title: Flexural and diametral tensile strength of composite resins.
abstract: This study evaluated the flexural strength (sf) and the diametral tensile strength (st) of light-cured composite resins, testing the hypothesis that there is a positive relation between these properties. Twenty specimens were fabricated for each material (Filtek Z250- 3M-Espe; AM- Amelogen, Ultradent; VE- Vit-l-escence, Ultradent; EX- Esthet-X, Dentsply/Caulk), following ISO 4049 and ANSI/ADA 27 specifications and the manufacturers instructions. For the st test, cylindrical shaped (4 mm x 6 mm) specimens (n = 10) were placed with their long axes perpendicular to the applied compressive load at a crosshead speed of 1.0 mm/min. The sf was measured using the 3-point bending test, in which bar shaped specimens (n = 10) were tested at a crosshead speed of 0.5 mm/min. Both tests were performed in a universal testing machine (EMIC 2000) recording the fracture load (N). Strength values (MPa) were calculated and statistically analyzed by ANOVA and Tukey (a = 0.05). The mean and standard deviation values (MPa) were Z250-45.06 +/- 5.7; AM-35.61 +/- 5.4; VE-34.45 +/- 7.8; and EX-42.87 +/- 6.6 for st; and Z250-126.52 +/- 3.3; AM-87.75 +/- 3.8; VE-104.66 +/- 4.4; and EX-119.48 +/- 2.1 for sf. EX and Z250 showed higher st and sf values than the other materials evaluated (p < 0.05), which followed a decreasing trend of mean values. The results confirmed the study hypothesis, showing a positive relation between the material properties examined.
authors.affiliation: School of Dentistry, University of Passo Fundo, Passo Fundo, RS, Brazil.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Della Bona
authors.forename: Paula
authors.initials: P
authors.lastname: Benetti
authors.forename: Márcia
authors.initials: M
authors.lastname: Borba
authors.forename: Dileta
authors.initials: D
authors.lastname: Cecchetti
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods / Q000592:standards; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000379:methods* / Q000592:standards; D003799:Dental Stress Analysis; D008027:Light; D008422:Materials Testing / Q000379:methods; D013718:Tensile Strength
chemical_list: D003188:Composite Resins; D003764:Dental Materials