Comparison in in-vivo response between a bioactive glass and a non-bioactive glass

The authors report on the in-vivo comparison, in the rabbit, between the response to a bioactive glass and the response to a non-bioactive glass. Implants have been performed in muscle and bone. Two different glasses were investigated, namely B01 and I02. B01 is a glass designed to be degradable and resorbable and has a percentual molar composition of: SiO₂ 49.6%; P₂O₅2.7%; CaO+MgO+Na₂O+K₂O+Al₂O₃ 47.7% with a 1:1 CaO/Na₂O ratio. I02 is a sodium-calcium-silicate non-resorbable glass lacking P₂O₅ and has a percentual molar composition of: SiO₂ 70.7%; CaO+MgO+Na₂O+K₂O+Al₂O₃ 29.3%. In-vivo tests were planned as: (a) intramuscular implants of glass cylinders in the rectus femoris and retrievals took place at 2, 16 and 43 weeks; (b) intraosseus implants of glass cylinders in the distal femural canal and retrievals took place at 8 and 43 weeks. Histology and light microscopy analysis followed. Bioactive degradable glass elicits a favorable response both in muscle and bone; a gradual degradation process leads to disruption and partial resorption of the material and a tight apposition is promoted with the newly formed bone. The non-bioactive sodium-calcium-silicate glass (named I02) may elicit, like the bioactive degradable B01, favorable response which is characterized by the absence of inflammatory or other adverse reactions; anyway it does not change its structure at an optical microscopic level and it does not promote any tight apposition with bone.