PURPOSE Although dental impression disinfection is determinant to reduce the cross-infection risk, some studies have shown that, in real practice, the disinfection procedures vary considerably. Thus, the aim of this study was to evaluate the antimicrobial effectiveness and the impact on the dimensional stability of addition silicone' impressions of water wash and the most clinically used disinfection solutions: 3% hydrogen peroxide, commercial disinfectant MD520 (Durr) and 1% and 5.25% sodium hypochlorite. MATERIALS AND METHODS For this investigation, dental impressions were taken on 16 volunteer dental students. The antimicrobial effectiveness of each procedure was evaluated by pour plate method. The dimensional stability was evaluated using a standardized stainless-steel model, according to ANSI/ADA nº19 specification. RESULTS The study results showed that water wash does not alter the dimensional stability of addition silicone impressions but doesn't reduce the microbial load of the material ( P >.05). On the other hand, addition silicone disinfection by immersion with 3% hydrogen peroxide, MD520 (Durr), or sodium hypochlorite at 1% and 5.25% does not alter the dimensional stability significantly but reduces > 99.9% of the microbial load of the impressions ( P <.001). CONCLUSION Addition silicone impressions should always be disinfected after water wash in order to reduce effectively the cross-infection risk. All disinfectants tested showed high antimicrobial efficiency without significant changes in three-dimensional shape of impressions. Hydrogen peroxide and sodium hypochlorite are of particular importance because are easily accessible in dental setting. The less explored hydrogen peroxide could be a valuable alternative for silicone impressions disinfection.

The HFT, using the FC, proved to be a minimally invasive technique that statistically inhibited tumour growth. Results suggested that this methodology seems to be a promising technique for the treatment of solid tumours, allowing repeated low hyperthermia treatments, which can be easier and less traumatic than other hyperthermia techniques.

The cancer treatment by local hyperthermia, using a high frequency electromagnetic field is an extensively studied subject. For this propose it was developed a ferrimagnetic cement (FC) to be injected directly into the tumor. In this study it was determined the FC injectability, its capability to generate heat when placed within a magnetic field and its interaction with a modified simulated body fluid using SEM/EDS and XRD. The FC biological response was assessed by the intramuscular implantation in rats and histological analysis of the surrounding tissues. The results suggest that FC can be injected directly into the tumor, its temperature can be increased when exposed to a magnetic field and the surface of the immersed samples quickly becomes coated with precipitate denoting its ionic change with the surrounding medium. The histological analysis revealed a transient local inflammatory reaction, similar to the control material, only slightly more abundant during the first weeks, with a gradual decrease over the implantation time. Based on these results, we concluded that FC might be useful for highly focalized thermotherapy, with a good potential for clinical use.

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