title: Effects of surface treatments on the translucency, opalescence, and surface texture of dental monolithic zirconia ceramics.
abstract: BACKGROUND
  Surface polishing or glazing may increase the appearance of depth of monolithic zirconia restorations.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to investigate the effects of surface treatments on the translucency, opalescence, and surface texture of dental monolithic zirconia ceramics.
  
  
  METHODS
  Forty-five monolithic zirconia specimens (16.3×16.4×2.0 mm) were divided into groups I to V, according to the number of colorings each received. Each group was then divided into 3 subgroups (n=3) according to the surface treatment: N=no treatment; P=polished; and G=glazed. CIElab color coordinates were obtained relative to D65 on a reflection spectrophotometer. The translucency parameter (TP) and opalescence parameter (OP) were calculated. One specimen per subgroups I and V was selected for evaluation of surface roughness (Ra) and was examined with scanning electron microscopy (SEM). Data were analyzed with 2-way ANOVA and pairwise comparisons (α=.05). Statistical powers were verified to evaluate results (α=.05).
  
  
  RESULTS
  The interaction effects of surface treatments combined with the number of colorings were significant for TP, OP, and Ra (P<.001), as follows: Ra=partial eta squared [ηp(2)]=.928; OP ηp(2)=.184; and TP ηp(2)=.144. No significant differences between TP were found among surface treatments in most groups (P>.05), whereas glazing significantly decreased OP and Ra in most groups. SEM images demonstrated that surface treatments affected the surface texture of monolithic zirconia ceramics.
  
  
  CONCLUSIONS
  Surface treatments combined with coloring strongly affect the surface texture of dental monolithic zirconia ceramics.
authors.affiliation: Clinical Associate Professor, Comprehensive Treatment Center, Seoul National University Dental Hospital, Seoul, Korea.
authors.forename: Hee-Kyung
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Professor, Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University, Jongno-gu, Seoul, Korea. Electronic address: ksh1250@snu.ac.kr.
authors.forename: Sung-Hun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Professor, Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University, Jongno-gu, Seoul, Korea.
authors.forename: Jai-Bong
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Clinical Assistant Professor, Department of Dentistry, Ajou University School of Medicine, Gyeong Gi-do, Korea.
authors.forename: Seung-Ryong
authors.initials: SR
authors.lastname: Ha
mesh_terms: D002516:Ceramics / Q000737:chemistry* / Q000627:therapeutic use; D003764:Dental Materials / Q000737:chemistry* / Q000627:therapeutic use; D003775:Dental Polishing; D066298:In Vitro Techniques; D000068897:Iridescence; D008027:Light; D013499:Surface Properties; D015040:Zirconium / Q000737:chemistry* / Q000627:therapeutic use
chemical_list: D003764:Dental Materials; D015040:Zirconium; C028541:zirconium oxide