Medical rapid prototyping and 3D CT in the manufacture of custom made cranial titanium plates

This report describes a new method of custom making cranial titanium plates for the repair of skull defects. We have combined 3D CT imaging and surface modelling with rapid prototyping (RP) technology to produce physical models of our patients' skulls from which custom titanium plates were made. We have expanded the use of image processing tools applied to the CT image data to fabricate a representation of the skull defect. Medical RP models are relatively expensive and particular attention has been paid to developing image processing methods to reduce costs. Our technique used the patient as their own model and generated data from the contralateral side of the head where appropriate. We present the results of 10 patients who have had a custom made cranial titanium plate fitted and discuss the models for these cases. The benefits of our custom made titanium plates are reduced patient attendances to hospital and a more accurate titanium plate which has improved fitting and cosmesis.     

Design and fabrication of custom mandible titanium tray based on rapid prototyping

During the past few years, the combination of medical imaging and rapid manufacturing technique has proven to be a very important development. On the other hand, the conventional method has some drawbacks. For example, it takes longer time to complete an operation and it also presents some difficulty in matching the repaired contours. With advanced software and hardware, an image of an undamaged bone similar to that of the patient can be made from computerised tomography (CT); and a physical object constructed by the mirror-processed image data can be quickly fabricated with a high degree of fitting with the patient's bone. This paper presents a methodology for the design and fabrication of an individual titanium tray for the repair of mandible defects. Methods for the tray modeling using CAD system are presented: A 3D model of the bony defect is generated after the acquisition of helical CT data. An individual tray is designed using freeform surfaces geometries and fabricated by rapid prototyping (RP) technology. The results of tray filling with bone-grafting materials are then presented. Result: the tray is inserted into the patient mandible segment. The symmetry and reconstruction quality contour of the repaired mandible was satisfactory. Thus, the patient is able to eat normally. The bone-grafting material harvested from the anterior ilium was low. The clinical experience showed that rapid prototyping and reverse engineering software are effective methods of fabricating custom trays for mandibular reconstruction after bone loss due to a tumor.     

New layer-based imaging and rapid prototyping techniques for computer-aided design and manufacture of custom dental restoration

Fixed dental restoration by conventional methods greatly relies on the skill and experience of the dental technician. The quality and accuracy of the final product depends mostly on the technician's subjective judgment. In addition, the traditional manual operation involves many complex procedures, and is a time-consuming and labour-intensive job. Most importantly, no quantitative design and manufacturing information is preserved for future retrieval. In this paper, a new device for scanning the dental profile and reconstructing 3D digital information of a dental model based on a layer-based imaging technique, called abrasive computer tomography (ACT) was designed in-house and proposed for the design of custom dental restoration. The fixed partial dental restoration was then produced by rapid prototyping (RP) and computer numerical control (CNC) machining methods based on the ACT scanned digital information. A force feedback sculptor (FreeForm system, Sensible Technologies, Inc., Cambridge MA, USA), which comprises 3D Touch technology, was applied to modify the morphology and design of the fixed dental restoration. In addition, a comparison of conventional manual operation and digital manufacture using both RP and CNC machining technologies for fixed dental restoration production is presented. Finally, a digital custom fixed restoration manufacturing protocol integrating proposed layer-based dental profile scanning, computer-aided design, 3D force feedback feature modification and advanced fixed restoration manufacturing techniques is illustrated. The proposed method provides solid evidence that computer-aided design and manufacturing technologies may become a new avenue for custom-made fixed restoration design, analysis, and production in the 21st century.     

