title: Accuracy of three-dimensional printing for manufacturing replica teeth.
abstract: OBJECTIVE
  Three-dimensional (3D) printing is a recent technological development that may play a significant role in orthodontic diagnosis and treatment. It can be used to fabricate skull models or study models, as well as to make replica teeth in autotransplantation or tooth impaction cases. The aim of this study was to evaluate the accuracy of fabrication of replica teeth made by two types of 3D printing technologies.
  
  
  METHODS
  Fifty extracted molar teeth were selected as samples. They were scanned to generate high-resolution 3D surface model stereolithography files. These files were converted into physical models using two types of 3D printing technologies: Fused deposition modeling (FDM) and PolyJet technology. All replica teeth were scanned and 3D images generated. Computer software compared the replica teeth to the original teeth with linear measurements, volumetric measurements, and mean deviation measurements with best-fit alignment. Paired t-tests were used to statistically analyze the measurements.
  
  
  RESULTS
  Most measurements of teeth formed using FDM tended to be slightly smaller, while those of the PolyJet replicas tended to be slightly larger, than those of the extracted teeth. Mean deviation measurements with best-fit alignment of FDM and PolyJet group were 0.047 mm and 0.038 mm, respectively. Although there were statistically significant differences, they were regarded as clinically insignificant.
  
  
  CONCLUSIONS
  This study confirms that FDM and PolyJet technologies are accurate enough to be usable in orthodontic diagnosis and treatment.
authors.affiliation: Department of Orthodontics, Wonkwang University Daejeon Dental Hospital, Daejeon, Korea.
authors.forename: Keun-Young
authors.initials: KY
authors.lastname: Lee
authors.affiliation: Department of Orthodontics, Wonkwang University Daejeon Dental Hospital, Daejeon, Korea.
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Cho
authors.affiliation: Department of Orthodontics, Wonkwang University Daejeon Dental Hospital, Daejeon, Korea.
authors.forename: Na-Young
authors.initials: NY
authors.lastname: Chang
authors.affiliation: Department of Orthodontics, Wonkwang University Daejeon Dental Hospital, Daejeon, Korea.
authors.forename: Jong-Moon
authors.initials: JM
authors.lastname: Chae
authors.affiliation: Department of Orthodontics, Wonkwang University Dental Hospital, Iksan, Korea.
authors.forename: Kyung-Hwa
authors.initials: KH
authors.lastname: Kang
authors.affiliation: Department of Orthodontics, Wonkwang University Dental Hospital, Iksan, Korea.
authors.forename: Sang-Cheol
authors.initials: SC
authors.lastname: Kim
authors.affiliation: Department of Orthodontics, Wonkwang University Sanbon Dental Hospital, Sanbon, Korea.
authors.forename: Jin-Hyoung
authors.initials: JH
authors.lastname: Cho
keywords: Orthodontics; Three-dimensional printing; Tooth