Flexural strength of glass and polyethylene fiber combined with three different composites.
BACKGROUND
The flexure of the fiber- reinforced composites (FRC) which can be generally used instead of fixed metal- framework prostheses have been more advocated due to the enormous demands for the conservative and esthetic restoration. The flexure of the fiber should be well-fitted to its covering composite. No study has been reported the comparison of the combination of glass and polyethylene fiber with particulate filled composite and fiber reinforced composite yet.


OBJECTIVE
This study compared the flexural strength of two types of fibers combined with three types of composites.


METHODS
Sixty-six specimens were prepared in a split mold (25×2×2 mm). The specimens were divided into six groups according to the type of resin and the fiber (N = 11): group 1: Z250 composite + Polyethylene fiber; group 2: Build It composite + Polyethylene fiber; group 3: Nulite F composite+ Polyethylene fiber; group 4: glass fiber + Z250 composite; group 5: glass fiber + Build-It composite and group 6: glass fiber + Nulite F. The mean ﬂexural strengths (MPa) values were determined in a 3-point bending test at a crosshead speed of 1 mm/min by a universal testing machine (Zwick/Roell Z020, Germany). The results were statistically analyzed, using one and two- way ANOVA and LSD post-hoc tests (p< 0.05).


RESULTS
The highest flexural strength was registered for glass fiber in combination with Z250 composite (500 MPa) and the lowest for polyethylene fiber in combination with Build-It composite (188 MPa). One-way ANOVA test revealed that there was no statistically significant difference between polyethylene fiber combinations (p= 0.62) but there was a significant difference between glass fiber combinations (p= 0.0001). Two-way ANOVA revealed that the fiber type had a significant effect on flexural strength (p= 0.0001).


CONCLUSIONS
The choice of ﬁber and composite type was shown to have a signiﬁcant positive influence on the ﬂexural properties of the ﬁber-reinforced composite. Glass fiber has a significant influence on the flexural properties of directly- made specimens.
Dept. of Operative Dentistry, Biomaterials Research Center, School of Dentistry, Shiraz University of Medial Sciences, Shiraz, Iran.
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F
Sharafeddin
Dept. of Operative Dentistry, Biomaterials Research Center, School of Dentistry, Shiraz University of Medial Sciences, Shiraz, Iran.
Aa
A
Alavi
Dept. of Operative Dentistry, School of Dentistry, Shiraz University of Medial Sciences, Shiraz, Iran.
Z
Z
Talei
Composite; Flexural Strength; Glass Fiber; Poly Ethylene Fiber