立体摄影颌面部软组织三维重建与测量的研究进展

颌面部软组织三维重建及其在此基础上的测量，在口腔颌面外科学、口腔正畸学、整形外科学、法医学、人类学及美学等领域有着很重要的意义。在面部软组织重建与测量方面，出现了激光扫描、立体摄影、莫尔云纹、结构光技术、CT、MRI等方法，但各有利弊。面部软组织三维立体摄影测量（stereopho-togrammetry）在20世纪90年代初即开始出现。     

面部软组织的三维测量系统的开发和应用

目的 开发一套面部软组织三维测量系统,以融合测量与图像技术作为一种客观的手段,协助医生为患者提供更好的服务。方法 利用2个CCD摄像头、识别标志点的实时硬件以及测量软件,集成一套三维测量系统。结果 该系统能对面部软组织进行高效、简便的三维测量,而且对受检者无损伤。结论 本系统是获取面部三维信息的一种有效手段,对传统测量方法是个很好的补充。     

Orthognathic patient perception of 3D facial soft tissue prediction planning

The primary aim of this study was to explore patients’ perceptions regarding the impact of 3D prediction planning (3D PP) of facial soft tissue changes following orthognathic surgery.The study was carried out on 30 patients who were shown photorealistic 3D soft tissue prediction planning before undergoing orthognathic surgery to demonstrate the expected facial changes. Distraction osteogenesis and cleft deformities were excluded from the study before consenting to surgery. Following surgery, the included patients were asked to complete a standard questionnaire to explore their perceptions regarding the impact, accuracy, and value of 3D prediction planning.The majority of the 30 participants perceived 3D PP to be beneficial in reducing their presurgical anxiety, increasing their motivation to undergo surgery, improving the accuracy of their surgical expectations, and enhancing doctor–patient communication. Most of the patients perceived their surgical soft tissue changes to be better than the predictions. Significant positive correlations were detected between satisfaction with the delivered service and the facility of seeing 3D PP (r_s = 0.4; p = 0.034). Similarly, 3D PP improved patients’ confidence in the surgical decision (r_s = 0.4; p = 0.031), as well as increasing their motivation to undergo surgery (r_s = 0.5; p = 0.010).3D PP was found to be effective in improving the quality of orthognathic surgical care.     

Soft tissue response to mandibular advancement using 3D CBCT scanning

This prospective longitudinal study assessed the 3D soft tissue changes following mandibular advancement surgery. Cranial base registration was performed for superimposition of virtual models built from cone beam computed tomography (CBCT) volumes. Displacements at the soft and hard tissue chin (n = 20), lower incisors and lower lip (n = 21) were computed for presurgery to splint removal (4-6-week surgical outcome), presurgery to 1 year postsurgery (1-year surgical outcome), and splint removal to 1 year postsurgery (postsurgical adaptation). Qualitative evaluations of color maps illustrated the surgical changes and postsurgical adaptations, but only the lower lip showed statistically significant postsurgical adaptations. Soft and hard tissue chin changes were significantly correlated for each of the intervals evaluated: presurgery to splint removal (r = 0.92), presurgery to 1 year postsurgery (r = 0.86), and splint removal to 1 year postsurgery (r = 0.77). A statistically significant correlation between lower incisor and lower lip was found only between presurgery and 1 year postsurgery (r = 0.55). At 1 year after surgery, 31% of the lower lip changes were explained by changes in the lower incisor position while 73% of the soft tissue chin changes were explained by the hard chin. This study suggests that 3D soft tissue response to mandibular advancement surgery is markedly variable.     

Three-Dimensional Soft Tissue Prediction Using Finite Elements

Abstract Background and Aim: The prediction of soft tissue esthetics is important for achieving an optimal esthetic outcome in orthodontic treatment planning. Applicable procedures have so far been restricted to two-dimensional profile predictions that have not proven to be very reliable. The goal of this investigation was therefore to develop a novel finite element-based procedure that allows a three-dimensional, easily visualized, quantitative analysis and prediction of soft tissue behavior for the clinician. The procedure to be developed should be easy to handle and not entail any additional radiation exposure for the patient. Material and Methods: Using a three-dimensional scanner, the facial surfaces of 20 probands were digitalized and individual FEM models were generated. Results: After reduction of data redundancy via several conversion steps, a patient-specific simulation model was prepared consisting of 20,000 to 40,000 individual elements to which specific physical properties could be assigned. The average time required for generating a virtual model was 50 minutes. Problems occurring during model generation were rare (mainly shadowing phenomena and movement artifacts). Conclusion: The procedure outlined herein makes the reliable generation of patient-specific simulation models possible for facial soft tissue prediction in orthodontics.     

