Titanium—hydroxyapatite porous structures for endosseous applications

Abstract

Materials for uncemented endosseous implants have to assure an as short as possible osseointegration time. Thus, a material with both surface bioactivity and a porous outer structure can become a preferred choice for this type of applications. This paper presents a class of titanium-base PM composites, reinforced with particulate hydroxyapatite. Raw materials were titanium powder, obtained through hydriding--milling--dehydriding, with the grain size of 63-100 microm, and sol-gel hydroxyapatite (HA) powder, produced by the reaction between Ca(NO3)2 x 4H2O and (NH4)2HPO4. Blends with 5 to 50% HA were prepared and pressed in a rigid die, producing single composition or gradual composition samples. The applied pressure was of 400, 500 or 600 MPa. Sintering was performed in vacuum, at 1160 ( composite function)C. All samples, although well sintered, displayed swelling during sintering, due to diffusion into the matrix. The increase in volume is more severe for higher amounts of HA in the green compacts and for higher applied compaction pressure. Compacts with a gradual increase of the HA content are recommended from the functional and mechanical point of view, but the increase should be slow, not to produce interlayer cracks. The outer surface shows interconnected pores, suitable for the ingrowth of vital new bone.

Ice-mould freeze casting of porous ceramic components

“…Hydroxyapatite as the basic mineral in mature bone is the most used material for bioactive fixation. 20 Once hydroxyapatite is implanted, it is bonded to the bone directly, enhancing the fixation in a shorter time and reducing healing time. 19 A synthetic scaffold for bone tissue engineering requires an inner structure with interconnecting pores.…”

“…21 As critical minimum pore size needed for the formation of a vital new bone 100 m are necessary. 20 Duan et al 22 produced biphasic porous hydroxyapatite/tricalcium phosphate ceramics with interconnecting pores. The porosity of the materials was 50-60%.…”

Immobilization of a carbon nanomaterial-based localized drug-release system using a bispecific material-binding peptide

“…These methods include the use of sintered metal beads, surface blasting, acid or alkaline treatment, anodization, and ion implantation. [7][8][9][10] Surface chemistry is a pivotal factor in the regulation of interactions between the biomaterial and cells/tissue. [11][12][13][14] In addition to these physical and chemical methods, modification using natural proteins, such as collagen, cell-adhesive molecules, or growth factors, has also been attempted.…”

Effect of HAP decomposition on the corrosion behavior of Ti–HAP biocomposites

“…[5,6] Ti-HAP biocomposites are considered as an alternative solution to combine the attractive properties of Ti and HAP. [3,[6][7][8] Several studies are available in the literature investigating these biocomposites in the form of homogenous composites, [3,6,7,[9][10][11][12][13][14][15][16][17] functionally graded materials (FGM), [18][19][20][21] and homogenous or graded composite coatings. [2,4,[22][23][24][25][26][27][28][29][30][31] Within these studies, powder metallurgy (P/M) was the most popular route to process bulk composites, whereas plasma spraying and sputtering were the most popular routes to process composite coatings.…”