The influence of nano hydroxyapatite coating on osseointegration after extended healing periods

Objective. Studies observing early wound healing periods around dental implants demon-strate an implants ability to enhance osseointegration, the bone-implant interactions for extended healing periods though have not been thoroughly studied. Methods. Twenty threaded titanium alloy (Ti6Al4V, Grade 5) implants were inserted bilaterally, half prepared to impart stable hydroxyapatite nanoparticles onto a sand blasted and acid etched surface (HA) and half with a non-coated control surface with only heat treatment (HT), into eighteen rabbit femurs. At 12 weeks, the bone-implant blocks were retrieved for micro computed tomography (mu CT), histologic processing and histomorphometric evaluation. Results. The bone-to-implant contact for the entire threaded portion of the implant revealed 57.1% (21.0) for the HT group and 38.8% (17.7) for the HA group with a total bone area within the threads 72.5% (13.9) (HT) and 59.7% (12.5) (HA). The 3D reconstructed mu CT image corresponded to the histomorphometric results. Significance. It is suggested that multiple factors such as the change in topography and chemistry may have influenced the outcomes.