title: Effect of light energy density on conversion degree and hardness of dual-cured resin cement.
abstract: This study evaluated the effect of different light energy densities on conversion degree (CD) and Knoop hardness number (KHN) of RelyX ARC (RLX) resin cement. After manipulation according to the manufacturer's instructions, RLX was inserted into a rubber mold (0.8 mm x 5 mm) and covered with a Mylar strip. The tip of the light-curing unit (LCU) was positioned in contact with the Mylar surface. Quartz-tungsten-halogen (QTH) and light-emitting diode (LED) LCUs with light densities of 10, 20 and 30 J/cm2 were used to light-cure the specimens. After light curing, the specimens were stored dry in lightproof containers at 37 degrees C. After 24 hours, the CD was analyzed by FT-Raman and, after an additional 24-hours, samples were submitted to Knoop hardness testing. The data of the CD (%) and KHN were submitted to two-way ANOVA and the Tukey's test (alpha = 0.05). QTH and LED were effective light curing units. For QTH, there were no differences among the light energy densities for CD or KHN. For LED, there was a significant reduction in CD with the light energy density set at 10 J/cm2. KHN was not influenced by the light-curing unit and by its light energy density.
authors.affiliation: Dental Materials and Prosthodontics Department, Sao Jose dos Campos Dental School-UNESP, Sao Jose dos Campos, SP, Brazil. komori@fosjc.unesp.br
authors.forename: Paula Carolina de Paiva
authors.initials: PC
authors.lastname: Komori
authors.forename: Andréia Bolzan
authors.initials: AB
authors.lastname: de Paula
authors.forename: Airton Abrāo
authors.initials: AA
authors.lastname: Martin
authors.forename: Rubens Nisie
authors.initials: RN
authors.lastname: Tango
authors.forename: Mario Alexandre Coelho
authors.initials: MA
authors.lastname: Sinhoreti
authors.forename: Lourenço
authors.initials: L
authors.lastname: Correr-Sobrinho
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry* / Q000528:radiation effects; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D055117:Curing Lights, Dental / Q000145:classification; D006244:Hardness; D006801:Humans; D008027:Light; D008422:Materials Testing; D055668:Photochemical Processes; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000528:radiation effects; D011108:Polymers / Q000737:chemistry / Q000528:radiation effects; D011109:Polymethacrylic Acids / Q000737:chemistry* / Q000528:radiation effects; D011829:Radiation Dosage; D019279:Resin Cements / Q000737:chemistry* / Q000528:radiation effects; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D013997:Time Factors
chemical_list: D003188:Composite Resins; D011108:Polymers; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate