3shape Trios 3口内扫描和传统硅橡胶在牙体缺损修复中的失败原因分析

目的分析并比较3shape Trios 3口内扫描和传统硅橡胶在牙体缺损修复中的失败原因,为临床取模以及口内扫描仪性能改善提供参考依据。方法回顾性分析2021年1月至2023年10月实施口腔固定修复治疗并返工的200例患者为研究对象,以取模方式将其分为口扫组(n=97)和硅橡胶组(n=103)。口扫组给予3shape Trios 3口内扫描,硅橡胶组给予传统硅橡胶。比较两组在牙体缺损修复中的失败原因。结果两组的牙体缺损修复失败分布情况比较,差异具有统计学意义(P<0.05);口扫组中,龈下缺损修复失败占比高于龈上(P<0.05)。两组的龈下缺损修复失败原因比较,差异具有统计学意义(P<0.05)。结论相较于传统硅橡胶,3shape Trios 3口内扫描在龈上缺损修复中更有优势,但在龈下缺损修复中,硅橡胶应用效果更佳。

3D Ice Shape Description Method Based on BLSOM Neural Network

When checking the ice shape calculation software,its accuracy is judged based on the proximity between the calculated ice shape and the typical test ice shape.Therefore,determining the typical test ice shape becomes the key task of the icing wind tunnel tests.In the icing wind tunnel test of the tail wing model of a large amphibious aircraft,in order to obtain accurate typical test ice shape,the Romer Absolute Scanner is used to obtain the 3D point cloud data of the ice shape on the tail wing model.Then,the batch-learning self-organizing map(BLSOM)neural network is used to obtain the 2D average ice shape along the model direction based on the 3D point cloud data of the ice shape,while its tolerance band is calculated using the probabilistic statistical method.The results show that the combination of 2D average ice shape and its tolerance band can represent the 3D characteristics of the test ice shape effectively,which can be used as the typical test ice shape for comparative analysis with the calculated ice shape.

3shape扫描石膏模型联合3D打印制作可摘局部义齿支架的临床疗效

目的探讨3shape扫描石膏模型联合3D打印制作可摘局部义齿支架与失蜡铸造法加工局部义齿支架的临床效果和差异。方法采用回顾性研究方法,筛选采用两种技术修复多颗前磨牙及磨牙缺失的患者进行研究。A组患者为采用3shape扫描联合3D打印制作可摘局部义齿支架的患者60例,B组患者为采用失蜡铸造法制作可摘局部义齿支架的患者60例。分析2组患者最终可摘局部义齿的初戴时间,修复体模型在前磨牙、磨牙区、义齿后缘处位点的偏差值,患者的满意度,以及最终修复体外形和边缘适合性的差异。结果2组患者的可摘局部义齿的初戴时间,修复体模型在前磨牙、磨牙区、义齿后缘处位点的偏差值比较差异有统计学意义(P<0.05);最终修复体外形及边缘适合性比较差异无统计学意义(P>0.05)。结论3shape扫描石膏模型联合3D打印制作可摘局部义齿支架比失蜡铸造法制作支架能够缩短患者修复体初戴时间,提高患者的满意度。

基于3shape数字化扫描制作的临时和长期修复体在拔牙后即刻种植中的应用

目的:探讨基于3shape数字化扫描制作的临时和长期修复体在拔牙后即刻种植中的临床应用效果。方法:采用前瞻性自身对照实验设计,选取我院口腔科2020年6月—2021年3月期间参与即刻种植的60例患者作为研究对象,并分为对照组和试验组,每组各30例,对照组采用传统加工方法制作螺丝固位树脂临时修复体,试验组采用3shape Trios系统辅助制作系统加工制作螺丝固位二硅酸锂修复体,对比两组患者的短期疗效、满意度情况和远期效果。结果:试验组的修复体精准度高于对照组,且WES评分低于对照组(P<0.05);试验组的临床修复时间低于对照组,且平均VAS满意度评分高于对照组(P<0.05);试验组在边缘适应性、解剖外形方面达到优秀的例数均多于对照组(P<0.05)。结论:基于3shape数字化扫描的二硅酸锂修复体在即刻种植中表现优越,具有高修复精准度、短修复时间及高患者满意度。

