SIGNIFICANCE This study did not identify clear advantages of using the first generation of ormocer-based fillings rather than conventional composites .
OBJECTIVES In-vitro experiments on  ormocers ( ORganically MOdified CERamics )  have provided controversial results .
Consequently , the objectives of this meta- analysis were to ( 1 ) compare clinical performances of first generation ormocers versus conventional composite restorations  , ( 2 ) explore the influence of various clinical factors and the impact of the quality of studies on published results .
Monomer elution from nanohybrid and ormocer-based composites cured with different light sources.
OBJECTIVES To study monomer elution from four resin-based composites ( RBCs )  cured with different light sources . METHODS Twenty-eight premolars were r and omly allocated to four groups . St and ardized cavities were prepared and restored with a nanohybrid ( Filtek Supreme XT or Tetric EvoCeram ) , an ormocer ( Admira ) or a microhybrid RBC ( Filtek Z250 ) which served as control . Buccal restorations were cured with a halogen and oral restorations with an LED light-curing unit . Elution of diurethane dimethacrylate ( UDMA ) , Bisphenol A diglycidylether methacrylate ( BisGMA ) , triethylene glycol dimethacrylate ( TEGDMA ) and 2-hydroxyethyl methacrylate ( HEMA ) was analyzed using high-performance liquid chromatography ( HPLC ) 1h to 28 days post-immersion in 75 % ethanol . Data were analyzed using multivariate and repeated measures analysis of variance ( α = 0.05 ) . RESULTS The greatest elution of UDMA and BisGMA occurred from Tetric EvoCeram and the least from Filtek Z250 ( p < 0.05 ) . LED and halogen light-curing units gave similar results for all RBCs ( p > 0.05 ) except Tetric EvoCeram which showed greater elution for the LED unit ( p < 0.05 ) . TEGDMA was below the limit of quantification . HEMA eluted in similar concentrations from Filtek Supreme and Tetric EvoCeram ( p > 0.05 ) . SIGNIFICANCE The two nanohybrid RBCs eluted more cross-linking monomers than the ormocer and the control microhybrid RBC . Continuous elution over 28 days indicates that RBCs act as a chronic source of monomers in clinical conditions . Light source may affect monomer elution since differences were found for one out of four RBCs . Mathematical models for elution kinetics of UDMA and BisGMA indicated two elution mechanisms
SIGNIFICANCE This study did not identify clear advantages of using the first generation of ormocer-based fillings rather than conventional composites .
OBJECTIVES In-vitro experiments on  ormocers ( ORganically MOdified CERamics )  have provided controversial results .
Consequently , the objectives of this meta- analysis were to ( 1 ) compare clinical performances of first generation ormocers versus conventional composite restorations  , ( 2 ) explore the influence of various clinical factors and the impact of the quality of studies on published results .