Comparative Animal Study of Zirconia-Coated Titanium Implants: Effect on Bone Formation and Collagen Fiber Orientation

Tissue responses to zirconia-coated implants treated with molecular precursor method were evaluated. The zirconia film was characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Cylindrical titanium (ZrO₂/Ti) specimens were sandblasted, acid-etched, and coated with zirconia using the molecular precursor method. Control specimens were sandblasted and acid-etched only (SLA/Ti). After maxillary first molar extraction, four ZrO₂/Ti and four SLA/Ti implants were placed in the alveolar bone of the rats, and tissue responses were observed after 3 weeks. Surface analysis using SEM and AFM showed zirconia was present on ZrO₂/Ti surface, with coating not affecting surface morphology compared to SLA/Ti. EDX, XPS, and XRD measurements confirmed the ZrO₂ coating on the roughened Ti. The amount of new bone was greater in ZrO₂/Ti (77.0 ± 7.2%) than in SLA/Ti (59.7 ± 5.8%) (<i>p</i> = 0.807). Collagen fibers oriented perpendicular to implant surface were observed more frequently in ZrO₂/Ti (67.3 ± 9.5%) than in SLA/Ti (18.8 ± 10.01%) (<i>p</i> < 0.001). The area of perpendicular collagen fibers was significantly larger in ZrO₂/Ti (53.1 ± 13.4%) than in SLA/Ti (16.8 ± 2.6%) <i>(p</i> = 0.002). Zirconia-coated implants maintained surface morphology and improved bone formation and fiber orientation in the gingiva compared to conventional titanium implants in short-term animal experiments.