Light cure composite resin , Filler , Setting time , Polymerization shrinkage , Flow , Shrinkage stress The variation of polymerization shrinkage stress with time for 26 experimental composite resins applied on one surface of a thin glass beam has been determined. In addition , the amount of polymerization shrinkage of these materials during setting was investigated using a small glass ceH and an electric strain transducer ( UL − 50) . From these results , the effects of filler shape , filler

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... rticle size and filler content on shrinkage stress during setting were discussed . The increase of filler content in the material enlarged the deflection ( shrinkage stress )of the glass beam and reduced the amount of linear shrinkage during setting . Furthermore, this shrinkage stress also decreased with the use of a larger filler in an average particle size . In cases using the same filler content materials , the effects of filler shape ( irregular or spherical f三 11er )on shrinkage stress was not recognized in this experi 皿 ent .