Natural Rubber Latex (NRL) can be used successfully in controlled release drug delivery due to their excellent matrix forming properties. Recently, NRL has shown to stimulate angiogenesis, cellular adhesion and the formation of extracellular matrix, promoting the replacement and regeneration of tissue. A dermatological delivery system comprising a topically acceptable, inert support impregnated with a metronidazole (MET) solution was developed. MET 2-(2-methyl-5-nitro-1H-imidazol-1-yl) ethanol, has been widely used for the treatment of protozoa and anaerobic bacterial infections. MET is a nitroimidazole anti-infective medication used mainly in the treatment of infections caused by susceptible organisms, particularly anaerobic bacteria and protozoa. In a previous study, we have tested NRL as an occlusive membrane for GBR with promising results. One possible way to decrease the inflammatory process, it was incorporated the MET in NRL. MET was incorporated into the NRL, by mixing it in solution for in vitro protein delivery experiments. The solutions of latex and MET were polymerized at different temperatures, from -100 to 40 °C, in order to control the membrane morphology. SEM microscopy analysis showed that the number, size and distribution of pores in NRL membranes varied depending on polymerization temperature, as well as its overall morphology. Results demonstrated that the best drug-delivery system was the membrane polymerized at -100 °C, which does release 77,1% of its MET content for up 310 hours.

Using an experimental model and PENELOPE Monte Carlo simulations, the effects of resin and amalgam on the absorbed doses in tooth enamel were studied to evaluate the feasibility of using restored teeth in electron spin resonance (ESR) dose reconstruction. The model consisted of a phantom containing a plate of these restorative materials placed between powered enamel layers exposed to X rays and a ⁶⁰Co beam. The experimental results and simulations agreed, showing that the attenuation produced by amalgam and resin with a thickness of 1, 2, and 4 mm is similar to that produced by the enamel itself in the case of the radiation sources employed. For X rays and ⁶⁰Co γ radiation the attenuation reached almost 100% and 40%, respectively. These results show that for ESR dose reconstruction, the use of all available enamel of a tooth leads to errors in the estimated dose due to attenuation effects in both healthy and restored teeth. Thus the importance of an enamel selection from different sides of the tooth surface to apply ESR dose reconstruction in the case of a practical situation is shown.

Abstract:The tissue reaction of bone tissue accessed by light microscopy and scanning electron microscopy (SEM) images after polyurethane resin implantation is presented in this study. Twenty four male rabbits were used, divided into two groups of 12 animals each (experimental group and control group) in which full-thickness cranial defect was surgically created. At 30 and 90 days post operation 6 animals of each group were euthanized and bone samples were removed for analysis. The microscopic results indicated no inflammatory foreign body reaction, a perfect union between the polymer and surgical bone bed surface, lack of bone resorption and presence of a thin layer of osteogenic material covering the polymer surface in contact with the surgical bone bed. The SEM images demonstrate the porosity of the resin, with diameters from 120 to 500 µm. This important feature of this polymer is associated with its osteoconductivity, allowing the bone growth inside it, improving the integration between the material and bone tissue. These results confirm that polyurethane resin derived from Ricinuscommunis is an excellent bone substitute for use in repair surgery for great bone losses.

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