Evaluation of physical properties of fiber-reinforced composite resin

Abstract

Objectives: This study aimed to investigate physical properties of a fiber-reinforced CAD/CAM resin disc, which included woven layers of multi-directional glass fibers.

Methods: Fiber orientations of CAD/CAM specimens (TRINIA, SHOFU) were specified as longitudinal (L), longitudinal-rotated (LR), and anti-longitudinal (AL). A fiber-reinforced composite (everX posterior, GC (E)) and a conventional composite (Beauti core flow paste, SHOFU (B)) were also tested. A three-point bending test and a tensile test with notchless prism-shaped specimens were conducted using a universal testing machine (AUTOGRAPH AG-IS, Shimadzu). A water absorption test was also carried out after the specimens were stored in water for 24h or 1 week. Flexural strength and fracture toughness were obtained by conducting a three-point bending test.

Results: TRINIA L and LR groups showed significantly high flexural strength (254.2±22.3 and 248.8±16.7MPa, respectively). Those were approximately 2.5 times higher than those in AL, E, and B groups (96.8-98.0MPa) (p<0.05, ANOVA and Tukey HSD test). No significant difference was shown in flexural modulus among the experimental groups. The fracture toughness in L group (9.1±0.4MPa/m^1/2) was found to be significantly higher than those in other groups (1.9-3.0MPa/m^1/2; p<0.05). TRINIA group demonstrated significantly lower water absorption (4.7±1.9μg/mm³) than did E (16.1±3.1μg/mm³) and B (17.3±3.7μg/mm³) groups (p<0.05).

Significance: TRINIA demonstrated distinct anisotropy. TRINIA can be used as a superior restorative material when specifying directions of its fiber mesh layers.

Keywords: Fiber-reinforced; Flexural strength; Fracture toughness; Resin composites; Water absorption.