Recent advances in silicate-based crystalline bioceramics for orthopedic applications: a review

The present article critically reviewed the potentiality of Mg–Ca silicate-based crystalline bioceramics such as MgSiO₃, Mg₂SiO₄, CaSiO₃, Ca₂SiO₄, Ca₃SiO₅, CaMgSi₂O_6, Ca₂MgSi₂O₇, Ca₇MgSi₄O₁₆, CaMgSiO₄ and Ca₃MgSi₂O₈ as new generation orthopedic prosthetic implants. Mg²⁺, Ca²⁺ and Si⁴⁺ ions are abundant in bone and play a crucial role in various bone metabolic activities such as enhancing osteogenesis and inhibiting osteoporosis. The release rate of Mg²⁺, Ca²⁺ and Si⁴⁺ ions from these bioceramics depends on the crystal structure which consequently, influences their bioactivity and biocompatibility. In addition, the release rate of these ions can be tuned by tailoring the processing parameters/routes and compositional modifications and subsequently, bioactivity, cellular response as well as bone regeneration ability can be improved. Toward this end, the present article thoroughly reviewed and analyzed the influence of crystal structure, processing parameters/routes and compositional alteration on in vitro/in vivo biocompatibility and degradation behavior of the above ceramics. Further, a correlation between structure, processing and properties has been established.