title: A novel computer-aided method to fabricate a custom one-piece glass fiber dowel-and-core based on digitized impression and crown preparation data.
abstract: OBJECTIVE
  Fiber-reinforced composite dowels have been widely used for their superior biomechanical properties; however, their preformed shape cannot fit irregularly shaped root canals. This study aimed to describe a novel computer-aided method to create a custom-made one-piece dowel-and-core based on the digitization of impressions and clinical standard crown preparations.
  
  
  METHODS
  A standard maxillary die stone model containing three prepared teeth each (maxillary lateral incisor, canine, premolar) requiring dowel restorations was made. It was then mounted on an average value articulator with the mandibular stone model to simulate natural occlusion. Impressions for each tooth were obtained using vinylpolysiloxane with a sectional dual-arch tray and digitized with an optical scanner. The dowel-and-core virtual model was created by slicing 3D dowel data from impression digitization with core data selected from a standard crown preparation database of 107 records collected from clinics and digitized. The position of the chosen digital core was manually regulated to coordinate with the adjacent teeth to fulfill the crown restorative requirements. Based on virtual models, one-piece custom dowel-and-cores for three experimental teeth were milled from a glass fiber block with computer-aided manufacturing techniques. Furthermore, two patients were treated to evaluate the practicality of this new method.
  
  
  RESULTS
  The one-piece glass fiber dowel-and-core made for experimental teeth fulfilled the clinical requirements for dowel restorations. Moreover, two patients were treated to validate the technique.
  
  
  CONCLUSIONS
  This novel computer-aided method to create a custom one-piece glass fiber dowel-and-core proved to be practical and efficient.
authors.affiliation: Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Chen
authors.forename: Ya
authors.initials: Y
authors.lastname: Li
authors.forename: Xuliang
authors.initials: X
authors.lastname: Deng
authors.forename: Xinzhi
authors.initials: X
authors.lastname: Wang
mesh_terms: D000328:Adult; D001641:Bicuspid / Q000033:anatomy & histology; D017076:Computer-Aided Design; D003442:Crowns; D003481:Cuspid / Q000033:anatomy & histology; D003760:Dental Impression Materials / Q000737:chemistry; D003761:Dental Impression Technique / Q000295:instrumentation; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D005260:Female; D005500:Follow-Up Studies; D005898:Glass / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007180:Incisor / Q000033:anatomy & histology; D003765:Models, Dental; D061848:Optical Imaging / Q000379:methods; D011176:Post and Core Technique / Q000295:instrumentation*; D018915:Root Canal Preparation / Q000379:methods; D019231:Tooth Preparation, Prosthodontic / Q000379:methods; D014584:User-Computer Interface
chemical_list: D003760:Dental Impression Materials; D003764:Dental Materials; C009753:fiberglass
keywords: CAD/CAM technique; optical 3D digitization; sectional dual-arch impression