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Abstract

The rate of in vivo degradation and level of bioactivity of bioactive glasses are composition dependent [1]. By altering bioactive glass composition, the rate of resorption can be controlled. The network connectivity of a glass can be used to predict various physical properties of the glass including its solubility and, hence, its bioactivity [2]. Glass solubility increases as network connectivity is reduced. Glasses in the soda-lime phosphosilicate system were studied. The initial choice of composition was based on phosphate content and low network connectivity. A systematic substitution of calcium oxide for sodium oxide on a molar basis was made in order to examine the influence of sodium oxide content on the glass properties while keeping the network connectivity constant. The glass transition temperature and the peak crystallization temperature were seen to decrease linearly with increasing sodium oxide content. Thermal expansion coefficient and glass density were also seen to be related to sodium oxide content. Preliminary in vitro biocompatibility studies revealed that the glasses of higher sodium oxide content were associated with a cytotoxic response. The measurement of media pH indicated that this cytotoxic effect was due to ion exchange reactions at the glass surface.

Bioactive glass engineered coatings for Ti6Al4V alloys: Influence of strontium substitution for calcium on sintering behaviour

“…This phenomenon appears to be a characteristic of bioactive glasses. It has been observed in a number of previous studies [10,34] and is related to the particle size effects on heat transfer [35].…”

Influence of magnesia on the structure and properties of bioactive glasses

“…** Fig It is suggested that magnesium suppresses crystallisation. Crystallisation of a bioactive glass is known to inhibit its bioactive properties due to the lower reactivity of the crystalline state and increased resistance to the ion exchange reaction [59].…”

Processamento e caracterização de espumas vitrocerâmicas do sistema sncp (Sio2-Na2o-Cao-P2 O5)

“…A Figura 6 24 Para comprovar este fato, tanto o vidro como a espuma foram imersos em água durante 28 dias a 37 ºC em estufa. Foi possível observar um aumento no valor de pH de 10 para 12,4, o que comprova o consumo de H + do meio.…”