We present a fully automated method of integrating intraoral scan (IOS) and dental cone-beam computerized tomography (CBCT) images into one image by complementing each image's weaknesses. Dental CBCT alone may not be able to delineate precise details of the tooth surface due to limited image resolution and various CBCT artifacts, including metal-induced artifacts. IOS is very accurate for the scanning of narrow areas, but it produces cumulative stitching errors during full-arch scanning. The proposed method is intended not only to compensate the low-quality of CBCT-derived tooth surfaces with IOS, but also to correct the cumulative stitching errors of IOS across the entire dental arch. Moreover, the integration provide both gingival structure of IOS and tooth roots of CBCT in one image. The proposed fully automated method consists of four parts; (i) individual tooth segmentation and identification module for IOS data (TSIM-IOS); (ii) individual tooth segmentation and identification module for CBCT data (TSIM-CBCT); (iii) global-to-local tooth registration between IOS and CBCT; and (iv) stitching error correction of full-arch IOS. The experimental results show that the proposed method achieved landmark and surface distance errors of 112.4 $\mu$m and 301.7 $\mu$m, respectively.

翻译：我们提出一种全自动方法，通过互补口腔扫描（IOS）与牙科锥形束计算机断层扫描（CBCT）影像的各自缺陷，将其整合为单一影像。单独使用牙科CBCT因影像分辨率有限及各类CBCT伪影（包括金属伪影）而无法精确描绘牙齿表面细节。IOS在狭窄区域扫描时精度极高，但在全牙弓扫描过程中会产生累积性拼接误差。本方法旨在不仅通过IOS补偿CBCT所得牙面质量不足，还矫正IOS在全牙弓范围内的累积拼接误差。此外，整合后可在同一影像中同时呈现IOS的牙龈结构及CBCT的牙根结构。所提出的全自动方法由四部分组成：（i）IOS数据单颗牙齿分割与识别模块（TSIM-IOS）；（ii）CBCT数据单颗牙齿分割与识别模块（TSIM-CBCT）；（iii）IOS与CBCT间的全局到局部牙齿配准；（iv）全牙弓IOS拼接误差校正。实验结果表明，本方法实现了标志点距离误差112.4微米和表面距离误差301.7微米。