title: Effect of Accelerated Artificial Aging on Translucency of Methacrylate and Silorane-Based Composite Resins.
abstract: OBJECTIVE
  Composite restorations must have tooth-like optical properties namely color and translucency and maintain them for a long time. This study aimed to compare the effect of accelerated artificial aging (AAA) on the translucency of three methacrylate-based composites (Filtek Z250, Filtek Z250XT and Filtek Z350XT) and one silorane-based composite resin (Filtek P90).
  
  
  METHODS
  For this in vitro study, 56 composite discs were fabricated (n=14 for each group). Using scanning spectrophotometer, CIE L*a*b* parameters and translucency of each specimen were measured at 24 hours and after AAA for 384 hours. Data were analyzed using one-way ANOVA, Tukey's test and paired t-test at P=0.05 level of significance.
  
  
  RESULTS
  The mean (±standard deviation) translucency parameter for Filtek Z250, Filtek Z250XT, Filtek Z350XT and Filtek P90 was 5.67±0.64, 4.59±0.77, 7.87±0.82 and 4.21±0.71 before AAA and 4.25±0.615, 3.53±0.73, 5.94±0.57 and 4.12±0.54 after AAA, respectively. After aging, the translucency of methacrylate-based composites decreased significantly (P<0.05). However, the translucency of Filtek P90 did not change significantly (P>0.05).
  
  
  CONCLUSIONS
  The AAA significantly decreased the translucency of methacrylate-based composites (Filtek Z250, Filtek Z250XT and Filtek Z350XT) but no change occurred in the translucency of Filtek P90 silorane-based composite.
authors.affiliation: Associate Professor, Department of Operative Dentistry, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Shirinzad
authors.affiliation: Associate Professor, Dental Research Center, Department of Operative Dentistry, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Loghman
authors.initials: L
authors.lastname: Rezaei-Soufi
authors.affiliation: Specialist in Operative Dentistry, Gorgan, Iran.
authors.forename: Maryam Sadat
authors.initials: MS
authors.lastname: Mirtorabi
authors.affiliation: Dentist, Hamadan, Iran.
authors.forename: Farshid
authors.initials: F
authors.lastname: Vahdatinia
keywords: Composite Resins; Methacrylates; Silorane Resins