传统和3shape Trios口内印模技术制作全瓷高嵌体的临床效果比较

目的:评价并比较3shape Trios口内印模技术与传统硅橡胶印模技术在全瓷高嵌体修复中的临床效果。方法:将需行全瓷高嵌体修复的80颗患牙随机分为直接组和间接组(40颗/组)。直接组采用3shape Trios口内扫描仪采集数字化模型,间接组采用硅橡胶印模翻制石膏模型后,再从石膏模型上制取光学模型,分别记录取模时间、患者舒适度。修复体试戴时记录修复体调改时间,修复完成后2个月采用改良的美国公共卫生署(USPH S)标准对修复体进行评价。结果:直接组取模时间和修复体调改时间显著短于间接组(P<0.05);取模时患者舒适度显著优于间接组(P<0.05);制作的修复体边缘适合性及颜色显著优于间接组(P<0.05);两组间修复体外形和质地差异无统计学意义(P>0.05)。结论:与传统硅橡胶印模相比较,3shape Trios口内印模技术在全瓷高嵌体临床应用中效果更佳,值得临床推广。

3Shape Trios口内扫描与精细硅橡胶印模技术在临床瓷贴面修复中的应用比较

目的比较数字化口内扫描技术与传统硅橡胶精细印模技术在临床前牙瓷贴面修复中的差异。方法本研究选择西安交通大学口腔医院综合科进行前牙瓷贴面修复的患者共64例,其中试验组30例采用3shape trios口内扫描仪取数字化印模,对照组34例采用传统硅橡胶印模技术制取印模。修复体完成2周后对两组患者进行修复整体满意度调查,并在修复体完成后2月,按改良美国公共卫生署(USPHS)标准对两组修复体进行检查,对修复体固位、边缘密合度、颜色形态等进行评价。结果本试验中瓷贴面修复体共计152颗,其中72颗采用数字化扫描完成修复。经调查试验组患者满意度为94.4%,对照组患者满意度为88.7%。医生客观检查(USPHS)统计结果显示,试验组在边缘适合性、边缘染色、修复体外形及牙龈健康方面优于对照组,且差异具有统计学意义(P<0.05)。结论 3Shape Trios直接口内数字化印模技术在前牙瓷贴面修复的临床应用中能够明显增加修复体边缘密合度,有利于牙周健康,并且该方法舒适度高更易被患者接受。

3 Shape Trios口内扫描仪制作全瓷冠桥修复体的临床效果

目的 观察3 Shape Trios口内扫描仪制作全瓷冠桥修复体的临床效果。方法 选择2014年9月-2015年12月在我科就诊的患者52例,用3 Shape Trios口内扫描仪采集数字化模型并按照标准程序共CAD/CAM制作二氧化锆全瓷冠桥187个单位修复体,修复完成后患者填写满意度调查表。修复完成2个月时根据改良的USPHS标准对修复体进行评价。结果 共制作二氧化锆全瓷冠桥187个单位修复体,患者总体满意度为98%。结论 3 Shape Trios口内扫描仪CAD/CAM制作全瓷冠桥具有显著的临床效果，

3 Shape Trios口内扫描仪制作全瓷贴面的临床效果

目的观察3 shape Trios口内扫描仪CAD/CAM制作前牙全瓷贴面进行修复的临床效果。方法选择42例患者使用3 shape Trios共修复前牙全瓷贴面176例。2个月后按照改良美国公共健康协会(USPHS)标准对修复体进行评价。结果 42例患者使用3 shape Trios共修复176颗前牙修复体,患者满意度为100%。结论 3 shape Trios口内扫描仪CAD/CAM制作的全瓷贴面能够满足临床上前牙美观修复和功能恢复。

Modeling of Ni_4Ti_3 precipitation during stress-free and stress-assisted aging of bi-crystalline NiTi shape memory alloys

