title: Three-dimensional analysis of marginal and internal fit of copings fabricated with polyetherketoneketone (PEKK) and zirconia.
abstract: OBJECTIVE
  The purpose of this in vitro study was to compare and analyze the three-dimensional marginal and internal fit of PEKK and zirconia copings.
  
  
  METHODS
  Two acrylic models of the right maxillary canine, first molar were fabricated as master dies and duplicated by one-step dual viscosity impressions. Five stone replicas from each model were digitized with a blue-light scanner and copings were machined from Pekkton and Zirconia blanks. The inner surface of all the copings and two original acrylic models were digitized by a highly accurate optical scanner. By superimposing the digitized coping data with the CAD-reference die three-dimensionally, visual fit-discrepancies were drawn by calculating the root mean square (RMS) and visualized on a color-difference map. Each calculated RMS-value was statistically analyzed by 3-way ANOVA. In addition, Student's t-test was conducted in order to verify the significance (α=.05) of fit-discrepancies based on the type of abutment tooth and the materials.
  
  
  RESULTS
  Mean RMS-values for marginal fit (internal fit) ranged from 51.64±1.5 (36.12±1.34) to 69.62±8.11 (41.6±1.63)μm. Differences in marginal fit (canine: P=.001; molar: P=.047) and internal fit (canine: P=.017; molar: P=.046) were statistically significant. The results of the 3-way ANOVA showed statistically significant differences in the RMS values of the two groups for the material (P<.001), the types of the abutment tooth (P<.001), and the measured region (P<.001).
  
  
  CONCLUSIONS
  The marginal and internal fit of both PEKK and zirconia copings of both canine and molar were within the clinically acceptable range. However, the PEKK presented better fitness compared with the zirconia.
authors.affiliation: Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: So-Yeon
authors.initials: SY
authors.lastname: Bae
authors.affiliation: Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: Il-Do
authors.initials: ID
authors.lastname: Jeong
authors.affiliation: Department of Public Health Science, Graduate School & BK21+Program in Public Health Sciences, Korea University, Seoul, Republic of Korea.
authors.forename: Hae-Young
authors.initials: HY
authors.lastname: Kim
authors.affiliation: 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: 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: D017076:Computer-Aided Design; D003442:Crowns; D003481:Cuspid; D059605:Dental Implant-Abutment Design / Q000379:methods*; D003761:Dental Impression Technique; D018772:Dental Marginal Adaptation; D003764:Dental Materials; D017267:Dental Prosthesis Design / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007659:Ketones; D003765:Models, Dental; D008963:Molar; D015040:Zirconium
chemical_list: D003764:Dental Materials; D007659:Ketones; D015040:Zirconium; C028541:zirconium oxide
keywords: Internal fit; Marginal fit; PEKK; Three-dimensional analysis; Zirconia