New layer-based imaging and rapid prototyping techniques for computer-aided design and manufacture of custom dental restoration

Fixed dental restoration by conventional methods greatly relies on the skill and experience of the dental technician. The quality and accuracy of the final product depends mostly on the technician's subjective judgment. In addition, the traditional manual operation involves many complex procedures, and is a time-consuming and labour-intensive job. Most importantly, no quantitative design and manufacturing information is preserved for future retrieval. In this paper, a new device for scanning the dental profile and reconstructing 3D digital information of a dental model based on a layer-based imaging technique, called abrasive computer tomography (ACT) was designed in-house and proposed for the design of custom dental restoration. The fixed partial dental restoration was then produced by rapid prototyping (RP) and computer numerical control (CNC) machining methods based on the ACT scanned digital information. A force feedback sculptor (FreeForm system, Sensible Technologies, Inc., Cambridge MA, USA), which comprises 3D Touch technology, was applied to modify the morphology and design of the fixed dental restoration. In addition, a comparison of conventional manual operation and digital manufacture using both RP and CNC machining technologies for fixed dental restoration production is presented. Finally, a digital custom fixed restoration manufacturing protocol integrating proposed layer-based dental profile scanning, computer-aided design, 3D force feedback feature modification and advanced fixed restoration manufacturing techniques is illustrated. The proposed method provides solid evidence that computer-aided design and manufacturing technologies may become a new avenue for custom-made fixed restoration design, analysis, and production in the 21st century.     

3D打印钛网在颅部骨缺损修复术中的应用

目的探讨3D打印钛网在颅部骨缺损修复术中的应用效果。方法回顾性分析我院88例行去骨瓣减压术的患者临床资料,按照手术方式分为观察组和对照组,对照组49例患者采用手工裁剪钛网行修补术,观察组39例患者采用3D打印钛网行修补术。比较2组患者手术修补时间、围术期并发症、钛钉固定数目和钛网厚度,随访5~17个月,比较2组患者随访期间并发症发生率。结果与对照组相比,观察组手术修补时间较短,围术期并发症发生率较低,钛钉固定数目较少,钛网厚度较小,差异均具有统计学意义(P<0.05)。随访期间,观察组并发症发生率低于对照组,差异具有统计学意义(P<0.05)。结论3D打印钛网在颅部骨缺损修复术中有较好的近期临床疗效,并发症较少,可精准、个体化地定制骨缺损修补材料。     

Porous titanium scaffolds fabricated using a rapid prototyping and powder metallurgy technique

One of the main issues in orthopaedic implant design is the fabrication of scaffolds that closely mimic the biomechanical properties of the surrounding bone. This research reports on a multi-stage rapid prototyping technique that was successfully developed to produce porous titanium scaffolds with fully interconnected pore networks and reproducible porosity and pore size. The scaffolds' porous characteristics were governed by a sacrificial wax template, fabricated using a commercial 3D-printer. Powder metallurgy processes were employed to generate the titanium scaffolds by filling around the wax template with titanium slurry. In the attempt to optimise the powder metallurgy technique, variations in slurry concentration, compaction pressure and sintering temperature were investigated. By altering the wax design template, pore sizes ranging from 200 to 400 microm were achieved. Scaffolds with porosities of 66.8 +/- 3.6% revealed compression strengths of 104.4+/-22.5 MPa in the axial direction and 23.5 +/- 9.6 MPa in the transverse direction demonstrating their anisotropic nature. Scaffold topography was characterised using scanning electron microscopy and microcomputed tomography. Three-dimensional reconstruction enabled the main architectural parameters such as pore size, interconnecting porosity, level of anisotropy and level of structural disorder to be determined. The titanium scaffolds were compared to their intended designs, as governed by their sacrificial wax templates. Although discrepancies in architectural parameters existed between the intended and the actual scaffolds, overall the results indicate that the porous titanium scaffolds have the properties to be potentially employed in orthopaedic applications.     

High-resolution 3D scaffold model for engineered tissue fabrication using a rapid prototyping technique

Rapid prototyping, automatic image processing (computer-aided design (CAD)) and computer-aided manufacturing techniques are opening new and interesting prospects for medical devices and tissue engineering, especially for hard tissues such as bone. The development of a bone high-resolution scaffold prototype using these techniques is described. The results testify to the fidelity existing between microtomographic reconstruction and CAD. Furthermore, stereolithographic manufacturing of this scaffold, which possesses a high degree of similarity to the starting model as monitored by morphological evaluations (mean diameter 569±147 μm), represents a promising result for regenerative medicine applications.     

