title: Changes in surface roughness and color stability of two composites caused by different bleaching agents.
abstract: The objective of this study was to evaluate the effect of two bleaching agents (10% and 35% hydrogen peroxide) on the color stability and surface roughness of two composites, one nanohybrid and one nanoparticle. Specimens were polished, aged, stained, bleached and polished again. The action of the bleaching agents on the composites was analyzed using a profilometer (surface roughness) and a spectrophotometer (color stability). The effect of polishing the composites on the surface roughness and the resumption of the composite color was also evaluated. The results were analyzed statistically by ANOVA and Tukey's test at 5% significance level. The analysis indicated that the nanohybrid composite was more affected by staining. The bleaching agents were not able to promote bleaching of either composite over the evaluation period. Surface polishing returned nanohybrid composite to its original color condition, which did not occur for the nanoparticle composite. Additionally, polishing did not return the surface roughness of either composite to its original value. It may be concluded that polishing surface after bleaching should not be the treatment of choice, as it was not possible to reverse the roughness of the composites to their original values, suggesting that a more extensive and irreversible degradation might have occurred.
authors: Department of Dentistry, Dental School, UERJ - State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors: Anna Paula Kalix França
authors: AP
authors: Mendes
authors: Marcos de Oliveira
authors: Mde O
authors: Barceleiro
authors: Rodrigo Sant'Anna Aguiar
authors: RS
authors: dos Reis
authors: Lucilei Lopes
authors: LL
authors: Bonato
authors: Kátia Regina Hostílio Cervantes
authors: KR
authors: Dias
mesh_terms: D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D003069:Coffee / Q000737:chemistry; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing / Q000295:instrumentation / Q000379:methods; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry*; D008027:Light; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry; D012464:Saliva, Artificial / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D013053:Spectrophotometry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D058205:Tooth Bleaching Agents / Q000737:chemistry*
chemical_list: D017554:Carbon Compounds, Inorganic; D003069:Coffee; D003188:Composite Resins; D003764:Dental Materials; D012464:Saliva, Artificial; D017655:Silicon Compounds; C113300:TPH hybrid; D058205:Tooth Bleaching Agents; C533204:filtek Z350; D006861:Hydrogen Peroxide; C022088:silicon carbide