Transformation from calcium sulfate to calcium phosphate in biological environment

Abstract

The formation of a nano-apatite surface layer is frequently considered a measure of bioactivity, especially for non-phosphate bioceramics. In the present study, strontium-doped calcium sulfate, (Ca,Sr)SO4, was used to verify the feasibility of this measure. The (Ca,Sr)SO4 specimen was prepared by mixing 10% SrSO4 by weight with 90% CaSO4·½H2O powder by weight. A solid solution of (Ca,7.6%Sr)SO4 was then produced by heating the powder mixture at 1100 °C for 1 h. The resulting (Ca,Sr)SO4 specimen was readily degradable in phosphate solution. A newly formed surface layer in the form of flakes was formed within one day of specimen immersion in phosphate solution. Structural and microstructure–compositional analyses indicated that the flakes were composed of octacalcium phosphate (OCP) crystals. An amorphous interface containing OCP nanocrystals was found between the newly formed surface layer and the remaining (Ca,Sr)SO4 specimen. The specimen was also implanted into a rat distal femur bone defect. In addition to new bone, fibrous tissue and inflammatory cells were found to interlace the (Ca,Sr)SO4 specimen. The present study indicated that a more comprehensive evaluation is needed to assess the bioactivity of non-phosphate bioceramics.

Treatment effects of two pedicle screws techniques strengthened by bone cement on old patients suffering from osteoporosis and lumbar spinal stenosis

“…It takes 8-24 weeks for calcium sulfate to be fully absorbed and replaced by autogenous bone, the speed of absorbing depends on lling part, range, lling amount and blood supply condition of local tissues [5] . It has been revealed in studies [6] that the degradation and absorption curve of calcium sulfate is similar to bone growth curve.…”

Sert Doku Uygulamaları İçin Makro Gözenekli Alüminyum Oksit-Bor Karbür Seramikleri

“…Bioceramic materials, which are made of ceramics that are biocompatible with the body, have a wide range of medical applications and can vary in their level of reactivity with biological tissues, from inert to active (Öksüz et al, 2023). Bioactive materials interact with body tissues through chemical bonding (Silva et al, 2022), while biodegradable bioceramics serve as a temporary scaffold to allow the regeneration of new bone tissue, after which they are naturally replaced by the body without requiring removal surgery (Chen et al, 2021). In contrast, bioinert materials do not have any chemical interaction with the biological environment or the body tissue, but they play a crucial role in bone implants due to their superior mechanical properties and high chemical stability (Kido et al, 2013).…”