title: Impact strength of denture base and reline acrylic resins subjected to long-term water immersion.
abstract: Water may influence the mechanical properties of the acrylic resins. Thus, the effect of water storage on the impact strength (IS) of one denture base (Lucitone 550 - L) and four reline resins (Tokuyama Rebase II - T; UfiGel Hard - U; Kooliner - K; New Truliner - NT) was evaluated. Bars of L were made (60 x 6 x 2 mm) and relined (2 mm) with T, U, K, NT and L. Intact specimens of each material (60 x 6 x 4 mm) were also fabricated for comparative purposes. Specimens were submitted to Charpy impact tests without water storage (control) and after immersion in water for 7, 90 and 180 days. Data (kJ/m(2)) analyzed by two-way ANOVA and Tukey's test (p=0.05) revealed that after 90 days, U exhibited an increase in the IS (0.93) compared to 7 days (0.58). K (1.48) and L/K (7.21) exhibited a decrease at the 7-day period (1.01 and 3.23, respectively). NT (0.60) showed an increase in the IS after 180 days (1.52), whereas L/NT (7.70) showed a decrease (3.17). Water immersion improved the IS of U and NT, and decreased the IS of K, L/K, and L/NT. Water may affect differently the IS of acrylic resins and, consequently, the resistance to fracture of relined denture bases.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, Univ. Estadual Paulista, SP, Brazil.
authors.forename: Amanda Fucci
authors.initials: AF
authors.lastname: Wady
authors.forename: Ana Lucia
authors.initials: AL
authors.lastname: Machado
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Vergani
authors.forename: Ana Cláudia
authors.initials: AC
authors.lastname: Pavarina
authors.forename: Eunice Teresinha
authors.initials: ET
authors.lastname: Giampaolo
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000268:Adhesiveness; D001732:Bite Force; D003799:Dental Stress Analysis; D003819:Denture Bases; D003822:Denture Liners; D003823:Denture Rebasing; D007101:Immersion; D008422:Materials Testing; D014867:Water
chemical_list: D000180:Acrylic Resins; D014867:Water