Radicular peroxide penetration from carbamide peroxide gels during intracoronal bleaching.

AIM: To evaluate and compare radicular peroxide diffusion from different concentrations of carbamide peroxide bleaching gels. METHODOLOGY; Fifty maxillary premolar teeth were separated into five groups (n = 10). Standardized endodontic access cavities were prepared in the occlusal surfaces, and the root canals were prepared using a step back technique and filled using the lateral compaction technique. The gutta-percha filling was removed 4 mm short of the cemento-enamel junction (CEJ) and a 2-mm-thick glass-ionomer cement base was placed. Outer root surfaces were sealed with wax and nail polish, leaving the coronal third of the tooth and the CEJ exposed. All teeth were immersed in a plastic tube containing 2 mL of distilled water, and the experimental groups were treated with a bleaching agent of either 10%, 17% or 37% carbamide peroxide (CP) or a mixture of 30% hydrogen peroxide (HP) and sodium perborate (SP) placed into the coronal pulp chamber of teeth and left for 24 h. Peroxide penetration was measured using the ferrothiocyanate method. Statistical analysis of data was conducted by using the Kruskal-Wallis Analysis of Variance and Mann-Whitney U test. RESULTS: Higher peroxide penetration occurred with the 30% HP-SP mixture than with the CP bleaching gels, and the 37% CP group also promoted greater peroxide penetration than the other CP groups (P < 0.05). There was no statistically significant difference between 10% and 17% CP groups (P > 0.05). CONCLUSION: Peroxide penetration of CP gels was significantly lower than that of a HP-SP mixture.

Comparison of biodegradable nanoparticles and multiple emulsions (water-in-oil-in-water) containing influenza virus antigen on the in vivo immune response in rats.

Multiple water-in-oil-water (w/o/w) emulsion and polymeric nanoparticle formulations containing influenza virus surface antigen hemagglutinin (HA) are thought to be suitable carriers for a vaccine delivery system. The multiple emulsion technique leads to high entrapment of HA, while the solvent evaporation technique encapsulates and adsorbs HA within the nanoparticle. Immune responses of these formulations were investigated in rats and compared with the immune response raised against the conventional vaccine. The responses were detected with the hemagglutinin inhibition (HAI) assay. A single administration of multiple emulsion (F1, F2, F3) and nanoparticle (F4) formulations proved to stimulate a more effective immune response in rats than conventional vaccine.