title: Micro-sized erosions in a nanofilled composite after repeated acidic beverage exposures: consequences of clusters dislodgments.
abstract: OBJECTIVE
  To evaluate the hardness (KHN), color stability (DE), and superficial micromorphology of two categories of composites after immersion in either distilled water or grape juice for up to 45 days.
  
  
  METHODS
  Cylindrical specimens (6 mm diameter x 2 mm thick) were obtained according to the factors: composite [Opallis (FGM) and Filtek Z350XT (3M ESPE)]; immersion solution (distilled water and grape juice); and evaluation time: 24 h and 7, 14, 21, 28, and 45 days. After photoactivation, the specimens were stored at 37 ºC for 24 h. KHN (50 g/15 s) and ΔE were then repeatedly assessed according to the immersion solutions. Data were analyzed (three-way ANOVA/Tukey's test). Scanning electron microscopy (SEM) topographic analysis was also performed.
  
  
  RESULTS
  In general, KHN of both composites reduced after 24 h, irrespective of the immersion solution and time. A significantly lower KHN was noted for Opallis compared with Filtek Z350XT in all parameters. An increase in ΔE over time was noted for both composites, irrespective of the immersion solution. Significantly higher ΔE was noted for Filtek Z350XT immersed in grape juice compared with Opallis, regardless of the evaluation time. The grape juice caused significantly higher DE compared with water in all periods. SEM analysis showed eroded areas for Filtek Z350XT but not for Opallis.
  
  
  CONCLUSIONS
  The compositions and immersion solutions influence the composite hardness and the color stability. In spite of the higher hardness, the nanofilled composite is more susceptible to color change than the microhybrid when immersed in an acidic dyed solution.
authors.affiliation: Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Nádia da Rocha
authors.initials: Nda R
authors.lastname: Svizero
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Adriana Regina Cruz Grando de
authors.initials: AR
authors.lastname: Góes
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Tamires de Luccas
authors.initials: Tde L
authors.lastname: Bueno
authors.affiliation: Biomaterials Research Group, Universidade Anhanguera de São Paulo, São Paulo, SP, Brazil.
authors.forename: Vinicius
authors.initials: V
authors.lastname: Di Hipólito
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Linda
authors.initials: L
authors.lastname: Wang
authors.affiliation: Biomaterials Research Group, Universidade Anhanguera de São Paulo, São Paulo, SP, Brazil.
authors.forename: Paulo Henrique Perlatti
authors.initials: PH
authors.lastname: D'Alpino
mesh_terms: D000704:Analysis of Variance; D002253:Carbonated Beverages / Q000009:adverse effects*; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D006245:Hardness Tests; D007101:Immersion; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D013499:Surface Properties / Q000187:drug effects; D013997:Time Factors; D027843:Vitis; D014867:Water / Q000737:chemistry
chemical_list: D003188:Composite Resins; C533204:filtek Z350; D014867:Water