A Novel Micro/Nano-Roughened Self-Glazed Zirconia Implant With Enhanced Osseointegration and Satisfactory Soft Tissue Sealing: An In Vitro and In Vivo Study

Objectives This study aimed to develop a novel self-glazed zirconia (SZr) dental implant featuring micro/nano-roughened thread and polished neck, and to examine its properties both in vitro and in vivo. Material and Methods The micro/nano-roughened SZr surfaces (SZr-MN) were manufactured using sandblasting and chemical vapor deposition. Surface topography, elemental composition, roughness, and contact angle were systematically characterized. Streptococcus mutans and Porphyromonas gingivalis were used to evaluate bacterial adhesion. Bone marrow mesenchymal stem cells (BMSCs) and human immortalized keratinocytes were used to assess cell adhesion, proliferation, and osteogenic differentiation. The sandblasting large-grit acid-etching treated titanium (Ti) surfaces (Ti-SLA) served as the control. Ti and SZr implants were inserted into the mandibles of Beagle dogs, followed by radiological, fluorescent, and histomorphometric analyses after 8 and 12 weeks of healing. Results The SZr-MN surface exhibited micro-scale ravines and gullies densely covered with curled, sheet-like nano-structures, which led to suitable roughness and improved hydrophilicity. Compared to the Ti-SLA surface, the SZr-MN surface demonstrated significantly reduced bacterial adhesion, along with increased adhesion and osteogenic differentiation of BMSCs. Consequently, the SZr implant achieved more extensive and denser surrounding bone tissue and enhanced osseointegration compared to the Ti implant, while both showed comparable dimensions of peri-implant soft and hard tissues. Conclusions The novel SZr implant surfaces demonstrated excellent antibacterial activity, biocompatibility, and proosteogenic effect, leading to enhanced osseointegration and satisfactory soft tissue sealing. Our findings offer a unique perspective on improving the biological activity of zirconia dental implants.