基于口腔计算机断层扫描图像与激光扫描图像融合的牙齿三维模型重构

Three-dimensional tooth model reconstruction based on fusion of dental computed tomography images and laser-scanned images

完整牙齿三维模型为正畸医师进行错颌畸形诊断、治疗方案规划提供了必要的辅助信息。目前,牙齿三维模型主要通过口腔计算机断层扫描(CT)图像分割与重构得到。然而,利用CT图像重构的模型精度较低,不适用于无托槽隐形矫治器的辅助设计;另一方面,在正畸治疗的不同周期对患者进行重复口腔CT扫描会给患者带来辐射伤害。为此,本文提出基于口腔CT图像与激光扫描图像融合重构牙齿三维模型的方法。该方法利用口腔CT图像重构的牙根与激光扫描图像重构的牙冠经配准融合后建立完整的牙齿三维模型,所建立的模型牙冠部位精度更高。同时,该方法只需在正畸治疗前对患者进行一次口腔CT扫描,在治疗过程中进行激光扫描即可得到患者各治疗周期完整的牙列模型,从而通过减少CT扫描次数降低给患者带来的辐射伤害。

Complete three-dimensional （3D） tooth model provides essential information to assist orthodontists for diagnosis and treatment planning. Currently, 3D tooth model is mainly obtained by segmentation and reconstruction from dental computed tomography （CT） images. However, the accuracy of 3D tooth model reconstructed from dental CT images is low and not applicable for invisalign design. And another serious problem also occurs, i.e. frequentative dental CT scan during different intervals of orthodontic treatment often leads to radiation to the patients. Hence, this paper proposed a method to reconstruct tooth model based on fusion of dental CT images and laser-scanned images. A complete 3D tooth model was reconstructed with the registration and fusion between the root reconstructed from dental CT images and the crown reconstructed from laser-scanned images. The crown of the complete 3D tooth model reconstructed with the proposed method has higher accuracy. Moreover, in order to reconstruct complete 3D tooth model of each orthodontic treatment interval, only one pre-treatment CT scan is needed and in the orthodontic treatment process only the laser-scan is required. Therefore, radiation to the patients can be reduced significantly.