Reverse engineering techniques applied to a human skull,for CAD 3D reconstruction and physical replication by rapid prototyping

The production of a copy of an existing object of complex shape is one of the typical applications of the integration between two modern computer-based technologies, reverse engineering (RE) and rapid prototyping (RP). The method is extremely versatile and can be used in various applicative domains (e.g. replacement of anatomical parts with artificial prostheses, replication of skeletal remains). Two different acquisition techniques of images of a skull, by laser and by CT scan, were compared to ascertain which enabled more accurate reproduction of the original specimen. The skull was chosen due to it being the body part most often used in medico-legal investigations (for personal identification, skull-photo superimposition techniques, forensic art, etc). Comparison between the copy and the original yielded satisfactory results for both techniques. However, CT scanning demonstrated some advantages over the laser technique, as it provided a cleaner point cloud, enabling shorter pre-reproduction processing times, as well as data on the internal parts, which resulted in the reproduction of a more faithful copy.     

Reverse engineering techniques applied to a human skull, for CAD 3D reconstruction and physical replication by rapid prototyping

The production of a copy of an existing object of complex shape is one of the typical applications of the integration between two modern computer-based technologies, reverse engineering (RE) and rapid prototyping (RP). The method is extremely versatile and can be used in various applicative domains (e.g. replacement of anatomical parts with artificial prostheses, replication of skeletal remains). Two different acquisition techniques of images of a skull, by laser and by CT scan, were compared to ascertain which enabled more accurate reproduction of the original specimen. The skull was chosen due to it being the body part most often used in medico-legal investigations (for personal identification, skull-photo superimposition techniques, forensic art, etc). Comparison between the copy and the original yielded satisfactory results for both techniques. However, CT scanning demonstrated some advantages over the laser technique, as it provided a cleaner point cloud, enabling shorter pre-reproduction processing times, as well as data on the internal parts, which resulted in the reproduction of a more faithful copy.     

髋关节置换手术定制型髓腔锉的设计与加工

目的 介绍定制型髓腔锉的设计与加工方法。方法 根据相应的定制型股骨柄假体的三维模型设计髓腔锉,在计算机辅助设计（CAD）软件中,通过截除、拉伸及偏移面等操作构建出髓腔锉三维模型。采用计算机辅助制造（CAM）技术加工出定制型髓腔锉。采用本研究的CAD及CAM方法,分别为实验及临床试用设计加工了定制型髓腔锉。结果 实验及临床试用的定制型髓腔锉被用于切削相应的尸体股骨腔及患者股骨腔,植入定制型假体以后,通过分析发现假体与股骨腔匹配较好。结论 采用该研究方法设计加工定制型髓腔锉,将能够提高植入定制型股骨柄假体的成功率,将减少定制型股骨柄假体在患者股骨腔中松动的风险,能够促进股骨松质骨长入假体表面来固定假体。     

快速原型技术在颅颌面整复中的应用

快速原型(rapidprototyping,RP)技术作为一种全新的成形制造技术,具有多方面的优越性和适用性,已深入到医学领域的诸多学科,其中颅颌面整复方面的研究更显活跃。概括介绍快速原型技术及其在颅颌面整复方面的研究近况并展望其应用前景。     

快速成型技术原理及其医学应用

随着社会需要和科学技术的发展,产品更新的周期越来越短,因而要求设计者不但能根据市场的要求很快地设计新产品,而且能在尽可能短的时间内制造出产品,进行必要的性能测试,征求用户的意见,并进行修改,最后形成能投放市场的定型产品.     

