Papers by Author: Claudia P. García

Abstract: Sol-Gel coatings are a good choice for protection and bioactivation of metals used as dentistry and standard surgical implant materials. These films should both prevent degradation of the substrates by wear or corrosion, and bioactivate the material for inducing the formation of a hydroxyapatite (HA) rich layer onto the material surface, thereby permitting a natural bonding to living tissues. The aim of this work was to estimate the clastogenicity in vitro by Single Cell Gel lectrophoresis Assay (SCGE) or “comet” assay of coatings of TiN applied by magnetron sputtering and of hybrid layers obtained by Sol-Gel containing glass, glass-ceramic and HA particles on stainless steel AISI 304. Six test specimens were prepared: AISI 304 Stainless Steel coated with an hybrid silica single film (SF), applied by sol-gel process, AISI 304 SS coated with double film with bioactive glass (DFG), glass-ceramics (DFGC) and HA (DFHA) particles, AISI 304 SS coated with TiN multi films (MFTiN) applied by PVD and bare AISI 304 SS (304SS). Significantly lower DNA migration (p>0.005) was observed in the cells of the cultures corresponding to the samples coated with SF, DFG, DFGC, DFHA and MFTiN respect to the bare 304 SS. The comparison between negative control and the same coated samples did not reveal any statistically significant difference (p>0.005) in clastogenicity in vitro evaluated by SCGE.

Abstract: The synthetic hydroxyapatite is a very useful material for numerous applications in medicine as a biomaterial. One of the most economic manufacturing process is the precipitation route. In the present work, synthetic hydroxyapatite was prepared using the precipitation route, starting with aqueous solutions of calcium nitrate (Ca(NO3).4H2O ) and ammonium phosphate (H2(PO4)NH4). The effects of physical-chemical variables such as pH, temperature, time of agitation, ageing time and heat treatment of the mixture were evaluated. The characterization of the samples obtained in different conditions made possible to conclude about the optimal values of the studied variables for the synthesis of this material in laboratory conditions.