Improving the osseointegration and soft tissue sealing of zirconia ceramics by the incorporation of akermanite via sol infiltration for dental implants

Abstract

Zirconia ceramics are promising dental implant materials due to their high-grade biocompatibility, high mechanical strength, and distinctive aesthetic appearance. Nevertheless, zirconia ceramics are bio-inert with a lack of osseointegration and soft tissue sealing, which limits dental implant applications. As such, the fabrication of zirconia ceramics with high mechanical strength, excellent osseointegration and soft tissue sealing performance remains a great challenge in the dental restoration field. In this article, a novel zirconia ceramic with akermanite (AKT) modification by the negative pressure infiltration method is presented. The effects of AKT sol infiltration at different times on the morphology, phase composition, mechanical properties, bioactivity, osseointegration and soft tissue sealing of the modified zirconia ceramics have been systematically investigated. The modified zirconia ceramics feature excellent mechanical properties and significantly improved surface roughness, hydrophilia, and apatite mineralization ability as compared with unmodified zirconia ceramics. Furthermore, cell-culture experiment results indicated that the surface modification of zirconia ceramics could promote adhesion, spreading, migration, proliferation and osteogenic differentiation of mouse bone marrow stromal stem cells (mBMSCs), as well as the early adhesion, spreading, proliferation and fibroblast differentiation of human gingival fibroblasts (HGFs) in vitro. The prepared bioactive zirconia distinctively enhanced the alkaline phosphate (ALP) activity, osteogenesis-related gene expression of mBMSCs and fibroblast-related-gene expression of HGFs. The in vivo evaluation confirmed that 15-TZP ceramics could promote bone-implant osseointegration to the greatest extent as compared with pure zirconia ceramics. To conclude, our research has shown that AKT-modified zirconia ceramics can achieve bone integration and soft tissue sealing, indicating that they have a lot of potential for application as a novel dental implant material in the clinical setting.