快速成型技术在骨科的应用研究进展

快速成型技术是20世纪80年代中期发展起来的,它是在计算机控制下,根据物体的CAD模型或CT等数据,不借助其他设备,通过材料的精确堆积,制造原型的一种基于离散、堆积成型原理的新的数字化成型技术;近年来通过与螺旋CT或核磁共振等检测手段的三维图像重建功能相结合,在骨科领域显示出良好的应用前景。综述了该技术在骨科领域内的器官模型制备和手术策划、个体化假体制备、骨组织工程多孔支架制备等主要应用方向的研究进展。     

口腔内扫描和三维打印在可摘局部义齿制造中的应用

文题释义： 可摘局部义齿：是一种患者可以自行摘戴的用于部分牙缺失或缺损的修复体。义齿主要通过固定在余留天然牙上的卡环等固位装置和基托保持义齿在牙列中的位置,利用天然牙和缺牙区剩余牙槽嵴做支持,恢复缺失牙及其周围缺损组织的解剖形态和生理功能。 三维打印：即快速成形技术的一种,它是一种以数字模型文件为基础,运用粉末状金属或塑料等可黏合材料,通过逐层打印的方式来构造物体的技术,过去其常在模具制造、工业设计等领域被用于制造模型,现正逐渐用于一些产品的直接制造,目前在医疗领域,关节、骨与牙齿已经有使用这种技术打印而成的零部件。 背景：在国内可摘局部义齿制备中尚无成熟的计算机辅助设计与制造系统,也无大样本的病例应用报道,现有研究多数只观察了少数病例的试戴效果,临床数据尚需积累和丰实。 目的：探讨口腔内扫描和三维打印在可摘局部义齿制造中的应用价值。 方法：选择上海交通大学医学院附属第九人民医院2014年6至12月收治的63例KennedyⅠ类牙列缺损患者,其中男29例,女34例,年龄44-63岁,研究组23例采用口腔内扫描和三维打印方式制备义齿支架,对照组40例采用传统印模方式制备义齿支架。对比两组试戴效果;修复前及修复后6,12,24个月,对比两组咀嚼效率;末次随访时,对比两组患者满意度及并发症发生情况。试验获得上海交通大学医学院附属第九人民医院委员会批准(批准号：TJBDYY-2014-13-R1,批准时间：2014年3月)。 结果与结论：①试戴后,研究组适合性、固位性和稳定性均高于对照组(适合性：96%,70%;固位性：83%,58%;稳定性：83%,53%,P均< 0.05);②修复前与修复后6个月,两组间咀嚼效率比较差异无显著性意义(P > 0.05);修复后12,24个月,研究组咀嚼效率高于对照组(P < 0.05);③研究组患者舒适满意度高于对照组(82%,50%,P < 0.05),美观和发音功能满意度与对照组比较差异无显著性意义(美观满意度：70%,53%;发音功能满意度：65%,40%,P > 0.05);④研究组基牙牙周病发生率、义齿性口腔炎发生率及继发性龋病发生率与对照组比较差异均无显著性意义(基牙牙周病发生率：0,5%;义齿性口腔炎发生率：4%,5%;继发性龋病发生率：9%,18%,P > 0.05);⑤结果表明,口腔内扫描和三维打印可获得较传统印模方式更加准确、稳定的支架模型,具有较高的临床应用价值。ORCID: 0000-0001-9360-4126(苏庭舒) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

高精度快速成型模型的制作精度及其体外细胞毒性

背景：快速成型技术在手术模拟与组织工程研究的应用日益广泛,而现场手术模拟和术前指导对模型的精度要求非常高,且在术中使用模型应要求其对人体无毒性。 目的：评估不同后处理方法快速成型模型的成型精度及其细胞毒性。 方法：采用选择性激光烧结技术制作标准圆柱体样品模型,并经浸蜡或树脂处理后,测量模型的高度和底面直径,评估其成型精度。然后采用噻唑蓝法研究不同后处理的模型件对小鼠成纤维细胞L929和小鼠前成骨细胞MC3T3-E1的毒性作用。实验分为石蜡处理组、树脂处理组、阴性对照组(未处理模型)、空白对照组(新鲜培养基)及阳性对照组(体积分数5%的DMSO),培养2 d后,490 nm处测量吸光度,并计算其相对增殖率和评价细胞毒性等级。 结果与结论：浸蜡、树脂处理后的模型以及模型原件的精度为95%~97%,误差为0.5~1 mm。模型浸提液培养L929和MC3T3-E1细胞2 d后,各实验组的细胞相对增殖率均大于80%,石蜡处理后的快速成型模型对L929和MC3T3-E1有较低的毒性作用,而树脂处理和未处理的模型对这两种细胞均无毒性作用,细胞毒性均为0~1级。     

