title: Water Sorption, Solubility, and Color Stability of Giomer Restoratives.
abstract: OBJECTIVE
  This study compared the color stability, water sorption, and solubility of a giomer composite and two nanohybrid composite resins.
  
  
  METHODS
  Disc-shaped specimens (1-mm thickness × 15-mm diameter) of a giomer (Beautifil II, Shofu, Kyoto, Japan) and two nanohybrid (Filtek Z550, 3M ESPE, St. Paul, MN, USA; Tetric N-Ceram, Ivoclar Vivadent, Schaan, Liechtenstein) composites (N = 10) were prepared. Baseline color measurements were taken, and specimens were immersed in water for 28 days. Following immersion, color values were remeasured, and color-change values (ΔE) were calculated. Water sorption and solubility were assessed by mass gain or loss after storage in water for 28 days. Data were analyzed with one-way analysis of variance and Tukey's post-hoc tests (p = 0.05). Pearson's correlation test was used to assess possible correlations between water sorption and solubility, water sorption and color stability, and solubility and color stability (p = 0.05).
  
  
  RESULTS
  Water sorbtion (%) and color change (ΔE) varied significantly among groups, with Beautifil II exhibiting the highest values (p < 0.001). No statistically significant differences were observed in water solubility values among the groups (p = 0.661); however, a linear, positive correlation was detected between solubility and discoloration (r = 0.368, p = 0.046).
  
  
  CONCLUSIONS
  Water sorption and discoloration values of the giomer composite group were significantly higher than those of the nanohybrids tested.
  
  
  CONCLUSIONS
  The high levels of water sorption and discoloration of giomer composites are likely to have an adverse effect on esthetic restorations.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Nihan
authors.initials: N
authors.lastname: Gonulol
authors.affiliation: Department of Pediatric Dentistry, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Sezin
authors.initials: S
authors.lastname: Ozer
authors.affiliation: Department of Pediatric Dentistry, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Emine
authors.initials: E
authors.lastname: Sen Tunc
mesh_terms: D003116:Color; D003793:Dental Restoration, Permanent; D008422:Materials Testing; D012995:Solubility; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water