title: Reproducibility of different arrangement of resin copings by dental microstereolithography: Evaluating the marginal discrepancy of resin copings.
abstract: BACKGROUND
  Microstereolithography (μ-SLA), a form of additive manufacturing, can produce one or more platforms of resin copings. However, no evaluation has been made of the variation in marginal discrepancy using this method, even though this is an important factor for a successful restoration.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to evaluate the reproducibility and marginal discrepancy of resin copings fabricated using dental μ-SLA.
  
  
  METHODS
  A master die of a mandibular right first molar tooth was made from Type IV stone and scanned to produce a stereolithography file. Resin copings were then fabricated using μ-SLA additive manufacturing by repeating 1, 3, or 6 arrays to give a total number of 18. The marginal discrepancies of these resin copings were measured using digital microscopy (at ×160 magnification), and the data obtained were analyzed using a nonparametric Kruskal-Wallis H test, post hoc Mann-Whitney U-test, and Bonferroni correction.
  
  
  RESULTS
  The mean ±SD total marginal discrepancies of 1, 3, and 6 arrays were found to be 72.2 ±39.1 μm, 61.2 ±37.3 μm, and 92.5 ±54.1 μm. Statistically significant differences were found among the compared groups (P<.05).
  
  
  CONCLUSIONS
  Based on the marginal discrepancy, μ-SLA of additive manufacturing is more precise when 3 arrays are used than when 1 or 6 arrays are used on a single build platform. Because the fit is affected by the number of copings fabricated, further research of multiple resin copings is required.
authors.affiliation: Doctoral student, Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: Dong-Yeon
authors.initials: DY
authors.lastname: Kim
authors.affiliation: Assistant Professor, Department of Dental Technology, Medical Campus, KyungDong University, Gangwon-do, Republic of Korea.
authors.forename: Jin-Hun
authors.initials: JH
authors.lastname: Jeon
authors.affiliation: Professor, Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: Ji-Hwan
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Associate Professor, Department of Dental Laboratory Science and Engineering, College of Health Science, Department of Public Health Sciences, Graduate School, and BK21+ Program in Public Health Sciences, Korea University, Seoul, Republic of Korea.
authors.forename: Hae-Young
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Professor, Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea. Electronic address: kuc2842@korea.ac.kr.
authors.forename: Woong-Chul
authors.initials: WC
authors.lastname: Kim
mesh_terms: D003761:Dental Impression Technique; D018772:Dental Marginal Adaptation; D006801:Humans; D008963:Molar / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012117:Resins, Synthetic / Q000627:therapeutic use*; D000076227:Stereolithography
chemical_list: D012117:Resins, Synthetic