钛板在胸骨肿瘤胸骨切除治疗中的运用

背景：胸骨肿瘤一旦扩大切除,会导致巨大胸骨壁缺损,若不进行修复,正常胸廓的稳定性和胸腔的密闭性不能保持,常会引起严重的反常呼吸运动。组织工程材料在胸骨肿瘤中的应用是现在的研究热点。 目的：探讨探讨组织工程学用于胸骨切除后胸廓重建的方法和临床效果,综述其修复过程中组织工程化材料的研究成果。 方法：应用计算机检索1990-01/2011-02 PubMed数据库及维普数据库有关组织工程学在胸骨切除术后胸廓重建中的应用的生物力学分析、组织工程材料在胸骨重建中应用及胸骨肿瘤扩大切除术后组织材料在其中的应用的相关文献,英文检索词“stemal tumors,reconstruction”,中文检索为“胸骨肿瘤,胸廓重建,钛板”,检索文献量总计100篇。 结果与结论：目前胸廓重建材料分为生物材料和人工材料两大类,包括自体移植的骨、心包、筋膜和异体的牛筋膜、心包等。钛板能够保证有效手术后胸廓的稳定性,并且钛板具有不易发生排异反应,可在体内长期存留,便于消毒灭菌,不影响CT检查,便于塑型及固定,方便、安全性高,而且修复、整形的效果好,但长期疗效仍有待进一步观察。     

序列二维医学图像的三维显示法

详细综述了对序列二维医学图像进行三维显示的各种方法，进一步展示了该领域的最新发展方向。在比较各种显示技术的基础上，针对不同应用场合：计算机辅助手术实时导航系统和术前高精度诊疗系统，提出了不同的三维显示法。     

精确锥形束CT和扇形束CT三维变形配准

自适应放疗可根据患者解剖和/或生理的变化对放疗计划进行修正。与加速器集成的锥形束CT成像装置是最普遍的在线影像获取设备。但是,由于锥形束CT固有的电子散射,重建影像的电子密度不准确,使得通常采用的基于密度的配准算法配准计划扇形束CT和在线获取的锥形束CT影像时,会产生较大的配准误差。我们通过建模图像变形配准问题为一个求解梯度距离能量泛函的极值问题,然后通过变分法和Gauss-Seidel方法获得一种新型的基于梯度信息的变形配准算法的迭代公式。该方法在迭代过程中同时考虑梯度信息的吻合和变形场的连续性,产生准确光滑的变形场。此算法迭代公式的局部特性,使其便于并行实施。通过OpenCL编程将此算法在图形处理器(GPU)上并行实施,大大缩短了配准时间。利用配准结果结合flood filling和cubic matching算法,可以快速地完成在线器官映射。算法临床数据配准结果表明,本文提出的基于梯度场的配准算法与基于密度的算法相比可以更准确地配准临床锥形束CT和扇形束CT影像。由于配准可以在很短的时间内完成,配准结果可用于在线器官映射和在线重新计划优化。     

A review of rapid prototyping (RP) techniques in the medical and biomedical sector

The evolution of rapid prototyping (RP) technology is briefly discussed, and the application of RP technologies to the medical sector is reviewed. Although the use of RP technology has been slow arriving in the medical arena, the potential of the technique is seen to be widespread. Various uses of the technology within surgical planning, prosthesis development and bioengineering are discussed. Some possible drawbacks are noted in some applications, owing to the poor resolution of CT slice data in comparison with that available on RP machines, but overall, the methods are seen to be beneficial in all areas, with one early report suggesting large improvements in measurement and diagnostic accuracy as a result of using RP models.