title: Analysis of the microstructure and mechanical performance of composite resins after accelerated artificial aging.
abstract: OBJECTIVE
  Researches that assess the behavior of dental materials are important for scientific and industrial development especially when they are tested under conditions that simulate the oral environment, so this work analyzed the compressive strength and microstructure of three composite resins subjected to accelerated artificial aging (AAA).
  
  
  METHODS
  Three composites resins of 3M (P90, P60 and Z100) were analyzed and were obtained 16 specimens for each type (N.=48). Half of each type were subjected to UV-C system AAA and then were analyzed the surfaces of three aged specimens and three not aged of each type through the scanning electron microscope (SEM). After, eight specimens of each resin, aged and not aged, were subjected to compression test.
  
  
  RESULTS
  After statistical analysis of compressive strength values, it was found that there was difference between groups (α <0.05). The resin specimens aged P60 presented lower values of compressive strength statistically significant when compared to the not subject to the AAA. For the other composite resins, there was no difference, regardless of aging, a fact confirmed by SEM.
  
  
  CONCLUSIONS
  The results showed that the AAA influenced the compressive strength of the resin aged P60; confirmed by surface analysis by SEM, which showed greater structural disarrangement on surface material.
authors.affiliation: School of Dentistry of Ribeirão Preto, FORP-USP, São Paulo, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: De Oliveira Daltoé
authors.forename: C Penazzo
authors.initials: CP
authors.lastname: Lepri
authors.forename: J Guilherme G
authors.initials: JG
authors.lastname: Wiezel
authors.forename: D Cremonezzi
authors.initials: DC
authors.lastname: Tornavoi
authors.forename: J A Marcondes
authors.initials: JA
authors.lastname: Agnelli
authors.forename: A Cândido Dos
authors.initials: AC
authors.lastname: Reis
mesh_terms: D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D019245:Compressive Strength; D003799:Dental Stress Analysis; D066298:In Vitro Techniques; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D012822:Silicon Dioxide / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays; D015040:Zirconium / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D003188:Composite Resins; C443708:P60 Condensible Resin Composite; C083568:Z100 composite resin; D012822:Silicon Dioxide; D015040:Zirconium