Self-adhesive resin cements present a higher degree of conversion and faster polymerization kinetics when exposed to tooth temperature rather than to room temperature. Clinicians may expect differences in product setting time and some physical properties compared with what manufacturers report. SUMMARYObjectives: This study evaluated the degree of conversion (DC) of two commercial, self-adhesive resin cements (SARCs) using Fourier transform infrared analysis (FTIR) polymerized at simulated prepared tooth surface temperatures and under different curing conditions. Materials and Methods: RelyX U100 (U100, 3M ESPE) and Maxcem Elite (MX, Kerr Corporation) were mixed at 258C and applied to the surface of a horizontal attenuated total reflectance (ATR) unit, which was near room temperature (RT, control) (258C) or heated to simulate prepared tooth surface temperatures (288C and 328C) and then attached to an infrared spectrometer. The products were polymerized using one of three conditions: direct light exposure through a glass slide (DLE), exposure through a 1.5-mm thick ceramic disc overlay , 2014, 39-2, 204-212 (CO) (A2 shade, IPS e.max, Ivoclar Vivadent), or self-curing (SC). FTIR spectra were recorded for 12 minutes (1 spectrum/s, 16 scans/ spectrum, resolution 4 cm À1 ) immediately after application to the ATR. The DC was calculated using standard techniques of observing changes in aliphatic-to-aromatic peak ratios before and 12 minutes after curing, as well as during each 1-second interval. DC data (n=7) were analyzed by two-way analysis of variance and Tukey's post-hoc test (p=0.05).Results: Both simulated tooth temperatures significantly increased DC in all groups of MX and in the CO and SC groups of U100 compared with the RT control. For MX, the self-cure groups exposed to tooth temperatures showed DC values similar to those of the CO groups. For U100, the CO groups showed higher DC values than SC groups regardless of temperature. Time-based conversion profiles ranged according to product, temperature, and curing mode.Conclusions: Causing SARCs to polymerize at simulated tooth temperatures increases DC of SARCs compared with room-temperature curing values, mainly in the SC mode.

The structure of aluminum monohydroxide resulting from synthesis by ammonium hydroxide with aluminum chloride (or aluminum nitrate, for example) by a sol-gel process, gives a purified and chemically inert material with many applications possibilities because of its great specific surface area. A pseudoboehmite is the choice in this project for adsorption/desorption of atenolol. The molecular interaction with the pseudoboehmite substrate was studied by FTIR (Infrared Spectroscopy), DSC (Scanning electron /TG Thermogravimetry), UV-vis (Ultraviolet-visible spectroscopy) and SEM (Scanning Electron Microscopy). The SEM characterization has been used to quantify the local structural surface for the correlations with the synthesis process; and the Spectroscopies and Thermogravimetric techniques were used for measurements of the adsorption/desorption concentrations of the drug in physiological solution. This procedure gives information to the chemistry and surface of these fine ceramics material that would be applied like excipient in medications to control the drug delivery and plasmatic concentrations in optimal conditions.

The production of confined or adsorbed drugs in inorganic matrix has been increasing in areas like material science and pharmaceutical due to the possibility of the production of nanoadsorbed or encapsulated molecules with new properties like chemical stability, enhancing solubility and controlled release, what implies in new applications of materials. In the present work, a nanocomposite of a fine ceramic material, pseudoboehmite, and acyclovir, was prepared. Pseudoboehmite is based on a monohydroxide aluminum oxide produced from a synthetic route using ammonium hydroxide and aluminum nitrate or chloride as precursors in the sol-gel process. These systems had been characterized by the following techniques: MEV, TG/DSC, FTIR and UV-vis. The exposition of the drug to the pseudoboehmite at the dissolution equipment was at 37°C and 100rpm for 30 minutes. With the purpose to observe the interaction of the drug with the adsorbent, it was obtained the concentration of the drug in the solution, before and after the adsorption, using the UV-vis spectroscopy technique. The acyclovir has increased its solubility in an HCl 0,1M solution, when the weight ratio of Pseudoboehmite: Acyclovir 1:1 was used.

The developing of nanosystems has been intensely studied because of their efficiency when applied to pharmaceutical excipients, frequently called as drugs delivery systems. Sol-gel obtained pseudoboehmite, a fine synthetic ceramic precursor of alumina, shows itself as very promising due to its adsorption/desorption properties with pharmaceutical molecules. The use of factorial planning of two levels is very effective in preliminary studies about the possible influence of specific factors in the reagent conversion to a product. A method of pseudoboehmite obtainment was adopted, that has been already reported. The factorial planning 2³ used for the pseudoboehmite synthesis involved three variables of synthesis: temperature (A), the aluminum nitrate (Al (NO3)3·9H2O) concentration (B) and the ageing time (C). The X-ray diffraction data shows that the aging time has influence in the crystalinity of the synthesis product.

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