| Objective The aim of this study was to investigate the flexural strength and the flexural modulus of 6 kinds root canal post and the bond strength of 2 kinds of fiber reinforced root canal post, and to provide theoretical ground for applying Pontic fiber post to clinical use.Methods (1) Pontic fiber posts were made by self-made glass pattern; (2) Pontic fiber posts were loaded to failure in a three-point bending test. The crosshead speed is 1.0 mm/min. The same test repeated with glass fiber posts, zirconia posts, Ni-Cr alloy cast posts, stainless steel posts and titanium posts; (3) Twenty extracted human maxillary central incisors were selected and then canines were endodontically treated. Following standardized post space preparations, teeth were divided into two equal groups, and then glass fiber posts and Pontic fiber posts were placed in the treated canines using Rely X Unicem. Three slices of 1.5mm height were cut perpendicular to the post from each restored root. The bond strength was determined by pushing out test. The crosshead speed is 0.5 mm/min. (4)Data were statistically analyzed using two-way analysis of variance(ANOVA) and one-way analysis of variance.Results (1) The ANOVA test analysis revealed significant differences between groups (P < 0.05) for flexural strength mean values. Yield flexural strength of the 6 kinds post as follows:Pontic fiber post were 585 to 616MPa, glass fiber post were 519 to 1081MPa, zirconia post were 939 to 1265MPa, stainless steel posts were 1649 to 2265Mpa, titanium posts were 1411 to 2156MPa, Ni-Cr alloy cast posts were 1336 to 1949MPa. (2)The ANOVA test analysis revealed significant differences between groups (P < 0.05) for flexural modulus mean values. Yield flexural modulus of the 6 kinds post as follows: Pontic fiber posts were 16 to 20Gpa, glass fiber posts were 21 to 36GPa, zirconia posts were 74 to 125GPa, stainless steel posts were 32 to 98GPa, titanium posts were 42 to 63GPa, Ni-Cr alloy cast posts were 34 to 98GPa. (3) The ANOVA test analysis revealed significant differences between the two group in mean bond strengths (P>0.05), the bond strength for glass fiber post was 8.61±3.33MPa, and for Pontic fiber post was 6.36±3.05MPa. At the coronal third, the ANOVA test analysis revealed significant differences between the two post, the bond strength of glass fiber post was 8.44±2.34MPa, that of Pontic fiber post was 4.19±1.22MPa (P < 0.05); at the middle third and the apical third, the ANOVA test analysis revealed no statistically significant difference in mean bond strengths (P>0.05), at the middle third, the bond strength of glass fiber post was 9.32±4.06MPa, that of Pontic fiber post was 6.79±2.96MPa; at the apical third, the bond strength of glass fiber post was 8.08±3.61MPa, that of Pontic fiber post was 8.13±3.32MPa.Conclusions (1) The metal post has the highest flexural strength recorded, the next is zirconia post, fiber post is lower. Flexural strength of the 6 kinds post can meet clinical requirement. (2) Zirconia post had the highest flexural strength recorded, the next is those metal post, fiber post is lower. The flexture modulous of fiber post is more matching that of dentin. (3) Using Rely X Unicem, both glass fiber post and Pontic fiber post form good bond strength to dentin.
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