The effect of custom adaptation and span-diameter ratio on the flexural properties of fiber-reinforced composite posts.

OBJECTIVES

To evaluate whether custom modification resulting in an anatomically shaped post and whether the span/diameter ratio (L/D) would affect the mechanical properties of fiber-reinforced composite posts.

METHODS

Preformed glass-fiber posts (Group 1) and modified glass-fiber posts (Group 2) and glass-fiber rods (Groups 3 and 4) (n=20) were loaded to failure in a three-point bending test to determine the maximum load (N), flexural strength (MPa) and flexural modulus (GPa). The span distance tested for Group 3 was 10.0mm, while for Group 4 was 22.0mm. Data were subjected to different statistical analysis with significance levels of P<0.05.

RESULTS

The maximum load recorded for Groups 1 and 2 was 72.5+/-5.9N and 73.4+/-6.4N respectively, while for Groups 3 and 4 was 215.3+/-7N and 156.6+/-3.6N respectively. The flexural strength for Groups 1 and 2 was 914.6+/-53.1MPa and 1069.2+/-115.6MPa, while for Groups 3 and 4 was 685.4+/-22.2MPa and 899.6+/-46.1MPa. The flexural modulus recorded for Groups 1 and 2 was 32.6+/-3.2GPa and 33.4+/-2.2GPa respectively, while for Groups 3 and 4 was 13.7+/-0.3GPa and 34.4+/-0.3GPa respectively.

CONCLUSIONS

The flexural properties of an anatomically custom modified fiber post were not affected by the modification procedure and the span-diameter ratio is an important parameter for the interpretation of flexural strength and flexural modulus values.