title: Color stability and degree of cure of direct composite restoratives after accelerated aging.
abstract: OBJECTIVE
  This study evaluated the color changes and amount of remaining C = C bonds (%RDB) in three dental composites after hydrothermal- and photoaging.
  
  
  METHODS
  The materials tested were Estelite sigma, Filtek Supreme and Tetric Ceram. Specimens were fabricated from each material and subjected to L* a* b* colorimetry and FTIR spectroscopy before and after aging. Statistical evaluation of the deltaL,* deltaa,* deltab,* deltaE and %deltaRDB data was performed by one-way ANOVA and Tukey's test. The %RDB data before and after aging were statistically analyzed using two-way ANOVA and Student-Newman-Keuls test. In all cases an alpha = 0.05 significance level was used.
  
  
  RESULTS
  No statistically significant differences were found in deltaL*, deltaa*, deltaE and %deltaRDB among the materials tested. Tetric Ceram demonstrated a significant difference in deltab*. All the materials showed visually perceptible (deltaE >1) but clinically acceptable values (deltaE < 3.3). Within each material group, statistically significant differences in %RDB were noticed before and after aging (p < 0.05). Filtek Supreme presented the lowest %RDB before aging, with Tetric Ceram presenting the lowest %RDB after aging (p < 0.05). The %deltaRDB mean values were statistically significantly different among all the groups tested. No correlation was found between deltaE and %deltaRDB.
authors: Department of Prosthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
authors: Aspasia
authors: A
authors: Sarafianou
authors: Soultana
authors: S
authors: Iosifidou
authors: Triantafillos
authors: T
authors: Papadopoulos
authors: George
authors: G
authors: Eliades
mesh_terms: D000704:Analysis of Variance; D003116:Color; D003124:Colorimetry; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D003793:Dental Restoration, Permanent / Q000379:methods; D003799:Dental Stress Analysis; D006244:Hardness; D008027:Light; D008422:Materials Testing; D015394:Molecular Structure; D044367:Phase Transition; D017550:Spectroscopy, Fourier Transform Infrared; D018709:Statistics, Nonparametric; D013997:Time Factors
chemical_list: D003188:Composite Resins; C507124:Estelite sigma; C474035:Filtek Supreme; C121818:Tetric ceram