The retention of prefabricated glass fiber posts used on the restoration of endodontically-treated teeth is based on adhesive systems and resin luting cements. The type of posts used, as well as the type of activation of the cement can also influence this retention, mainly in areas more critical of the radicular dentin, such as the apical root segments, where there is a great difficulty of access of the light curing units. Thus, the purpose of this study will be to evaluate the influence of different self-adhesive luting systems (self-adhesive chemical activation - Multilink; self-adhesive dual cure - Panavia F2.0 and self-adhesive trial cure - Rely-X Unicem) in relation to the conventional chemical activation (C&B Cement) and to the dual cure resin cement (Rely-X ARC), on the extrusion (push-out) of glass fiber posts on the different thirds of the root (cervical, medium and apical). The influence of the light curing unit will be evaluated by the use of the halogen LCU (Optilux 501) and LED LCU (LEC II 470). The interface resinous cements/posts will be evaluated through scanning electron microscopy (SEM) and subsequent photomicrography descriptive analysis. Disks of the samples (n=168) will be used, with approximately 1 mm of thickness of 56 bovine roots restored with glass fiber posts. A universal testing machine will be used (Instron 4411, Instron Corporation, Norwood, USA) with a 1 mm diameter steel rod at cross-head speed of 0,5 mm/min until post extrusion with load cell of 50 kg, for evaluation of the push-out strength on the different thirds of each sample. The push-out strength values in kgf will be converted for MPa and analyzed through Analysis of Variance and Tukey’s test, with significant level of 5%.
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