A Push-out Bond Strength Study and Interface Analysis of New Porous Titanium Dental Post Luted with Resin Cement This study aimed to compare the push-out bond strength (PBS) between a new porous titanium post (PTP) and other marketed dental posts cemented with two types of dual-cure resin cement. A total of 96 extracted single-rooted human teeth were recruited. Four types of dental posts (n = 24 each), namely: stainless steel post (SSP), commercially-pure titanium post (CTP), fibre glass post (FGP), and PTP were cemented with two types of resin cements (RelyX U200 and ParaCore) and then sectioned at coronal and middle root levels. The specimens were subjected to a PBS test at a crosshead speed of 0.5 mm/min. The interface analysis was performed using a stereomicroscope and scanning electron microscope. A p-value < 0.05 was considered significant for all statistical tests. PBS recordings showed that the highest PBS mean value in RelyX group was 2.68±1.10 MPa for PTP. The differences in PBS between PTP and SSP and FGP were not significant (p = 0.098 and p = 0.075, respectively). The null hypothesis for RelyX group at both coronal and middle sections of the root was retained (p > 0.05). No failure at the post-cement interface was found in the PTP group, which was founder superior over the other posts (no gap for this interface was observed). The PTP showed similar bonding strength and adhesion to the other tested posts when using RelyX U200 cement. The PTP can be considered a new alternative option for the dental post system.

Ten percent carbamide peroxide is an effective, safe home bleaching agent. Higher concentrations are more effective, but there are mixed reports on their hardness and surface roughness effects on resin composites. To evaluate the effect of home bleaching agents; Opalescence Now 10% carbamide peroxide (Ultradent Products, USA) and Perfect Bleach 17% carbamide peroxide (Voco, Germany) on the surface hardness of microhybrid resin composites; Filtek Z250 (3M ESPE, USA) and Point 4 (Kerr, USA) and their surface roughness of selected treatment. Thirty specimens were prepared using acrylic moulds (4mm diameter x 2mm thick). N=5 controls placed in distilled water for 14 days. N=5 treated with Opalescence, and n=5 treated with Perfect Bleach for 2 hours every day for 14 days. Surface hardness was tested using Vickers hardness tester FV-7 (Future Tech Corp, Japan). Data analyzed with Mann-Whitney test with (P<0.05) considered significant. One specimen from 10% carbamide peroxide group was randomly selected for surface roughness, (Ra) evaluation using Atomic Force Microscopy (Ambios Technology, California, USA). All tested materials showed no significant changes in surface hardness after 14 days bleaching with 10% and 17% carbamide peroxide. However, AFM evaluation revealed an increase in Ra in both composites with 10% carbamide peroxide. Fourteen days bleaching using 10% and 17% carbamide peroxide did not have different effect on the surface hardness of Point 4 and Filtek Z250. The Ra increased after bleaching in both composites. The AFM surface roughness evaluation observed in 3D images shows to be a promising technique.