数字化口内扫描技术专家共识

Expert consensus on digital intraoral scanning technology

摘要

数字化口内扫描是近年口腔数字化技术的研究热点，成为口腔正畸、修复、种植的重要技术。数字化口内扫描的精确度和数据资料采集拼接的准确性是保证数字印模成功和加工制作效果的关键；而扫描仪特性、成像原理以及操作者扫描方式、扫描对象、口腔组织特殊性、修复设计方案等均会影响数据采集的准确性。仍有诸多操作者对于如何鉴别不同修复设计的扫描策略、扫描轨迹、如何减少数字化扫描误差等认识不足，且目前国内外学者关于数字化口内扫描技术尚未形成统一标准与共识。为了更好地帮助操作者应对口内扫描中遇到的难题，提高数字化扫描质量，本文集合了参与专家的共同意见，通过对现有证据的归纳鉴别，阐述数字化口内扫描误差的原因与应对方法，掌握不同口腔印模需求下的扫描策略。本专家共识认为，基于影响数字化口内扫描精度及扫描图像重现效果受诸多因素的影响，采用正确的扫描轨迹可缩短临床操作时间，提高扫描的精确性，扫描轨迹主要包括E字法、分段法和S型法等。①进行固定义齿修复时，建议先扫描基牙及前后两个邻牙，再把基牙区域挖出洞型，最后在基牙预备完成后补扫洞型缺口处，既可满足临床实际需求，同时也能得到最可靠的精度。②全口无牙颌行全口义齿修复时，在牙槽嵴底黏膜组织设定标记点、一次性捕获前庭区域的图像、采用不同类型的扫描路径如“Z”形、“S”形、颊腭、腭颊路径、分段扫描牙弓等策略，可以减少扫描误差和改善图像拼接以及重叠的问题。③对于种植修复，当进行种植体支持的单冠修复与小跨度上部结构修复时，建议先预扫所需牙弓，再把基牙区域挖出洞型，最后安装好种植扫描杆后再补扫洞型缺口处；当进行骨水平种植体冠修复时，可通过改良的间接扫描方法，将扫描过程分为三步：首先在口内扫描临时修复体和相邻两个牙位的牙齿与牙龈组织，然后在种植体上安装标准扫描杆并扫描全牙弓，最后在口外扫描临时修复体，以获取种植体颈部穿龈轮廓的三维形态，从而增加种植体周软组织扫描的稳定性，提高扫描还原度；对于牙列缺失种植固定桥修复，黏膜具有活动度增加了扫描难度，扫描仪难以分辨形态大小相同的扫描杆，易造成图像叠加错误，可以通过更改扫描杆的几何形状改变光学曲率半径，获得更高的种植数字化印模精确度。共识认为，随着扫描牙弓的范围越大，数据拼接次数增加，扫描精度随之下降；尤其是行全口种植修复印模时，由于口内存在不稳定、不平整的黏膜形态，且无相对明显、固定的参照物，易增加图像拼接处理的难度，造成精度不足，针对此类进行修复设计时，应谨慎选择数字化口内扫描方式获取模型数据，在缺失牙大于5颗时不宜使用数字化印模。

Abstract

Digital intraoral scanning is a hot topic in the field of oral digital technology. In recent years, digital intraoral scanning has gradually become the mainstream technology in orthodontics, prosthodontics, and implant dentistry. The precision of digital intraoral scanning and the accuracy and stitching of data collection are the keys to the success of the impression. However, the operators are less familiar with the intraoral scanning characteristics, imaging processing, operator scanning method, oral tissue specificity of the scanned object, and restoration design. Thus far, no unified standard and consensus on digital intraoral scanning technology has been achieved at home or abroad. To deal with the problems encountered in oral scanning and improve the quality of digital scanning, we collected common expert opinions and sought to expound the causes of scanning errors and countermeasures by summarizing the existing evidence. We also describe the scanning strategies under different oral impression requirements. The expert consensus is that due to various factors affecting the accuracy of digital intraoral scanning and the reproducibility of scanned images, adopting the correct scanning trajectory can shorten clinical operation time and improve scanning accuracy. The scanning trajectories mainly include the E-shaped, segmented, and S-shaped methods. When performing fixed denture restoration, it is recommended to first scan the abutment and adjacent teeth. When performing fixed denture restoration, it is recommended to scan the abutment and adjacent teeth first. Then the cavity in the abutment area is excavated. Lastly, the cavity gap was scanned after completing the abutment preparation. This method not only meets clinical needs but also achieves the most reliable accuracy. When performing full denture restoration in edentulous jaws, setting markers on the mucosal tissue at the bottom of the alveolar ridge, simultaneously capturing images of the vestibular area, using different types of scanning paths such as Z-shaped, S-shaped, buccal-palatal and palatal-buccal pathways, segmented scanning of dental arches, and other strategies can reduce scanning errors and improve image stitching and overlap. For implant restoration, when a single crown restoration is supported by implants and a small span upper structure restoration, it is recommended to first pre-scan the required dental arch. Then the cavity in the abutment area is excavated. Lastly, scanning the cavity gap after installing the implant scanning rod. When repairing a bone level implant crown, an improved indirect scanning method can be used. The scanning process includes three steps: First, the temporary restoration, adjacent teeth, and gingival tissue in the mouth are scanned; second, the entire dental arch is scanned after installing a standard scanning rod on the implant; and third, the temporary restoration outside the mouth is scanned to obtain the three-dimensional shape of the gingival contour of the implant neck, thereby increasing the stability of soft tissue scanning around the implant and improving scanning restoration. For dental implant fixed bridge repair with missing teeth, the mobility of the mucosa increases the difficulty of scanning, making it difficult for scanners to distinguish scanning rods of the same shape and size, which can easily cause image stacking errors. Higher accuracy of digital implant impressions can be achieved by changing the geometric shape of the scanning rods to change the optical curvature radius. The consensus confirms that as the range of scanned dental arches and the number of data concatenations increases, the scanning accuracy decreases accordingly, especially when performing full mouth implant restoration impressions. The difficulty of image stitching processing can easily be increased by the presence of unstable and uneven mucosal morphology inside the mouth and the lack of relatively obvious and fixed refer

关键词

数字化 / 扫描 / 口内扫描 / 数字化技术 / 数字化口内扫描 / 精确度 / 修复 / 种植

Key words

digitization / scanning / intraoral scanning / digital technology / digital intraoral scanning / accuracy / prosthodontics / implant dentistry