The phase field method was applied to study the microstructure evolution of Ni4Ti3 precipitates during stress-free and stress-assisted aging of bi-crystalline NiTi shape memory alloys （SAMs） with two different initial Ni-contents of 51.5% and 52.5% （mole fraction）, respectively. The simulation results show that, during stress-free aging of the NiTi alloy with a low supersaturation of Ni （i.e., Ti-51.5%Ni）, the Ni4Ti3 precipitates exhibit a heterogeneous distribution with a high number density of particles at the grain boundary, leaving most of the grain interiors free of precipitates; while for the NiTi alloy with a high supersaturation of Ni （i.e., Ti-52.5%Ni）, the Ni4Ti3 precipitates show a homogeneous distribution across the entire simulation system. The stress-assisted aging can give rise to homogeneous distribution of the precipitates, regardless of the initial Ni-content; however, the distribution of variant type within the two grains is heterogeneous.

棒状结构NaGdF_(4):Yb^(3+),Er^(3+)上转换发光性能的研究

以乙二胺四乙酸二钠(EDTD-2Na)为螯合剂,采用水热法合成了棒状结构的NaGdF_(4):Yb^(3+),Er^(3+)纳米粉末。分别借助X射线衍射(XRD)、荧光光谱仪(PL)和扫描显微镜(SEM)对其晶体结构、发光强度和表面形貌进行分析和表征。探究了稀土前驱体、水热温度和水热时间的实验条件对NaGdF_(4):Yb^(3+),Er^(3+)纳米粉末上转换发光强度的影响;研究了氟源和钠源对NaGdF_(4):Yb^(3+),Er^(3+)晶体形貌和上转换发光强度的改善;同时,采用煅烧处理的方法,进一步探究样品的形貌和发光强度收到的影响。实验结果表明NH4F与NaOH作为氟源和钠源及200℃煅烧1 h得到的棒状结构NaGdF_(4):Yb^(3+),Er^(3+)的发光强度最好,色坐标(CIE)绿色发光强度从84%提升到94.88%。

Vision Based Hand Gesture Recognition Using 3D Shape Context

Hand gesture recognition is a popular topic in computer vision and makes human-computer interaction more flexible and convenient.The representation of hand gestures is critical for recognition.In this paper,we propose a new method to measure the similarity between hand gestures and exploit it for hand gesture recognition.The depth maps of hand gestures captured via the Kinect sensors are used in our method,where the 3D hand shapes can be segmented from the cluttered backgrounds.To extract the pattern of salient 3D shape features,we propose a new descriptor-3D Shape Context,for 3D hand gesture representation.The 3D Shape Context information of each 3D point is obtained in multiple scales because both local shape context and global shape distribution are necessary for recognition.The description of all the 3D points constructs the hand gesture representation,and hand gesture recognition is explored via dynamic time warping algorithm.Extensive experiments are conducted on multiple benchmark datasets.The experimental results verify that the proposed method is robust to noise,articulated variations,and rigid transformations.Our method outperforms state-of-the-art methods in the comparisons of accuracy and efficiency.

西安地区3~6岁儿童脚型分类及特征规律分析

针对当前市场童鞋设计不合理和缺乏儿童脚型理论研究参考问题,本研究首先使用三维足部扫描仪获取到3~6岁的52名男童和71名女童三维脚型数据,进行儿童脚型特点和差异的对比分析;其次,采用相关性分析和主成分分析将26组多维指标降维处理至3个主成分:脚长因子、宽围因子和高度因子;然后,以提取的3个主成分作为分类标准进行H-K聚类分析,将儿童脚型分为3类:细瘦足、适中足、肥壮足,其中左脚细瘦足占比最多,右脚适中足占比最多;最后,将脚长尺寸标准化,发现儿童脚型存在显著的性别及左右脚差异.该研究结论可为童鞋设计和鞋楦三维数字化构建提供理论参考.

3D printed ultra-fast photothermal responsive shape memory hydrogel for microrobots

Hydrogels with stimuli-responsive capabilities are gaining more and more attention nowadays with prospective applications in biomedical engineering,bioelectronics,microrobot,etc.We develop a photothermal responsive hydrogel based on N-isopropylacrylamide that achieved a fast and reversible deformation manipulated only by near-infrared(NIR)light.The hydrogel was fabricated by the projection micro stereolithography based 3D printing technique,which can rapidly prototype complex 3D structures.Furthermore,with the variation of the grayscale while manufacturing the hydrogel,the deformation of the hydrogel structure can be freely tuned within a few seconds by losing and absorbing water through adjusting the intensity and the irradiation direction of the NIR light,showing a potential application in ultra-fast object grabbing and transportation.The present study provides a new method for designing ultrafast photothermal responsive hydrogel based microrobot working in water.

