Short glass fiber reinforced restorative composite resin with semi-inter penetrating polymer network matrix

The purpose of this study was to investigate the reinforcing effect of short E-glass fiber fillers on some mechanical properties of dental composite resin with interpenetrating polymer network (IPN)-polymer matrix.

Experimental composite resin was prepared by mixing short fibers (3mm in length) with a fraction of 22.5 wt% and IPN-resin 22.5 wt% with silane treated silica filler 55 wt% using high speed mixing machine. Test specimens (2 mm x 2 mm x 25 mm) and (9.5 mm x 5.5 mm x 3 mm) were made from the experimental composite (FC) and conventional particulate composite resin (control, Z250, 3M-ESPE). The test specimens (n=6) were either dry stored or water stored (37 degrees C for 30 days) before the mechanical tests. Three-point bending test was carried out according to ISO 10477 and compression loading test was carried out using a steel ball (Ø3.0mm) with speed of 1.0mm/min until fracture. Degree of monomer conversion (DC%) of both composites was determined by FTIR spectrometry. Water sorption and solubility of specimens were also measured. Scanning electron microscopy was used to evaluate the microstructure of the composite.

ANOVA revealed that experimental fiber composite had statistically significantly higher mechanical performance of flexural strength (210 MPa) and compressive load-bearing capacity (1881 N) (p < 0.05) than control composite (111 MPa, 1031 N). Degree of conversion of the FC (59%) and conventional composite (57%) was at the same range.

The use of short fiber fillers with IPN-polymer matrix yielded improved mechanical performance compared to conventional restorative composite.