RESUMO
AIM: To synthesize and characterize zinc oxide (ZnO) nanocrystals and assess their biological properties for applications in dentistry, particularly in endodontics, by means of intraosseous implants. METHODOLOGY: ZnO nanocrystals were synthesized and characterized by micro-Raman spectroscopy and X-ray Diffraction. Ten guinea pigs were divided into two groups representing experimental periods of 4 and 12 weeks and received implants on both sides of the mandible in the region of the symphysis. The connective tissue response along the lateral wall outside the cup served as the negative control. The animals were euthanized at the end of each observation period and prepared for routine histological examinations which evaluated inflammatory response and material biocompatibility. RESULTS: ZnO nanocrystals were highly pure, crystalline, and averaged 21 nm in size. After 12 weeks, tissue analysis revealed the presence of a thin layer of connective tissue with some giant cells between the implanted material and underlying bone tissue. While signs of mild inflammation could be seen, bone resorption and remodeling were not apparent. CONCLUSION: ZnO nanocrystals were biocompatible, well tolerated and allowed new bone formation and bone remodelling.
Assuntos
Materiais Biocompatíveis , Implantação Dentária Endóssea , Nanopartículas/química , Óxido de Zinco/química , Cristalografia por Raios X , Análise Espectral RamanRESUMO
AIM: To evaluate the biological properties of a variety of materials that could be used in apical surgery. METHODOLOGY: The intraosseous implant technique recommended by the FDI (1980) and ADA (1982) was used to test the following materials: zinc oxide-eugenol (ZOE), mineral trioxide aggregate (MTA), and Z-100 light-cured composite resin. Thirty guinea-pigs, 10 for each material, divided into experimental periods of 4 and 12 weeks, received one implant on each side of the lower jaw symphysis. The connective tissue response alongside the lateral wall outside the cup served as a negative control for the technique. At the end of the observation periods, the animals were killed and the specimens prepared for routine histological examination to evaluate their biocompatibility. RESULTS: The reaction of the tissue to the materials diminished with time. The ZOE cement was highly toxic during the 4-week experimental period, but this profile changed significantly after 12 weeks, when it showed biocompatible characteristics. MTA and Z-100 showed biocompatibility in this test model at both time periods. CONCLUSIONS: MTA and Z-100 composite were biocompatible at 4 and 12 weeks in this experimental model.