title: Evaluation of phenyl-propanedione on yellowing and chemical-mechanical properties of experimental dental resin-based materials.
abstract: OBJECTIVE
  To evaluate the influence of phenyl-propanedione on yellowing and chemical-mechanical properties of experimental resin-based materials photoactivated using different light curing units (LCUs).
  
  
  METHODS
  Experimental resin-based materials with the same organic matrix (60:40 wt% BisGMA:TEGDMA) were mechanically blended using a centrifugal mixing device. To this blend, different photoinitiator systems were added in equimolar concentrations with aliphatic amine doubled by wt%: 0.4 wt% CQ; 0.38 wt% PPD; or 0.2 wt% CQ and 0.19 wt% PPD. The degree of conversion (DC), flexural strength (FS), Young's modulus (YM), Knoop hardness (KNH), crosslinking density (CLD), and yellowing (Y) were evaluated (n=10). All samples were light cured with the following LCUs: a halogen lamp (XL 2500), a monowave LED (Radii), or a polywave LED (Valo) with 16 J/cm2. The results were analysed by two-way ANOVA and Tukey's test (α=0.05).
  
  
  RESULTS
  No statistical differences were found between the different photoinitiator systems to KNH, CLS, FS, and YM properties (p≥0.05). PPD/CQ association showed the higher DC values compared with CQ and PPD isolated systems when photoactivated by a polywave LED (p≤0.05). Y values were highest for the CQ compared with the PPD systems (p≤0.05).
  
  
  CONCLUSIONS
  PPD isolated system promoted similar chemical and mechanical properties and less yellowing compared with the CQ isolated system, regardless of the LCU used.
authors.affiliation: - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba, Departamento de Odontologia Restauradora, Piracicaba, SP, Brasil.
authors.forename: Dayane Carvalho Ramos Salles de
authors.initials: DC
authors.lastname: Oliveira
authors.affiliation: - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba, Departamento de Odontologia Restauradora, Piracicaba, SP, Brasil.
authors.forename: Eduardo José
authors.initials: EJ
authors.lastname: Souza-Junior
authors.affiliation: - Oregon Health & Science University, Department of Biomaterials, Portland, Oregon, United States of America.
authors.forename: Adam
authors.initials: A
authors.lastname: Dobson
authors.affiliation: - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba, Departamento de Odontologia Restauradora, Piracicaba, SP, Brasil.
authors.forename: Ana Rosa Costa
authors.initials: AR
authors.lastname: Correr
authors.affiliation: - Universidade de Santo Amaro, Departamento de Implantodontia, São Paulo, SP, Brasil.
authors.forename: William Cunha
authors.initials: WC
authors.lastname: Brandt
authors.affiliation: - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba, Departamento de Odontologia Restauradora, Piracicaba, SP, Brasil.
authors.forename: Mário Alexandre Coelho
authors.initials: MA
authors.lastname: Sinhoreti
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D002164:Camphor / Q000031:analogs & derivatives / Q000737:chemistry; D047188:Chalcones / Q000737:chemistry*; D003116:Color; D055117:Curing Lights, Dental; D055119:Elastic Modulus; D006245:Hardness Tests; D055115:Light-Curing of Dental Adhesives / Q000379:methods*; D008422:Materials Testing; D044367:Phase Transition; D058567:Photoinitiators, Dental / Q000737:chemistry*; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry*; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry*; D017797:Prosthesis Coloring; D015203:Reproducibility of Results; D013053:Spectrophotometry; D017550:Spectroscopy, Fourier Transform Infrared; D018709:Statistics, Nonparametric
chemical_list: D047188:Chalcones; D058567:Photoinitiators, Dental; D011109:Polymethacrylic Acids; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D002164:Camphor; C553149:camphorquinone; C100349:1-phenyl-1,2-propanedione