摄影测量与传统印模技术制取牙列缺失种植修复印模精度的比较研究

目的:通过体外实验对比摄影测量与传统印模技术制取牙列缺失种植修复印模的精度。方法:选择1例2019年9月就诊于首都医科大学口腔医学院种植中心的74岁男性上颌牙列缺失患者的上颌石膏模型,其上含螺丝固位基台替代体8个。通过开窗夹板式印模复制该石膏模型,将复制模型作为参考模型。由同1名主治医师用两种方法制取参考模型种植体基台...     

口内三维扫描仪扫描精度的定量评价方法研究

目的通过建立口内三维扫描仪扫描精度的定量评价方法, 评价6种口内三维扫描仪的扫描精度, 明确扫描范围与扫描精度之间的变化规律。方法计算机辅助设计全牙列固定义齿预备体简化模型, 借助加工正确度为5 μm的数控机床, 使用7075铝合金制作实体模型5个, 用测量精度为0.7 μm的三坐标测量机检验加工偏差, 选取5个模型中加工偏差最小的模型作为后续口内三维扫描仪扫描精度定量评价的实体模型, 导出模型设计数据作为扫描精度定量评价真值。6种口内三维扫描仪采用相同扫描路径扫描实体模型各10次, 共获得60个数字模型。导入Geomagic Studio 2014软件中, 提取数字模型肩台外缘线以上预备体, 分为单冠组、三单位组、五单位组、全牙列组, 分别与设计数据配准以及组内两两配准, 进行三维偏差分析, 计算扫描精度(包括扫描正确度与精密度)。结果 6种口内三维扫描仪单冠组、三单位组、五单位组和全牙列组的扫描正确度中位数范围分别为13.3～29.6、15.4～30.9、17.0～66.1和24.0～107.9 μm, 扫描精密度中位数范围分别为7.6～20.7、8.7～26.5、11.3～44....     

种植修复口内扫描印模精度的影响因素

在种植修复领域中,随着数字化技术逐渐推广,口内扫描印模因其简捷高效、舒适度高、便于医患交流的优势,临床应用日益广泛。但是在实际应用中,口内扫描印模的精度会受到多种因素的影响,包括扫描技术、牙列和种植体的情况、辅助标记和材料以及环境等,进而导致精度的降低,限制其适用性;应用于牙齿缺失较多的患者时可能会精度不足,建议当种植体数量多、间距大时谨慎使用口内扫描,不要过度拧紧扫描杆,尽量维持合适的环境条件。本文回顾近期相关研究文献,对种植修复中口内扫描印模精度的影响因素进行综述。     

牙种植义齿修复开窗式印模的护理配合

目的探讨牙种植义齿修复开窗式印模的护理配合。方法34例牙种植体修复时选择开窗式印模的患者,采用统一规范的操作程序,观察二次印模的精确性,转移体有无松动、移位,义龈制作是否标准,翻制的石膏工作模型是否清晰准确,替代体有无松动。结果除2例需要重新印模外,32例印模光滑、清晰、元气泡、义龈制作标准,翻制的石膏工作模型清晰完整,替代体无松动。成功率94．12％。结论熟悉医生的操作流程,掌握印模材料及义龈制作材料的性能、操作方法,才能做到护理配合规范、熟练、主动,取得精确的模型。     

牙列缺失开口与闭口式印模三维形态对比研究

目的:研究全口义齿开口与闭口式印模不同印模材料与取模方式对印模三维形态的影响。方法:无牙颌患者7例,分别取红膏藻酸盐印模、个别托盘印模与闭口式印模并灌制模型。光学扫描仓获得三组石膏模型数据转换为STL.导入Geomagic Control 2014配准后统计分析,评价模型配准是否与临床相符。结果:配准正确值主要分布上颌硬区、主承托区与副承托区,上颌翼缘封闭区存在显著性差异(P<0.01),下颌舌侧翼缘区存在差异(P<0.05)。结论:开口与闭口式印模三维形态的差异主要集中在上颌颊侧翼缘区与下颌舌侧翼缘区,红膏藻酸盐印模边缘更易伸展,是否有咬合压力并未对主承托区、副承托区三维形态带来显著影响。     

数字化印模在口腔种植修复中的研究进展

数字化印模是指使用口内扫描仪在患者口内无需直接接触即获取组织图像,并合成三维牙列影像的印模技术。数字化印模于口腔种植修复中的应用近年来开始受到关注,但其印模精度尚不明确,尤其是多颗种植体的数字化印模精度。本文详细介绍数字化印模的原理、在种植修复不同类型牙列缺损或缺失情况下的精度以及影响精度的相关因素,以期为数字化印模在种植修复中的临床应用提供参考依据。     

种植修复数字化口内印模及其精度的影响因素

数字化口内印模技术已经是临床常用的印模方式,并被用于种植修复领域.基于数字化的种植修复口内印模技术相较于传统种植修复取模具有许多优势,该文介绍数字化种植印模技术流程和分类,并对相关文献中口内扫描仪及种植扫描杆相关因素对种植数字化印模精度的影响进行综述分析,以期为临床应用提供指导.     

