The aim was to investigate the osseointegration of a novel coating-plasma-sprayed nanostructured zirconia (NSZ) in dental implant. Nanostructured zirconia coating on non-thread titanium implant was prepared by plasma spraying, the implant surface morphology, surface roughness and wettability were measured. In vivo, nanostructured zirconia-coated implants were inserted in rabbit tibia and animals were respectively sacrificed at 2, 4, 8 and 12 weeks after implantation. The bond strength between implant and bone was measured by removal torque (RTQ) test. The osseointegration was observed by scanning electron microscopy (SEM), micro computed tomography (Micro CT) and histological analyses. Quantified parameters were calculated, including removal torque, Bone Volume to Tissue Volume (BV/TV), Trabecular Thickness (Tb. Th), Trabecular Number (Tb. N), Trabecular Separation/Spacing (Tb. Sp), and Bone-Implant contact (BIC) percentage. The statistical differences were detected by two-tail Mann-Whitney U test (SPSS 20.0). The surface roughness (1.58µm) and wettability (54.61°) of nanostructured zirconia coated implant was more suitable than those of titanium implant (0.598µm and 74.38°) for osseointegration and hierarchical surface morphology could be seen on zirconia coating. The histological analyses showed that zirconia coated implant induced earlier and more condensed bone formation than titanium implant at 2 and 4 weeks. Quantified parameters showed the significant differences between these two groups at early healing period, but the differences between these two groups decreased with the increase of healing period. All these results demonstrated that plasma sprayed zirconia coated implant induced better bone formation than titanium implant at early stage.
Keywords: Dental implant; Osseointegration; nanostructured zirconia coating; plasma spraying.