Abstract: Objective To study the effect of pretension of glass fiber on mechanical properties of newly developed glass fiber reinforced lightcured resin composite(FRC) posts.Methods Glass fibers were stretched 0,0.5% and 0.1% respectively.The glass fibers without pretension were used to be the control group.Each kind of glass fibers were mixed into the resin matrix respectively with a 60%,and then were lightcured within a special transparent mold to prepare the FRC specimens.FRC specimens were subjected to a threepoint flexural bending test to establish the flexural module,the flexural strength and fracture loads.Data were analyzed using a oneway analysis of variance and the Tukey HSD post hoc tests (α=0 .05).A field emission scanning electron microscope was used to observe the cross section surface of FRC and the fracture surface of the FRC after threepoint flexural bending test.Results Different pretension rates of glass fibers imposed different effects on mechanical properties of FRC posts.FRC posts with 1% pretension rate presented flexure modulus of (20.40±1.40) GPa,flexure strength of (573.38±29.45) MPa,and flexure load of (180.42±5.88) N,which were statistically higher than the FRC posts reinforced with glass fibers subjected to no pretension (P<0.05).Conclusions Glass fiber pretension can be used to reinforce FRC.

Key words: pretension, glass fiber, lightcured resin, mechanical property