In-vitro characterization and evaluation of innovative surface modifications of zirconia implants for the optimization of hard and soft tissue management

PURPOSE: This study focuses on the characterization and evaluation of innovative surface modifications of zirconia implants aimed at optimizing hard and soft tissue management. METHODS: The cytocompatibility of newly developed ceramic implant coatings was assessed. Five different surface types were investigated: uncoated zirconia (Zr), zirconia coated with pure titanium (ZrTi), zirconia coated with calcium phosphate (CaP), zirconia coated with hydroxyapatite (HA) and zirconia coated with calcium phosphate-hydroxyapatite (CaP/HA). Cytocompatibility was assessed using L929 mouse fibroblasts and MC3T3 pre-osteoblasts. Testing was performed in both direct and indirect cell contact with the materials. In the direct contact setup, cells were cultured for 24 h on the test surfaces, followed by live/dead staining and fluorescence microscopy. In the indirect setup, material extracts were prepared and cell viability was quantified after 72 h using lactate dehydrogenase (LDH) and cell proliferation (XTT) assays. RESULTS: All tested surfaces demonstrated good cytocompatibility without significant cytotoxic effects. Supplementary scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses confirmed the successful application of the coatings and provided detailed insight into surface topography and elemental composition. CONCLUSION: Calcium phosphate and hydroxyapatite-coated zirconia implants represent a promising biocompatible alternative to titanium-based surfaces, with the potential to improve tissue integration and long-term clinical outcomes in ceramic dental implantology.