title: Color stability of repaired composite submitted to accelerated artificial aging.
abstract: The aim of this study was to evaluate the color stability (ΔE) of nanoparticulate composite, with consideration for the type of surface treatment performed before repair. A Teflon matrix was used to fabricate 50 test specimens from composite. After initial color readout, the specimens were submitted to 100 hours of accelerated artificial aging (AAA). The samples were divided into five groups (n = 10), according to the surface treatment performed: sandblasting with aluminum oxide powder, phosphoric acid, and an adhesive system (Group 1); sandblasting with aluminum oxide powder, phosphoric acid, and a flowable composite (Group 2); abrasion with a diamond bur, phosphoric acid, and an adhesive system (Group 3); abrasion with a diamond bur, phosphoric acid, and a nanoparticulate composite (Group 4); and a control group (Group 5).  After repair, a new color readout was taken, the test specimens were submitted to a new AAA cycle (300 hours), and the final color readout was taken. Comparison of the ΔE means (one-way ANOVA and Tukey tests, p < 0.05) demonstrated no statistically significant differences among the groups (p > 0.05) after 100 hours of AAA. After repair, Group 1 (4.61 ± 2.03) presented the highest color alteration with a statistically significant difference compared with the other groups (p < 0.05). After 300 hours, Group 4 specimens (13.84 ± 0.71) presented the lowest color alteration in comparison with the other groups, with a statistically significant difference (p < 0.05). It was concluded that the repair performed in Group 4 provided greater esthetic recovery, made possible by the regression in the ΔE values of the restorations after repair, and less color alteration of the restorations over the course of time.
authors.affiliation: Ribeirao Preto School of Dentistry, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil.
authors.forename: Ana Beatriz Silva
authors.initials: AB
authors.lastname: Souza
authors.forename: Francisca Daniele Jardilino
authors.initials: FD
authors.lastname: Silame
authors.forename: Carla Cecilia
authors.initials: CC
authors.lastname: Alandia-Roman
authors.forename: Diogo Rodrigues
authors.initials: DR
authors.lastname: Cruvinel
authors.forename: Lucas da Fonseca Roberti
authors.initials: Lda F
authors.lastname: Garcia
authors.forename: Fernanda de Carvalho Panzeri
authors.initials: Fde C
authors.lastname: Pires-de-Souza
mesh_terms: D000704:Analysis of Variance; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D058250:Dental Restoration Repair / Q000379:methods*; D008422:Materials Testing / Q000379:methods; D049329:Nanostructures / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D003188:Composite Resins; C111840:flowable hybrid composite