title: Contraction stress, elastic modulus, and degree of conversion of three flowable composites.
abstract: The aim of this study was to measure the contraction stress of three flowable resin composites and to correlate the stress with the elastic modulus and the degree of conversion. One low-shrinkage (Venus Diamond Flow) and two conventional (Tetric EvoFlow and X-Flow) flowable composites were polymerized for 40s with a light-emitting diode (LED) curing unit. Contraction force was continuously recorded for 300s using a stress-analyser, and stress values were calculated at 40s and at 300s. The maximum stress rate was also calculated for each specimen. The elastic modulus of each composite was assayed using a biaxial flexural test, and degree of conversion was analysed with Raman spectroscopy. X-Flow exhibited higher stress values than the other tested materials. Venus Diamond Flow showed the lowest stress values at 40s and at 300s, and the lowest maximum stress rate. Stress values were correlated with elastic modulus but not with degree of conversion, which was comparable among all tested materials.
authors.affiliation: Department of Biomedicine, Unit of Dental Sciences and Biomaterials, University of Trieste, Trieste, Italy. m.cadenaro@fmc.units.it
authors.forename: Milena
authors.initials: M
authors.lastname: Cadenaro
authors.forename: Barbara
authors.initials: B
authors.lastname: Codan
authors.forename: Chiara O
authors.initials: CO
authors.lastname: Navarra
authors.forename: Giulio
authors.initials: G
authors.lastname: Marchesi
authors.forename: Gianluca
authors.initials: G
authors.lastname: Turco
authors.forename: Roberto
authors.initials: R
authors.lastname: Di Lenarda
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Breschi
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003799:Dental Stress Analysis; D055119:Elastic Modulus; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D018583:Pliability; D013314:Stress, Mechanical; D014783:Viscosity
chemical_list: D003188:Composite Resins