Effect of calcium hydrothermal treatment of zirconia abutments on human gingival fibroblasts

Abstract

Zirconia materials have been increasingly used in implant rehabilitation due to their excellent physical and esthetic properties. Stable peri‐implant epithelial tissue adhesion to the transmucosal implant abutment may significantly enhance the efficacy of implant long‐term stability. However, it is difficult to form stable chemical or biological bindings with peri‐implant epithelial tissue due to the strong biological inertia of zirconia materials. In the present study, we investigated whether calcium hydrothermal treatment of zirconia promotes sealing of peri‐implant epithelial tissue. In vitro experiments were performed to analyze the effects of calcium hydrothermal treatment on zirconia surface morphology and composition by scanning electron microscopy and energy dispersive spectrometry. Immunofluorescence staining of adherent proteins, namely, F‐actin and integrin β1, in human gingival fibroblast line (HGF‐l) cells was performed. In the calcium hydrothermal treatment group, there was higher expression of these adherent proteins and increased HGF‐l cell proliferation. An in vivo study was conducted by extracting the maxillary right first molars of rats and replacing them with mini‐zirconia abutment implants. The calcium hydrothermal treatment group showed better attachment at the zirconia abutment surface, which inhibited horseradish peroxidase penetration at 2 weeks post‐implantation. These results demonstrated that calcium hydrothermal treatment of zirconia improves the seal between the implant abutment and surrounding epithelial tissues, potentially increasing the long‐term stability of the implant.