三种牙颌模型扫描仪牙尖交错牙合三维重建精度评价

目的：定量评价3种商品化三维光学牙颌模型扫描仪全牙列模型牙尖交错（牙合）（intercuspal occlusion, ICO）三维重建精度,为临床选择应用提供参考.方法：用超硬石膏灌制一副标准上下颌牙列石膏模型,咬合蜡固定ICO空间位置关系,在模型上确定45个特征点并顺序编号.分别选取上下颌模型上特征点进行配对,测量特征点对间距离Z.用机械接触式柔性测量机械臂R直接获取特征点空间坐标后软件测量获取参考值（ZR）;运用A（3Shape D700,3Shape A/S,丹麦）,B（ZENO@Scan,Weiland,德国）、C（Activity102,Smart Optics,德国）3种牙颌模型扫描仪重建全牙列模型牙尖交错骀后,人机交互选取模型对应特征点、软件测量获取测量值（Zn：ZA、ZB、Zc）.定义测量误差△Zn=Zn-ZR.采用配对￡检验比较Zn与ZR的差异,采用单因素方差分析对△Zn进行分析,比较3种牙颌模型之间的差异.结果：B扫描仪测量值与参考值差异有统计学意义,P＜ 0.05.3种商品化三维光学牙颌模型扫描仪模型牙尖交错（牙合）重建精度分别为：0.00＆#177;0.43mm,0.26＆#177;0.36mm,0.08＆#177;0.34mm.A、B扫描仪模型ICO三维重建精度差异有统计学意义,P＜0.05.结论：模型ICO三维重建正确度：A＞C＞B,精密度：C＞B＞A.     

口内数字化扫描仪辅助重建下颌第一磨牙髓腔固位冠修复三维有限元模型研究

目的    将口内数字化扫描仪创新性应用于三维有限元研究,探索出一种更为准确高效的牙体及其修复体的有限元建模方式。方法    利用Trios口内数字化扫描仪及锥形束CT（CBCT）采集志愿者口内预备后牙体的原始图像数据,然后采用计算机辅助设计（CAD）系统设计制作修复体表面模型,于有限元软件Mimics10.0中建立牙体表面模型,最终在ANSYS 14.0软件中完成两部分模型的整合得到实体模型。结果　本研究基于口内扫描仪及CBCT数据建立了真实而准确的下颌第一磨牙髓腔固位冠修复的三维有限元模型,共有单元格数25 776,节点数44 728,有限元模型与天然牙体同一层面近远中径及颊舌径所测得偏差值仅为-0.28%和-0.27%,小于等于文献记载传统方式有限元建模的偏差值-0.28%。结论　通过将口内数字化扫描仪引入于三维有限元研究,探索出了一种创新性建模方法,可大为简化传统建模步骤,有效减少建模过程中的数据损失及人为因素所造成的误差。本研究所建模型与口内天然牙的几何相似度极高,精确度和通用性均优于传统建模方式,为后续的有限元分析（FEA）研究奠定了坚实基础。     

美学区多牙连续缺失种植修复的印模制备方法

美学区种植修复时,准确转移修复体穿龈轮廓至终印模对实现最终美学效果至关重要。美学区单牙种植修复的个性化印模已广泛应用,然而连续多牙种植修复的个性化印模相对复杂。本文列举了美学区多单位种植修复的个性化印模方法。通过对比初印模缺失或具备两种临床情况,提出推荐分次印模分别转移种植体位置与复制穿龈轮廓的建议。     

Comparison of accuracy between digital and conventional implant impressions: two and three dimensional evaluations

PURPOSEThe present study compared the accuracy between digital and conventional implant impressions.MATERIALS AND METHODSThe experimental models were divided into six groups depending on the implant location and the scanning span. Digital impressions were captured using the intraoral optical scanner TRIOS (3Shape, Copenhagen, Denmark). Conventional impressions were taken with the monophase impression material based on addition-cured silicones, Honigum-Mono (DMG, Hamburg, Germany). A high-precision laboratory scanner D900 (3Shape, Copenhagen, Denmark) was used to obtain digital data of resin models and stone casts. Surface tessellation language (STL) datasets from scanner were imported into the analysis software Geomagic Qualify 14 (3D Systems, Rock Hill, SC, USA), and scan body deviations were determined through two-dimensional and three-dimensional analyses. Each scan body was measured five times. The Sidak t test was used to analyze the experimental data.RESULTSImplant position and scanning distance affected the impression accuracy. For a unilateral arch implant and the mandible models with two implants, no significant difference was observed in the accuracy between the digital and conventional implant impressions on scan bodies; however, the corresponding differences for trans-arch implants and mandible with six implants were extremely significant (P<.001).CONCLUSIONFor short-span scanning, the accuracy of digital and conventional implant impressions did not differ significantly. For long-span scanning, the precision of digital impressions was significantly inferior to that of the traditional impressions.     