Changes in Soft Tissue Profile After Orthodontic Treatment With and Without Extraction: A Systematic Review and Meta-analysis

Objective

The objective of this systematic review and meta-analysis was to evaluate the soft tissue changes in adult orthodontic patients who received extraction treatment in comparison to their counterparts who received nonextraction orthodontic treatment.

Precision and accuracy assessment of single and multicamera three-dimensional photogrammetry compared with direct anthropometry

ObjectivesTo assess the precision and accuracy of single-camera photogrammetry (SCP) and multicamera photogrammetry (MCP) compared with direct anthropometry (DA).Materials and MethodsA total of 30 participants were recruited, and 17 soft tissue landmarks were identified and used to complete a total of 16 measurements. Using SCP and MCP, two three-dimensional (3D) images were acquired from each participant. All 3D measurements and direct measurements were measured twice by the same operator to assess intraexaminer repeatability. Intraclass coefficients (ICCs) were used to evaluate intraexaminer repeatability and interexaminer agreement of the methods. Nonparametric bootstrap analyses were used to compare the means of the measurements among the three methods.ResultsAll three methods showed excellent intraexaminer repeatability (ICCs > 0.90), except interpupillary distance (ICC = 0.86) measured by SCP. Both SCP and MCP showed excellent interexaminer agreement (ICCs > 0.90), except interpupillary distance (ICC = 0.79), left gonion-pogonion (ICC = 0.74), and columella-subnasale-labrale superior angle (ICC = 0.86) measured by SCP. Overall, there was good agreement between methods, except for columella-subnasale-labrale superior angle (ICC = 0.40) between SCP and MCP.ConclusionsBoth SCP and MCP techniques were found to be reliable and valid options for 3D facial imaging. SCP produced slightly larger mean values for several measurements, but the differences were within a clinically acceptable range. Because of the larger margin of errors, measurements including the gonial area and subnasale should be assessed with caution.     

高低角型男孩颅面部软组织侧貌水平向生长变化的纵向研究

目的：探讨高低角型男孩颅面部软组织侧貌在水平方向的生长变化。方法：根据Bjork前颅基底稳定结构重迭法,头影测量20名男孩在自然头势状态下9、12、15和18岁的X线头颅定位侧位片,然后,统计分析颅面部软组织侧貌Ga、N′、Nasal、Sn、A′、Ls、Li、B′、Pg及Gn各点至垂直平面(Pr-VER)的水平向距离变化以及上下唇至美学平面(E—line)的垂直距离变化。结果：1)高低角型男孩在9～18岁期间额部、鼻根部及唇部与鼻尖的水平距离随年龄增加而增加,而颏部与鼻尖水平距离虽有增加,但在某些阶段其距离反而缩短。2)高角型男孩Ga、N′、Nasal、Pg及Gn点到Pr水平距离其各阶段各测量值明显大于低角型,可唇部表现则不同,高角型唇部比低角型表现为更为前突。3)高角型颏部向前生长移动幅度小于低角型,而唇部向前生长幅度明显大于低角型。相对于美学平面,低角型上下唇在9～18岁期间后退幅度明显大于高角型。结论：高低角型男孩颅面部软组织侧貌生长变化存在显著差异,其主要区别在于唇部及颏部。这对正畸临床诊断与治疗具有借鉴作用。     

骨组织工程3D生物打印的研究进展

近几十年来,骨组织工程在骨缺损修复治疗的应用中获得了飞速的发展,而3D生物打印是近十年来在骨组织工程中一种非常具有前景的技术.传统骨组织工程支架制造方法无法精确控制空间结构,且在支架制作完成后接种细胞也无法控制细胞的均匀分布.尽管3D生物打印作为一类含细胞骨组织工程支架制造技术,以水凝胶类材料作为基础将细胞置入支架中,...     