PCA-based 3D Shape Reconstruction of Human Foot Using Multiple Viewpoint Cameras

This paper describes a multiple camera-based method to reconstruct the 3D shape of a human foot. From a foot database, an initial 3D model of the foot represented by a cloud of points is built. The shape parameters, which can characterize more than 92% of a foot, are defined by using the principal component analysis method. Then, using ＂active shape models＂, the initial 3D model is adapted to the real foot captured in multiple images by applying some constraints （edge points＇ distance and color variance）. We insist here on the experiment part where we demonstrate the efficiency of the proposed method on a plastic foot model, and also on real human feet with various shapes. We propose and compare different ways of texturing the foot which is needed for reconstruction. We present an experiment performed on the plastic foot model and on human feet and propose two different ways to improve the final 3D shapers accuracy according to the previous experiments＇ results. The first improvement proposed is the densification of the cloud of points used to represent the initial model and the foot database. The second improvement concerns the projected patterns used to texture the foot. We conclude by showing the obtained results for a human foot with the average computed shape error being only 1.06 mm.

Panicle-3D: A low-cost 3D-modeling method for rice panicles based on deep learning, shape from silhouette, and supervoxel clustering

Self-occlusions are common in rice canopy images and strongly influence the calculation accuracies of panicle traits. Such interference can be largely eliminated if panicles are phenotyped at the 3 D level.Research on 3 D panicle phenotyping has been limited. Given that existing 3 D modeling techniques do not focus on specified parts of a target object, an efficient method for panicle modeling of large numbers of rice plants is lacking. This paper presents an automatic and nondestructive method for 3 D panicle modeling. The proposed method integrates shoot rice reconstruction with shape from silhouette, 2 D panicle segmentation with a deep convolutional neural network, and 3 D panicle segmentation with ray tracing and supervoxel clustering. A multiview imaging system was built to acquire image sequences of rice canopies with an efficiency of approximately 4 min per rice plant. The execution time of panicle modeling per rice plant using 90 images was approximately 26 min. The outputs of the algorithm for a single rice plant are a shoot rice model, surface shoot rice model, panicle model, and surface panicle model, all represented by a list of spatial coordinates. The efficiency and performance were evaluated and compared with the classical structure-from-motion algorithm. The results demonstrated that the proposed method is well qualified to recover the 3 D shapes of rice panicles from multiview images and is readily adaptable to rice plants of diverse accessions and growth stages. The proposed algorithm is superior to the structure-from-motion method in terms of texture preservation and computational efficiency. The sample images and implementation of the algorithm are available online. This automatic, cost-efficient, and nondestructive method of 3 D panicle modeling may be applied to high-throughput 3 D phenotyping of large rice populations.

3D Engineering Model Retrieval Based on Enhanced Shape Distributions

To reuse and share the valuable knowledge embedded in repositories of engineering models for accelerating the design process, improving product quality, and reducing costs, it is crucial to devise search engines capable of matching 3D models efficiently and effectively. In this paper, an enhanced shape distributions-based technique of using geometrical and topological information to search 3D engineering models represented by polygonal meshes was presented. A simplification method of polygonal meshes was used to simplify engineering model as the pretreatment for generation of sample points. The method of sampling points was improved and a pair of functions that was more sensitive to shape was employed to construct a 2D shape distribution. Experiments were conducted to evaluate the proposed algorithm utilizing the Engineering Shape Benchmark (ESB) database. The experiential results suggest that the search effectiveness is significantly improved by enforcing the simplification and enhanced shape distributions to engineering model retrieval.

