title: Effect of thermal cycling on denture base and autopolymerizing reline resins.
abstract: OBJECTIVE
  This study evaluated the fracture toughness (FT) of denture base and autopolymerizing reline resins, with and without thermocycling (T).
  
  
  METHODS
  Specimens of each material (denture base acrylic resin - Lucitone 550 - L; autopolymerizing reline resins - Ufi Gel Hard-UH, Tokuyama Rebase II-TR, New Truliner-NT and Kooliner-K), were produced, notched and divided into two groups (n=10): CG (control group of autopolymerizing reline resins and L): FT tests were performed after polymerization; TG (thermocycled group): FT tests were performed after T (5°C and 55°C for 5,000 cycles).
  
  
  RESULTS
  Results (MPa.m1/2) were analyzed by two-way ANOVA and Tukey's test (p=0.05). L exhibited the highest FT mean values in both groups (CG - 2.33; TG - 2.17). For the CG groups, NT showed the highest FT (1.64) among the autopolymerizing reline resins, and K the lowest (1.04). After T, when the autopolymerizing reline resins were compared, a statistically significant difference in FT was found only between the NT (1.46) and TR (1.00).
  
  
  CONCLUSIONS
  Thermocycling increased the FT of K and did not influence the FT of L, UH, TR and NT.
authors.affiliation: Department of Dental Materials and Prosthodontics, School of Dentistry Araraquara, Univ. Estadual Paulista, Araraquara, SP, Brazil.
authors.forename: Cíntia de Souza
authors.initials: Cde S
authors.lastname: Silva
authors.forename: Ana Lucia
authors.initials: AL
authors.lastname: Machado
authors.forename: Carolina de Andrade Lima
authors.initials: Cde A
authors.lastname: Chaves
authors.forename: Ana Cláudia
authors.initials: AC
authors.lastname: Pavarina
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Vergani
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D019232:Dental Restoration Failure; D003819:Denture Bases; D003823:Denture Rebasing; D006801:Humans; D008422:Materials Testing; D058105:Polymerization; D012826:Silicone Elastomers / Q000737:chemistry*; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D012826:Silicone Elastomers