Effect of Forming Process on Flexural Properties of Posts Reinforced with Poly p-Phenylene-2,6-Benzobisoxazole Fibers

摘要

Purpose. To evaluate the effect of various forming process and fiber-reinforcement types on the flexural properties of endodontic post materials under static and fatigue loading. Methods. Test specimens (2 mm x 2 mm x 25 mm) (N = 10) of three different types of fiber-reinforcement (Q: quartz, UP: untreated PBO, TP: treated PBO) were prepared using either a pultrusion (P) or compression-molded processing (M) method. The flexural properties of the resulting fiber-reinforced composites were assessed. Data were analyzed using a two-way analysis of variance (forming process and fiber reinforcement type) and Tukey HSD post hoc tests (alpha = 0.05). Results. Two main factors (forming process and fiber reinforcement type) were found to be significant with regards to flexural strength and the numbers of cycles in fatigue testing (P < 0 05). The flexural strength achieved with compression molding was significantly lower than that with pultrusion (P < 0.05) with all three fiber reinforcement types. When the same forming process was used, the greatest flexural strength was obtained with quartz fibers, followed in order by treated PBO fibers and untreated PBO fibers. Pultrusion resulted in a higher resistance to cyclic loads than compression molding when the same fiber reinforcement (TP) was used (P < 0.05). Conclusions. Pultrusion increases flexural strength under static loading for all three fiber reinforcement types when compared to compression molding. Pultrusion also increases the resistance to fatigue loading, but only with quartz and treated PBO fiber-reinforced composites, and not with untreated PBO fibers.