RESUMEN
Introduction: Fiber-reinforced composite posts (FRC posts) have been used for tooth reinforcement after endodontic treatment. The mechanical characteristics of FRC posts can influence the clinical prognostic. Objective:The aim of this study was to evaluate the flexural strength and fracture resistance of commercially available FRC posts. Material and methods: Fourteen human single-rooted premolars with completely formed apices were selected and received endodontic treatment. The specimens were divided into two groups related to the post system: i) Group A - cylindrical-conical fiber-reinforced post (White post DC, FGM), and ii) group B - conical fiber-reinforced post (EXACTO, Angelus). The fracture resistance was evaluated and two point bending tests were carried out. The glass fiber characteristics and the tag penetration of the luting material into the radicular dentin structure were evaluated through scanning electronic microscopy in an illustrative way. One-way ANOVA and Tukey's HSD test (α = 0.05) were applied. Results: The values obtained for fracture resistance and two point bending test were, respectively, 399.29 N and 109.5 N for group A, and 386.25 N and 119.5 N for group B. No significant differences in strength values among the groups were found. Conclusion: There were no significant statistical differences between the two post groups regarding to fracture strength and two point bending strength. It can be concluded that the posts selected for this study performed satisfactorily in terms of mechanical properties so that they can be used for tooth reinforcement after endodontic treatment.
RESUMEN
O objetivo deste estudo foi avaliar a produção de alginato por Pseudomonas mendocina à partir dos substratos glicerol, sacarose e glicose. Nessa etapa do estudo comparou-se o rendimento de bioconversão e a produtividade do processo fermentativo, além das características físico-químicas dos materiais produzidos à partir dos substratos utilizados. Os melhores resultados em termos de rendimento e bioconversão foram observados quando o biopolímero foi produzido tendo sacarose como fonte de carbono. Observou-se que os biopolímeros produzidos apresentaram composição química similar e que as características reológicas do meio de cultura dependem da fonte de carbono utilizada.