Methods: Prefabricated glass fiber posts (PE; FibreKor Post, Pentron Japan) and experimental posts (EX) were subjected to a three-point bending test (span 10 mm, crosshead speed 1.0 mm/min) using a universal testing machine (AUTOGRAPH AGS-H, Shimadzu Japan). Flexural modulus were calculated and statistically analyzed (one-way ANOVA, Tukey HSD, p<0.05). Eighteen human extracted lower premolars were randomly diveded into three groups. Twelve premolars were sectioned at cement-enamel junction, endodontically treated and prepared post space (φ1.5 mm, depth 8 mm). The specimens were fabricated with PE and EX (length 11 mm, n=6) and composite resin core (Clearfil DC Core Automix, Kuraray Medical Inc.). Height of core was adjusted to 5 mm and the edge of the abutment was cut at 45° to the long axis of the root to apply the load. Six teeth remained untreated and were prepared with the same shape of the composite resin abutment using a diamond bur (PZ). Fracture strengths were determined using a universal testing machine at crosshead speed of 1.0 mm/min. The data were statistically analyzed (one-way ANOVA, Tukey HSD, p<0.05).
Results: Flexural modulus (GPa) of PE, EX were 27.6±0.59, 4.25±0.17, respectively. PE showed higher flexural modulus than EX (p<0.05). Fracture strengths (N) of PE, EX, PZ were 844.3±217.9, 931.7±326.5, 1557±296.9, respectively. PZ showed higher fracture strength than PE, EX (p<0.05).
Conclusion: In this study, EX has the similar fracture strength to PE. EX can be probably used in clinically.