Trueness and precision of digital impressions obtained using an intraoral scanner with different head size in the partially edentulous mandible

Purpose

It remains unclear whether digital impressions obtained using an intraoral scanner are sufficiently accurate for use in fabrication of removable partial dentures. We therefore compared the trueness and precision between conventional and digital impressions in the partially edentulous mandible.

Accuracy of single crowns fabricated from ultrasound digital impressions

Objective

This in vitro study aimed to evaluate marginal and internal fit of single crowns produced from high-frequency ultrasound based digital impressions of teeth prepared with finish lines covered by porcine gingiva, in comparison with those obtained by optical scanners with uncovered finish lines.

上部结构材料对无牙下颌种植固定修复影响的三维有限元分析

目的:通过三维有限元方法探讨上部结构材料对无牙下颌种植固定修复生物力学的影响,为无牙颌修复治疗提供参考。方法:构建无牙下颌种植固定修复三维有限元模型,用6种牙科材料（纯钛、钴铬合金、金合金、氧化锆、聚醚醚酮及碳纤维增强聚醚醚酮）分别对种植上部结构进行赋值,得到6种模型,模拟斜向加载,对种植体、周围骨组织及上部结构进行应...     

In-vitro evaluation of marginal and internal fit of 3-unit monolithic zirconia restorations fabricated using digital scanning technologies

PURPOSEThis study aimed to compare the marginal and internal fit of 3-unit monolithic zirconia restorations that were designed by using the data obtained with the aid of intraoral and laboratory scanners.MATERIALS AND METHODSFor the fabrication of 3-unit monolithic zirconia restorations using impressions taken from the maxillary master cast, plaster cast was created and scanned in laboratory scanners (InEos X5 and D900L). The main cast was also scanned with different intraoral scanners (Omnicam [OMNI], Primescan [PS], Trios 3 [T3], Trios 4 [T4]) (n = 12 per group). Zirconia fixed partial dentures were virtually designed, produced from presintered block, and subsequently sintered. Marginal and internal discrepancy values (in µm) were measured by using silicone replica method under stereomicroscope. Data were statistically analyzed by using 1-way ANOVA and Kruskal Wallis tests (P<.05).RESULTSIn terms of marginal adaptation, the measurements on the canine tooth indicated better performance with intraoral scanners than those in laboratory scanners, but there was no difference among intraoral scanners (P<.05). In the premolar tooth, PS had the lowest marginal (86.9 ± 19.2 µm) and axial (92.4 ± 14.8 µm), and T4 had the lowest axio-occlusal (89.4 ± 15.6 µm) and occlusal (89.1 ± 13.9 µm) discrepancy value. In both canine and premolar teeth, the D900L was found to be the most marginally and internally inconsistent scanner.CONCLUSIONWithin the limits of the study, marginal and internal discrepancy values were generally lower in intraoral scanners than in laboratory scanners. Marginal discrepancy values of scanners were clinically acceptable (< 120 µm), except D900L.     

Full arch digital scanning systems performances for implant-supported fixed dental prostheses: a comparative study of 8 intraoral scanners

PurposeCompare the accuracy of intraoral digital impression in full-arch implant-supported fixed dental prosthesis acquired with eight different intraoral scanner (Ios).MethodsA polymethyl methacrylate acrylic model of an edentulous mandible with six scan-abutment was used as a master model and its dimensions measured with a coordinate measuring machine. Eight different Ios were used to generate digital impression: True Definition, Trios, Cerec Omnicam, 3D progress, CS3500, CS3600, Planmeca Emelard and Dental Wings. Fifteen digital impressions were made. A software called “Scan-abut” was developed to analyse and compare the digital impression with the master model, obtaining the scanning accuracy. The three-dimensional (3D) position and distance analysis were performed.ResultsMean value of the 3D position analysis showed that the True Definition (31 μm ± 8 μm) and Trios (32 μm ± 5 μm) have the best performance of the group. The Cerec Omnicam (71 μm ± 55 μm), CS3600 (61 μm ± 14 μm) have an average performance. The CS3500 (107 μm ± 28 μm) and Planmeca Emelard (101 μm ± 38 μm) present a middle-low performance, while the 3D progress (344 μm ± 121 μm) and Dental Wings (148 μm ± 64 μm) show the low performance. The 3D distance analysis showed a good linear relationship between the errors and scan-abutment distance only with the True Definition and CS3600.ConclusionsNot all scanners are suitable for digital impression in full-arch implant-supported fixed dental prosthesis and the weight of the output files is independent from the accuracy of the Ios.