In vivo behavior of bioactive phosphate glass-ceramics from the system P2O5–Na2O–CaO containing TiO2

Abstract

Soda lime phosphate bioglass-ceramics with incorporation of small additions of TiO2 were prepared in the metaphosphate and pyrophosphate region, using an appropriate two-step heat treatment of controlled crystallization defined by differential thermal analysis results. Identification and quantification of crystalline phases precipitated from the soda lime phosphate glasses were performed using X-ray diffraction analysis. Calcium pyrophosphate (beta-Ca2P2O7), sodium metaphosphate (NaPO3), calcium metaphosphate (beta-Ca(PO3)2), sodium pyrophosphate (Na4P2O7), sodium calcium phosphate (Na4Ca(PO3)6) and sodium titanium phosphate (Na5Ti(PO4)3) phases were detected in the prepared glass-ceramics. The degradation of the prepared glass-ceramics were carried out for different periods of time in simulated body fluid at 37 degrees C using granules in the range of (0.300-0.600 mm). The released ions were estimated by atomic absorption spectroscopy and the surface textures were measured by scanning electron microscopy. Evaluation of in vivo bioactivity of the prepared glass-ceramics was carried through implanting the samples in the rabbit femurs. The results showed that the addition of 0.5 TiO2 mol% enhanced the bioactivity while further increase of the TiO2 content decreased the bioactivity. The effect of titanium dioxide on the bioactivity was interpreted on the basis of its action on the crystallization process of the glass-ceramics.

Doping of a high calcium oxide metaphosphate glass with titanium dioxide

“…Unlike all other studied compositions, 5 mol% TiO 2 -containing glass showed two crystallization peaks. This finding suggested that TiO 2 could act as a nucleating agent and induce phase separation during cooling of the molten glass [13].…”

“…TiO 2 acts as a nucleating agent, and although it is miscible in the molten glass, it induces phase separation during cooling of the melt. It was observed that the addition of 0.5 mol% TiO 2 enhanced the bioactivity which started to decrease upon further increase of the TiO 2 content [13].…”

Titanium-containing bioactive phosphate glasses

“…The glass solubility also drives the extent to which new bone tissue may be formed around the implant, with lower dissolution rate titanium glasses being fully surrounded by new bone tissue whereas more soluble Tifree glasses show some voids and/or soft tissue formation. Increasing the TiO 2 content-again only up to around 5 mol%-yields improvements in terms of bone cell growth [110,119]. Thus, the results of numerous studies on titanium phosphate glass biocompatibility are highly encouraging.…”

Mineral status and mechanical properties of cancellous bone exposed to hydrogen peroxide for various time periods

“…However, they are brittle and lack tensile strength and plasticity. Moreover, their degradation behavior is hard to control (Monem et al 2008;Ogose et al 2006). Biocompatible polymers, such as poly-DL-lactic-co-glycolic acid and polyalpha-hydroxyl-acid, have also been regarded as candidates for tissue-engineered scaffolds (Ignatius et al 2001).…”