Influence of Nozzle Orifice Shape on the Atomization Process of Si3N4 in a Dry Granulation Process

In order to reveal the intrinsic fluid-dynamic mechanisms of a pressure-swirl nozzle used for Si3N4 dry granulation,and effectively predict its external spray characteristics,the dynamics of air-atomized liquid two-phase flow is analyzed using a VOF(Volume of Fraction)method together with the modified realizable k-εturbulence model.The influence of nozzle orifice shape on velocity distribution,pressure distribution is studied.The results show that the pressure difference in a convergent conical nozzle is the largest with a hollow air core being formed in the nozzle.The corresponding velocity of atomized liquid at nozzle orifice is the largest.Using a self-designed atomization experiment platform,the velocity and pressure of atomized liquid and the spray cone angle are measured for three nozzles with different orifice shapes.The micro-morphology of Si3N4 particles is also determined.These data confirm the correctness of numerical simulation.Considering atomization performance of the nozzle,the contraction conical nozzle is more suitable for the atomization of Si3N4 in practical production based on the dry granulation approach.

3shape Trios口内扫描在种植修复中的护理应用及效果评价

目的探讨3shape Trios口内扫描在种植修复中的护理应用及效果评价。方法简单随机选取2018年10月—2019年10月在该院进行治疗的种植修复患者100例,随机分为两组,对照组应用传统的硅橡胶印模,研究组应用3shape Trios扫描仪数字化印模,并配合相应的护理措施。并对两组患者舒适度、满意度及印模优势进行比较。结果研究组满意评分(80.33±4.23)分、舒适度评分(81.67±4.23)分高于对照组(76.23±2.31)分、(69.31±3.33)分,重复印模(1.25±0.49)次少于对照组(4.23±0.31)次,差异有统计学意义(t=6.015、16.235、36.341,P<0.001)。结论数字化印模相对传统印模它提高了患者的舒适度减少了重复印模的次数和就诊时间,无需印模材料和运输,减少了材料的成本和模型在途中丢失及损坏的风险。数字化印模有着方便、快捷、精准的优势,在种植修复中,将会逐步替代传统印模技术,成为广泛应用的口内数据采集基本手段。

Real-Time Characterization of Crystal Shape and Size Distribution Based on Moving Window and 3D Imaging in a Stirred Tank

Crystal shape distribution, i.e. the multidimensional size distribution of crystals, is of great importance to their down-stream processing such as in filtration as well as to the end-use properties including the dissolution rate and bioavailability for crystalline pharmaceuticals. Engineering crystal shape and shape distribution requires knowledge about the growth behavior of different crystal facets under varied operational conditions e.g. supersaturations. Measurement of the facet growth rates and growth kinetics of static crystals in a crystallizer without stirring has been reported previously. Here attention is given to study on real-time characterization of the 3D facet growth behavior of crystals in a stirred tank where crystals are constantly moving and rotating. The measurement technique is stereo imaging and the crystal shape reconstruction is based on a stereo imaging camera model. By reference to a case study on potash alum crystallization, it is demonstrated that the crystal size and shape distributions (CSSD) of moving and rotating potash alum crystals in the solution can be reconstructed. The moving window approach was used to correlate 3D face growth kinetics with supersaturation (in the range 0.04 - 0.12) given by an ATR FTIR probe. It revealed that {100} is the fastest growing face, leading to a rapid reduction of its area, while the {111} face has the slowest growth rate, reflected in its area continuously getting larger.

Prediction of Weld Joint Shape and Dimensions in Laser Welding Using a 3D Modeling and Experimental Validation

This paper presents an experimentally validated weld joint shape and dimensions predictive 3D modeling for low carbon galvanized steel in butt-joint configurations. The proposed modelling approach is based on metallurgical transformations using temperature dependent material properties and the enthalpy method. Conduction and keyhole modes welding are investigated using surface and volumetric heat sources, respectively. Transition between the heat sources is carried out according to the power density and interaction time. Simulations are carried out using 3D finite element model on commercial software. The simulation results of the weld shape and dimensions are validated using a structured experimental investigation based on Taguchi method. Experimental validation conducted on a 3 kW Nd: YAG laser source reveals that the modelling approach can provide not only a consistent and accurate prediction of the weld characteristics under variable welding parameters and conditions but also a comprehensive and quantitative analysis of process parameters effects. The results show great concordance between predicted and measured values for the weld joint shape and dimensions.