Nano hydroxyapatite structures influence early bone formation

Abstract

In a study model that aims to evaluate the effect of nanotopography on bone formation, micrometer structures known to alter bone formation, should be removed. Electropolished titanium implants were prepared to obtain a surface topography in the absence of micro structures, thereafter the implants were divided in two groups. The test group was modified with nanosize hydroxyapatite particles; the other group was left uncoated and served as control for the experiment. Topographical evaluation demonstrated increased nanoroughness parameters for the nano-HA implant and higher surface porosity compared to the control implant. The detected features had increased size and diameter equivalent to the nano-HA crystals present in the solution and the relative frequency of the feature size and diameter was very similar. Furthermore, feature density per microm(2) showed a decrease of 13.5% on the nano-HA implant. Chemical characterization revealed calcium and phosphorous ions on the modified implants, whereas the control implants consisted of pure titanium oxide. Histological evaluation demonstrated significantly increased bone formation to the coated (p < 0.05) compared to uncoated implants after 4 weeks of healing. These findings indicate for the first time that early bone formation is dependent on the nanosize hydroxyapatite features, but we are unaware if we see an isolated effect of the chemistry or of the nanotopography or a combination of both.

Fortifying the Bone-Implant Interface Part 2: An In Vivo Evaluation of 3D-Printed and TPS-Coated Triangular Implants

“…These AM implants likewise demonstrated substantial bone ongrowth and ingrowth to their porous surfaces, with additional bone through growth in the cores. Although similar HA coatings have previously demonstrated a beneficial effect on non-porous titanium surfaces or inert structures, such as PEEK, 26,27 the current study showed that the dip, spin, heat treated nanocrystalline HA coating did not further enhance results compared to uncoated AM implants. The addition of autograft, on the other hand, resulted in significantly increased bone ingrowth and through growth within the AM implant, potentially further promoting osteointegration.…”

“…For AM+HA implants, a ~20nm layer of HA was applied to implant surfaces using a dip-coating precipitate technique as previously described. 26,27 AM+Auto implants are described in the Animal Model section below. All implants were gamma-sterilized prior to use.…”

In vitro osteoinduction of human mesenchymal stem cells in biomimetic surface modified titanium alloy implants

“…Such modifications of the atomic composition of the surface have led to significant improvements in the cell response on the surface material both in vitro and in vivo [10][11][12][13] . Impregnation or coating with hydroxyapatite 14,15) or calcium phosphate 16,17) have been proposed as biomimetic approaches. However, despite the success achieved through surface chemistry modifications in the early host-implant integration, there is a general consensus that the modulation of surface texturing is also an important and desirable variable, regardless of the surface chemistry approach followed in endosseous implants 18,19) .…”

Value of color Doppler ultrasonography and radiography for the assessment of the cancellous bone scaffold coated with nano-hydroxyapatite in repair of radial bone in rabbit

“…Hydroxyapatite (HA) and other calcium phosphate materials have been indicated in cases in which the optimal surgical fit is not achievable during surgery, and the HA surface properties may enhance bone filling of the defect area 6 . The biological properties of the synthetic hydroxyapatite are well documented in literature, and it has been used for correcting bone defects in human beings and in other species 7 .…”