into two groups: a hybrid Hyrax (HH) expander group using a Hyrax expander with two miniscrews and a CH expander group. The final sample had 18 subjects (8 female, 10 male; initial age of 10.8 years) in the HH group and 14 subjects (6 female, 8 male; initial age of 11.4 years) in the CH group. Cone-beam computed tomography examinations and digital dental models were obtained before expansion and 11 months postexpansion. The primary outcomes included the orthopedic transverse effects of expansion. Intergroup comparison was performed using analysis of covariance (P < .05).ResultsSignificantly greater increases in the nasal cavity width, maxillary width, and buccal alveolar crest width were found for the HH group. No intergroup differences were observed for dental arch width or shape changes.ConclusionsThe HH group showed greater increases in the nasal cavity width, maxillary width, and buccal alveolar crest width. No differences were observed for intermolar, interpremolar, or intercanine widths; arch length; or arch perimeter. Arch size and shape showed similar changes in both groups.     

A comparison of patient experience,chair-side time,accuracy of dental arch measurements and costs of acquisition of dental models

Objective:To compare patient experience, chairside time, dental arch distances, and costs of dental models derived from intraoral scans and alginate impressions in pre-orthodontic children and young adolescents.Materials and Methods:Fifty-nine children and young adolescents (9–15 years, mean: 12.70 years) had an intraoral scan and an alginate impression prior to orthodontic treatment. During the procedures, chairside time was registered in minutes and patient experience was assessed by a Visual Analogue Scale questionnaire. Four maxillary dental arch distances were measured on digital models, on plaster casts, and directly in the mouth (intraoral). The cost of each procedure was presented graphically. Differences between the two procedures were tested by paired t-test and general linear model.Results:Patient experience was statistically better during intraoral scan compared with alginate impression regarding comfort, gag reflex, breathing, smell/sound, taste/vibration, and all statements concerning anxiety (P < .05). No significant difference in chairside time between the two procedures was found. No statistically significant differences in dental arch distances between digital models and plaster casts were found, but dental arch distances measured intraorally differed significantly from both digital models and plaster casts (P < .05). Cost calculation showed that the digital procedure was 10.7 times more expensive than the conventional procedure initially and, that after 3.6 years, the two procedures were equal in cost.Conclusions:Children preferred intraoral scan rather than alginate impression. Chairside time was equal for the two procedures as were the measurements of maxillary dental arch distances. The two procedures were equal in cost at 3.6 years.     

替牙期62例上颌尖牙阻生儿童牙弓及腭部形态特征分析

目的:比较上颌尖牙阻生与无阻生儿童牙弓及腭部形态的差异,为上颌尖牙阻生早期识别和干预提供参考。方法:选择8~11岁[平均（9.82±1.04）岁]儿童62例,分为实验组（上颌尖牙阻生）和对照组（无上颌尖牙阻生）,每组31例。将2组患者石膏模型通过3D激光扫描后转化为数字模型,测量牙弓宽度、牙弓长度、基骨宽度、腭部宽度、腭部高度、腭部体积、表面积。采用 SPSS 24.0 软件包对实验数据进行配对t检验。结果:实验组儿童牙弓与腭部宽度相比对照组更窄（P<0.05）,但2组儿童在牙弓长度、基骨宽度、腭部高度方面无显著差异（P>0.05）。对照组儿童腭部体积、表面积显著大于实验组（P<0.05）。结论:替牙期上颌尖牙阻生儿童牙弓宽度、腭部宽度、腭部体积、表面积均小于对照组。早期诊断上颌尖牙阻生时,牙弓宽度、腭部宽度、体积、表面积均应纳入考虑。仅有上颌尖牙间牙弓宽度减小,不能作为上颌尖牙阻生的特异性判断指标。     

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??Abstract??Objective To obtain the data of dental measurements in healthy Bai teenagers. Methods Normal dentognathic models were obtained in 97 teenagers. The width of the tooth crown and the size of the dental arch were measured with a venier. The measurments were statistically analysed. Results The tooth crown in boys was wider than that in girls except first premolar and second premolar;the dental arch width and length in boys were wider than those in girls.There was no significant difference in Bolton index and Pont index between boys and girls. Conclusion The norms of teeth??denal arch and dentition index on normal occlusion in Bai teenagers have been established?? and they have a certain reference value to guide clinical orthodontics.