title: Influence of artificial accelerated aging on dimensional stability of acrylic resins submitted to different storage protocols.
abstract: OBJECTIVE
  The aim of this study was to evaluate the influence of artificial accelerated aging on dimensional stability of two types of acrylic resins (thermally and chemically activated) submitted to different protocols of storage.
  
  
  METHODS
  One hundred specimens were made using a Teflon matrix (1.5 cm x 0.5 mm) with four imprint marks, following the lost-wax casting method. The specimens were divided into ten groups, according to the type of acrylic resin, aging procedure, and storage protocol (30 days). GI: acrylic resins thermally activated, aging, storage in artificial saliva for 16 hours, distilled water for 8 hours; GII: thermal, aging, artificial saliva for 16 hours, dry for 8 hours; GIII: thermal, no aging, artificial saliva for 16 hours, distilled water for 8 hours, GIV: thermal, no aging, artificial saliva for 16 hours, dry for 8 hours; GV: acrylic resins chemically activated, aging, artificial saliva for 16 hours, distilled water for 8 hours; GVI: chemical, aging, artificial saliva for 16 hours, dry for 8 hours; GVII: chemical, no aging, artificial saliva for 16 hours, distilled water for 8 hours; GVIII: chemical, no aging, artificial saliva for 16 hours, dry for 8 hours GIX: thermal, dry for 24 hours; and GX: chemical, dry for 24 hours. All specimens were photographed before and after treatment, and the images were evaluated by software (UTHSCSA - Image Tool) that made distance measurements between the marks in the specimens (mm), calculating the dimensional stability. Data were submitted to statistical analysis (two-way ANOVA, Tukey test, p= 0.05).
  
  
  RESULTS
  Statistical analysis showed that the specimens submitted to storage in water presented the largest distance between both axes (major and minor), statistically different (p < 0.05) from control groups.
  
  
  CONCLUSIONS
  All acrylic resins presented dimensional changes, and the artificial accelerated aging and storage period influenced these alterations.
authors.affiliation: Department of Restorative Dentistry, Dental Materials Area, Piracicaba Dental School, Campinas State University, Piracicaba, Brazil.
authors.forename: Lucas da Fonseca Roberti
authors.initials: Lda F
authors.lastname: Garcia
authors.forename: Lourenço de Moraes Rego
authors.initials: Lde M
authors.lastname: Roselino
authors.forename: Fabrício Mariano
authors.initials: FM
authors.lastname: Mundim
authors.forename: Fernanda de Carvalho Panzeri
authors.initials: Fde C
authors.lastname: Pires-de-Souza
authors.forename: Simonides
authors.initials: S
authors.lastname: Consani
mesh_terms: D000042:Absorption; D000180:Acrylic Resins / Q000737:chemistry* / Q000528:radiation effects; D000327:Adsorption; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D003890:Desiccation; D004356:Drug Storage; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008422:Materials Testing; D010781:Photography; D012464:Saliva, Artificial / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; D012464:Saliva, Artificial; D014867:Water