Bis-GMA/TTEGDMA-based resin composites were prepared with two different types of nanoclays: an organically modified laminar clay (Cloisite® 30B, montmorillonite, MMT) and a microfibrous clay (palygorskite, PLG). Their physicochemical and mechanical properties were then determined. Both MMT and PLG nanoclays were added into monomer mixture (1:1 ratio) at different loading levels (0, 2, 4, 6, 8 and 10 wt.%), and the resulting composites were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and mechanical testing (bending and compressive properties). Thermal properties, depth of cure and water absorption were not greatly affected by the type of nanoclay, while the mechanical properties of dental resin composites depended on both the variety and concentration of nanoclay. In this regard, composites containing MMT displayed higher mechanical strength (both flexural and compression) than those resins prepared with PLG due to a poor nanoclay dispersion as revealed by SEM. Solubility of the composites was dependent not only on nanoclay-type but also the mineral concentration. Dental composites fulfilled the minimum depth cure and solubility criteria set by the ISO 4049 standard. In contrast, the minimum bending strength (50 MPa) established by the international standard was only satisfied by the dental resins containing MMT. Based on these results, composites containing either MMT or PLG (at low filler contents) are potentially suitable for use in dental restorative resins, although those prepared with MMT displayed better results.

The aim of this work was to investigate the potential of low-generation polyamidoamine (PAMAM) dendrimers as drug nanocarriers for 5-fluorouracil (5-FU), an anticancer drug, and to determine the type of dendrimer generation (half or full) with the highest drug load capacity and slowest release rate. For this, PAMAM dendrimers (up to 2.0 generation) were synthesized and characterized by means of spectroscopic techniques and thermal analysis. Then, 5-FU was successfully incorporated into dendrimers, and the resulting complexes were characterized in terms of their, elemental composition, spectroscopy, thermal behavior, and loading efficacy. In addition, in vitro release studies of 5-fluorouracil from complexes were conducted using phosphate-buffered saline; and the 5-FU release kinetics was also modeled. The successful synthesis of PAMAM dendrimers was confirmed by Fourier transform infrared spectroscopy (FTIR), 1 H-NMR, UV-vis, dynamic light scattering and thermogravimetric analysis (TGA) analysis. Energydispersive X-ray spectroscopy (EDX), FTIR, UV-vis and TGA results confirmed the complexation phenomena among PAMAM dendrimers and 5-FU drug. It was found that the encapsulation efficiency and drug release rate are a function of generation type, and that the full-generation dendrimers showed the best results. The Korsmeyer-Peppas model best described the kinetics of drug release for all complexes. These results confirm that the proposed low-generation dendrimers are suitable polymeric nanocarriers for drug delivery applications.