title: Individual tooth segmentation from CT images scanned with contacts of maxillary and mandible teeth.
abstract: OBJECTIVE
  Tooth segmentation from computed tomography (CT) images is a fundamental step in generating the three-dimensional models of tooth for computer-aided orthodontic treatment. Individual tooth segmentation from CT images scanned with contacts of maxillary and mandible teeth is especially challenging, and no method has been reported previously. This study aimed to develop a method for individual tooth segmentation from these images.
  
  
  METHODS
  Tooth contours of maxilla and mandible are first segmented from the volumetric CT images slice-by-slice. For each slice, a line is extracted using the Radon transform to separate neighboring teeth, and each tooth contour is then segmented by a level set model from the corresponding side of the line. Then, each maxillary tooth whose contours overlap with that of mandible ones is detected, and a mesh model is reconstructed from all the contours of these maxillary and mandible teeth with contour overlap. The reconstructed mesh model is segmented using threshold and fast marching watershed method to separate the touched maxillary and mandible teeth. Finally, the separated tooth models are restored to fill the holes to obtain complete tooth models. The proposed method was tested on CT images of ten subjects scanned with natural contacts of maxillary and mandible teeth.
  
  
  RESULTS
  For all the tested images, individual tooth regions are extracted successfully, and the segmentation accuracy and efficiency of the proposed method is promising.
  
  
  CONCLUSIONS
  The proposed method is effective to segment individual tooth from CT images scanned with contacts of maxillary and mandible teeth.
authors.affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Shenzhen, China. Electronic address: zy.xia@siat.ac.cn.
authors.forename: Zeyang
authors.initials: Z
authors.lastname: Xia
authors.affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Shenzhen, China.
authors.forename: Yangzhou
authors.initials: Y
authors.lastname: Gan
authors.affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
authors.forename: Lichao
authors.initials: L
authors.lastname: Chang
authors.affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China. Electronic address: jing.xiong@siat.ac.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Xiong
authors.affiliation: Shanghai Key Lab of Navigation and Location Services, and Department of Automation, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Qunfei
authors.initials: Q
authors.lastname: Zhao
mesh_terms: D006801:Humans; D008334:Mandible / Q000000981:diagnostic imaging*; D008437:Maxilla / Q000000981:diagnostic imaging*; D003765:Models, Dental; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014070:Tooth / Q000000981:diagnostic imaging*
keywords: Computed tomography images; Level set method; Mesh segmentation; Radon transform; Tooth segmentation