title: Influence of delivered radiant exposure values on bonding of fiber posts to root canals.
abstract: OBJECTIVE
  To evaluate the effect of different radiant exposure values delivered to two simplified etch-and-rinse adhesive systems on push-out bond strength (PBS) of fiber posts to root canal, as well as nanoleakage (NL) and in situ degree of conversion (DC) within the hybrid layer.
  
  
  METHODS
  The roots of human premolars were endodontically prepared and divided into 6 groups according to the combination of the main factors adhesive/resin cement (2 commercial brands) and radiant exposure (4, 16, 48, and 288 J/cm2). The posts were cemented and the PBS tested at 0.5 mm/min (n = 7). The NL (n = 3) was evaluated using SEM after immersion of specimens in 50% silver nitrate. Micro-Raman spectroscopy was performed to determine the in situ DC (n = 2). Data were analyzed by three-way repeated measures ANOVA and Tukey's post-hoc test (5%).
  
  
  RESULTS
  PBS (MPa) showed a significant difference only for the middle third when an increase in radiant exposure from 4 to 16 J/cm2 or higher was used (p < 0.05). The NL (%) decreased significantly with increasing radiant exposure from 48 to 288 J/cm2 in the middle and apical thirds when compared to lower radiant exposure (p < 0.05). The radiant exposure of 288 J/cm2 significantly increased the DC (%) in the middle and apical thirds, compared the other radiant exposure values (p < 0.05).
  
  
  CONCLUSIONS
  The increase in radiant exposure delivered to the cervical third of root canals during post cementation improved the adhesive performance of simplified etch-and-rinse adhesive systems in the apical and middle thirds.
authors.forename: Anna
authors.initials: A
authors.lastname: Szesz
authors.forename: Johanna
authors.initials: J
authors.lastname: Cuadros-Sánchez
authors.forename: Viviane
authors.initials: V
authors.lastname: Hass
authors.forename: Gerson Kniphoff
authors.initials: GK
authors.lastname: da Cruz
authors.forename: Cesar A G
authors.initials: CA
authors.lastname: Arrais
authors.forename: Alessandra
authors.initials: A
authors.lastname: Reis
authors.forename: Alessandro Dourado
authors.initials: AD
authors.lastname: Loguercio
mesh_terms: D001641:Bicuspid / Q000648:ultrastructure; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002484:Cementation / Q000379:methods; D003763:Dental Leakage / Q000145:classification; D003786:Dental Pulp Cavity / Q000648:ultrastructure*; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000379:methods*; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation*; D011829:Radiation Dosage; D019279:Resin Cements / Q000737:chemistry / Q000528:radiation effects*; D016622:Silver Staining; D013059:Spectrum Analysis, Raman; D013314:Stress, Mechanical; D013499:Surface Properties; D019227:Tooth Apex / Q000648:ultrastructure
chemical_list: C420130:Excite cement; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; D019279:Resin Cements; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; C103502:Variolink; C041979:2,2-bis-(4-(2-methacryloxyethoxy)phenyl)propane; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate