title: Impact of surface roughness of gypsum materials on adaptation of zirconia cores.
abstract: OBJECTIVE
  The present study investigated the influences of various gypsum materials on the precision of fit of CAD/CAM-fabricated prostheses and analyzed their correlation with surface roughness.
  
  
  METHODS
  The master model of the mandibular right first molar was replicated, and four experimental groups based on two types of Type IV stone (GC Fujirock EP, Die keen) and two types of scannable stone (Aesthetic-Basegold, Everest Rock) were created to include a total of 40 specimens, 10 in each group. The surface roughness of the working models for the respective experimental groups was measured. Once the zirconia cores had been fabricated, the marginal and internal fits were measured with a digital microscope using the silicone replica technique. The mean and standard deviation of the respective points of measurement were computed and analyzed through the one-way ANOVA and Tukey's HSD test. The correlation between surface roughness and the precision of fit of the zirconia core was analyzed using the Pearson correlation analysis (α=.05).
  
  
  RESULTS
  The zirconia cores fabricated from the scannable stone working models exhibited a superior precision of fit as compared to those fabricated from the Type IV stone working models. The correlation analysis results showed a clear positive correlation between surface roughness and the precision of fit of zirconia cores in all of the experimental groups (P<.05).
  
  
  CONCLUSIONS
  The results confirmed that the surface roughness of dental working models has a decisive influence on the precision of fit of zirconia cores.
authors.affiliation: Institute for Health Science, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: Ki-Baek
authors.initials: KB
authors.lastname: Kim
authors.affiliation: Institute for Health Science, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: Jae-Hong
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Dental Technology, School of Medical and Public Health, Kyungdong University, Goseong, Gangwondo, Republic of Korea.
authors.forename: Sa-Hak
authors.initials: SH
authors.lastname: Kim
keywords: Adaptation; Scannable stone; Surface roughness; Type IV stone; Zirconia core