Mechanical behavior and adhesive potential of glass fiber-reinforced resin-based composites for use as dentin analogues.

Purpose: To characterize experimental glass fiber-reinforced resin-based composites (GFIR-isophthalic; and GFOR-orthophthalic), evaluating their mechanical behavior and adhesive potential to ceramic in comparison to human dentin and a traditional glass fiber-reinforced epoxy resin (G10).

Methods: Density (ρ), elastic modulus (E), and Poisson's ratio (ν) were evaluated using 2 mm thick specimens from GFIR, GFOR, human dentin and G10. Biaxial flexural strength (δf), Knoop hardness and surface topography under scanning electron microscopy (SEM) were assessed for GFIR and GFOR specimens. G10 was also tested for δf. For the adhesive potential, ceramic specimens (n=10) bonded to GFIR, GFOR or human dentin were tested for microtensile bond strength (MTBS). Disc-shaped ceramics were cemented onto dentin, GFIR, GFOR and G10 (n=15) and loaded to failure. Data were statistically evaluated using Weibull, ANOVA, and Tukey's test (α=0.05).

Results: The experimental resins (GFIR and GFOR) showed similar values of HK (53.1 and 52.7 GPa), (ν (0.44 and 0.43) and δf (41.2 MPa and 40.7 MPa). Considering the human dentin values for ρ and E, the corresponding values obtained from GFIR, GFOR and G10 were different, with GFOR values being closer to dentin than GFIR and G10. G10 had statistically greater(δf than GFIR and GFOR. Mean bond strength of ceramic to GFIR, GFOR and dentin were statistically similar. The fracture load of resin-cemented ceramic was influenced by substrate.

Clinical Significance: The experimental materials (GFIR and GFOR) showed similar adhesion characteristics to human dentin, however GFOR showed a better potential to be used as a dentin analogue.