title: Effect of accelerated aging on permanent deformation and tensile bond strength of autopolymerizing soft denture liners.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effect of different accelerated aging times on permanent deformation and tensile bond strength of two soft chairside liners, acrylic resin (T) and silicone (MS) based.
  
  
  METHODS
  Different specimens were made for each test of each reliner. The specimens (n = 10) were submitted to accelerated aging for 2, 4, 8, 16, 32, and 64 cycles. Tensile bond strength testing was performed at a crosshead speed of 5 mm/min and permanent deformation with a compressive load of 750 gf. Data were submitted to Mann-Whitney test to compare the materials at different times, and Kruskal-Wallis and Dunn tests were used for comparing aging intervals within a given reliner.
  
  
  RESULTS
  MS presented a lower percentage of permanent deformation (p < 0.0001) and higher tensile bond strength (p < 0.0001) than T in all time intervals and was not affected by the accelerated aging process, which reduced the permanent deformation and increased tensile bond strength of T (p < 0.05).
  
  
  CONCLUSIONS
  MS presented lower permanent deformation and higher tensile bond strength than T. Although T presented changes in those properties after accelerated aging, both materials might be suited for long-term use.
authors.affiliation: Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil. jemfkt@yahoo.com.br
authors.forename: Jessica Mie Ferreira Koyama
authors.initials: JM
authors.lastname: Takahashi
authors.forename: Rafael Leonardo Xediek
authors.initials: RL
authors.lastname: Consani
authors.forename: Guilherme Elias Pessanha
authors.initials: GE
authors.lastname: Henriques
authors.forename: Mauro Antônio de Arruda
authors.initials: MA
authors.lastname: Nóbilo
authors.forename: Marcelo Ferraz
authors.initials: MF
authors.lastname: Mesquita
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry* / Q000528:radiation effects; D000268:Adhesiveness; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D003799:Dental Stress Analysis / Q000295:instrumentation; D003822:Denture Liners; D006801:Humans; D008422:Materials Testing; D058105:Polymerization; D011145:Polyvinyls / Q000737:chemistry / Q000528:radiation effects; D012828:Silicones / Q000737:chemistry* / Q000528:radiation effects; D012833:Siloxanes / Q000737:chemistry / Q000528:radiation effects; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; D011145:Polyvinyls; C488492:QC 20 (denture base resin); D012828:Silicones; D012833:Siloxanes; C034183:vinyl polysiloxane; D014867:Water