Direct 3D Printing of Flexible Nasal Prosthesis: Optimized Digital Workflow from Scan to Fit

A maxillofacial prosthesis is a successful treatment modality to restore missing facial parts. Digital technologies and 3D printing are employed in constructing facial prostheses such as ears; however, their application is still partial, and final prostheses are usually manufactured conventionally using stone molds. This report aims to introduce a complete digital workflow to construct a nasal prosthesis and compare it to the conventional workflow of a patient requiring a nasal prosthesis. A computer tomography scan showing the defect was exported to specialized software to create 3D reconstructions of the patient's face and underlying bone. The nose was digitally designed restoring facial esthetics, anatomy, shape, and skin color. Different skin tones were digitally matched to skin tissues adjacent to the defect area using the Spectromatch system. The design was 3D printed in flexible and colorful material at 16 μm resolution using a 3D printer. External color pigmentations were applied to the nose for optimum esthetics, and the prosthetic nose was sealed in silicone and left to heat polymerize for 15 minutes. The prosthetic nose was retained in place using biomedical adhesive, and the patient was pleased with it. This report proposes a complete digital workflow to directly design and fabricate a prosthetic nose of acceptable esthetics. Such a workflow can lead to enhanced prosthesis reproducibility and acceptability and may become an effective treatment option for treatment of patients with facial defects.     

3dMD摄影测量系统辅助颅颌面软组织畸形整复的初步报道

目的:初步建立3dMD摄影测量系统在颅颌面软组织畸形整复中的技术方法,并探讨其在术前规划、术中指导、术后评价中的应用价值。方法:选取典型颅颌面先天性及获得性软组织缺损畸形病例各1例,术前应用3dMD系统设计手术范围,定性定量计算出患者软组织畸形的主要部位与程度,按照术前规划施行畸形整复手术,并评价其术后效果。结果:2例患者术后均达到较满意的面形,3dMD术前模拟手术计算所得软组织畸形量与术中实际需要量基本相符。结论:经初步临床实践,建立了3dMD摄影测量系统辅助颅颌面软组织畸形整复的技术方法,该系统可为颅颌面软组织畸形整复手术提供较准确的定性定量分析,具有一定的应用价值。     

多类型数字影像拟合及3D打印技术在髁突肿瘤中的运用

目的:探讨多类型数字影像拟合及3D打印技术在治疗髁突肿瘤中的临床意义.方法:基于患者螺旋CT数据,血管CTA数据,牙齿3D扫描数据,联合运用软件Mimics 21.0(Materialise,Belgium)重建患者上下颌骨、面部软组织、髁突肿瘤及周围重要解剖结构,并运用牙齿3 D扫描数据与螺旋CT上下颌骨牙齿数据拟合...     

Three dimensional CT reconstruction: a comparison between 2D, 3D CT and original anatomical structures

Conventional two dimensional computed tomography has provided significant advancement in clinical diagnosis with information on cross-sectional anatomy of various parts of the body. However, three dimensional representations are not directly available. This is now made possible by recent development of CAD software and CT equipments and technique such as multiplanar reformation capable of providing 3D reconstruction using 2D CT data. This article evaluates the accuracy of measurements and dimensions in 3D CT reconstruction.     

Optimization of 3D bioprinting of periodontal ligament cells

Three-dimensional (3D) bioprinting of cells is an emerging area of research but has been not explored yet in the context of periodontal tissue engineering.ObjectiveThis study reports on the optimisation of the 3D bioprinting of periodontal ligament cells for potential application in periodontal regeneration.MethodsWe systematically investigated the printability of various concentrations of gelatin methacryloyl (GelMA) hydrogel precursor using a microextrusion based three-dimensional (3D) printer. The influence of different printing parameters such as photoinitiator concentration, UV exposure, pressure and dispensing needle diameter on the viability of periodontal ligament cells encapsulated within the 3D bioprinted construct were subsequently assessed.ResultsThis systematic evaluation enabled the selection of the most suited printing conditions for achieving high printing resolution, dimensional stability and cell viability for 3D bioprinting of periodontal ligament cells.SignificanceThe optimised bioprinting system is the first step towards to the reproducible manufacturing of cell laden, space maintaining scaffolds for the treatment of periodontal lesions.