• Prapaporn Homjunjeerung D.D.S. (Hons)
• Issarawan Boonsiri D.D.S., Cert. in Fixed Prosth

Objective To determine the effects of two different coupling agents and storage times on transverse
strength of acrylic resin with glass fiber reinforcement.

Materials and methods Eighty test specimens (2x2x25 mm) made of chemically activated acrylic
resin were divided into four groups: (A) no fibers; (B) non-impregnated glass fibers; (C) silane
impregnated glass fibers and (D) titanate impregnated glass fibers. The specimens in group B-D were
reinforced with 10% volume of glass fibers which were oriented parallel to the long axis and positioned
in the center of the specimen. Each group was subdivided to store in distilled water for 7 and 30 days
at 37 °C before testing. They were subjected to a three-point loading test set up at a crosshead speed of
1 mm/min. Scanning electron microscopy was used to examine the microstructure of the cracked
surface. Transverse strengths were analyzed by means of Two-way ANOVA.

Results There were statistically significant differences among the groups (p < 0.05). Transverse strength
of silane impregnated glass fiber group was higher than those of titanate impregnated glass fiber group,
non-impregnated glass fiber and no fiber group, respectively. The transverse strengths of each group
were decreased significantly from 7 days to 30 days of water storage (p < 0.05).

Conclusion Treating the surface of glass fibers with coupling agents produced significant improvement
in the transverse strength. The storage times had a significant effect on the transverse strength of
acrylic resin with glass fiber reinforcement.

(CU Dent J. 2008;31:349-58)