Active materials inducing calcium-phosphate precipitation for the treatment of bone defects.

Active glasses are materials that, when implanted in bone, degrade releasing ions that can positively interact with the bony cells stimulating the osteogenesis. This phenomenon regards two different aspects: the biological and the chemical-physical one. Glassy granules of different compositions were implanted in rabbit\u2019s muscles and sheep\u2019s mandibular bone at different times. After the animals\u2019 sacrifice particles with the surrounding tissues were explanted, fixed and embedded in PMMA. Sections were prepared for the scanning electron microscopy. The observations showed that the glass with the less amount of silicon degrades in a shorter time than that with the higher content. In sheep`s mandibular bone, the glassy particles with 52 and 55% molar weight content in silicon, degrade and on the surface of glass little needles of precipitates appear. The EDS analyses show that they are composed of Calcium and Phosphorus with a P content greater than that of HA of bone. New bone trabeculae surrounds the granules