EFFECT OF FIBER DIRECTION ON THE POLYMERIZATION SHRINKAGE OF FIBER-REINFORCED COMPOSITES

Abstract

The aim of this study was to evaluate the effect of fiber direc tion on the polymerization shrinkage of fiber-reinforced composite. The disc-shaped flowable composite specimens (d = 10 mm, h = 2 mm, Aeliteflo A2,Bisco, Inc., IL, USA) with or without glass fiber bundle (X-80821P Glass Fiber, Bisco, Inc., IL, USA)inside were prepared, and the longitudinal and transversal polymerization shrinkage of the specimens onradial plane were measured with strain gages (Linear S-series 350Ω, CAS, Seoul, Korea). In order to mea-sure the free polymerization shrinkage of the flowable composite itself, the disc-shaped specimens (d = 7mm, h = 1 mm) without fiber were prepared, and the axial shrink age was measured with an LVDT (linearvariable differential transformer) displacement sensor. The cross-section of the polymerized specimens wasobserved with a scanning electron microscope to examine the arrangement of the fiber bundle in composite.The mean polymerization shrinkage value of each specimen group was analyzed with ANOVA and Scheffepost-hoc test (α=0.05).The radial polymerization shrinkage of fiber-reinforced composite was decreased in the longitudinal direc-tion of fiber, but increased in the transversal direction of fiber (p<0.05). We can conclude that the polymer-ization shrinkage of fiber-reinforced composite splint or restoratives is dependent on the direction of fiber.[J Kor Acad Cons Dent 34(4):364-370, 2009]Key words:fiber-reinforced composite, longitudinal direction, transversal direction, polymerization shrinkage, strain gage, linear variable differential transformer-Received 2009.5.11., revised 2009.5.31., accepted 2009.6.25.-