In vivoimplantation of porous titanium alloy implants coated with magnesium-doped octacalcium phosphate and hydroxyapatite thin films using pulsed laser depostion

Abstract

The use of porous titanium-based implant materials for bone contact has been gaining ground in recent years. Selective laser melting (SLM) is a rapid prototyping method by which porous implants with highly defined external dimensions and internal architecture can be produced. The coating of porous implants produced by SLM with ceramic layers based on calcium phosphate (CaP) remains relatively unexplored, as does the doping of such coatings with magnesium (Mg) to promote bone formation. In this study, Mg-doped coatings of the CaP types octacalcium phosphate and hydroxyapatite (HA) were deposited on such porous implants using the pulsed laser deposition method. The coated implants were subsequently implanted in a rabbit femoral defect model for 6 months. Uncoated implants served as a reference material. Bone-implant contact and bone volume in the region of interest were evaluated by histopathological techniques using a tri-chromatographic Masson-Goldner staining method and by microcomputed tomography (µCT) analysis of the volume of interest in the vicinity of implants. Histopathological analysis revealed that all implant types integrated directly with surrounding bone with ingrowth of newly formed bone into the pores of the implants. Biocompatibility of all implant types was demonstrated by the absence of inflammatory infiltration by mononuclear cells (lymphocytes), neutrophils, and eosinophils. No osteoclastic or foreign body reaction was observed in the vicinity of the implants. µCT analysis revealed a significant increase in bone volume for implants coated with Mg-doped HA compared to uncoated implants.

Osteoblast Cell Response on the Ti6Al4V Alloy Heat-Treated

“…These findings can be explained by considering a weak adhesion and/or minor coverage of the osteoblast cells on the Ti6Al4V alloys (see below). Thus, it can be assumed that there is a poor interaction between the extracellular matrix excretion (mainly type I collagen) and the TiO 2 ; likely due to its adsorption (via oxygen) through oxygen vacancies, as has been reported in the literature [16,26,31,53]. Regarding the R extra values, a slight increase is seen at 1 day for Ti6Al4V as received, Ti6Al4V 800 and Ti6Al4V 1050 alloys, followed by its decrease after 7 days of immersion.…”

“…These include mechanical, chemical, physical, thermal and heat treatments [19,20], thermomechanical [21] and deep cryogenic treatments [22], coatings [23,24,25], alkali-plus-heat [26], ion implantation [27,28,29], plasma spray [30], laser metal deposition (LMD) [31], selective laser melting and laser remelting (SLM) [32]. Heat treatments, in particular, may cause changes in the microstructure of the material depending on both temperature and cooling velocity, as well as on aging and alloy elements.…”

X-ray computed tomography and additive manufacturing in medicine: a review

“…AM production and implantation of basic personalised implants based on XCT data are now commonplace, and reflecting this, a wide array of studies involving implantation have been published over the past year as the technology has become better understood [106][107][108][109][110][111][112][113][114][115][116][117][118][119]. Clinical usage of metallic implants produced by AM in particular is now becoming common, specifically in maxillofacial and orthopaedic applications, though a number of issues remain preventing further adoption.…”

Biodegradation Resistance and Bioactivity of Hydroxyapatite Enhanced Mg-Zn Composites via Selective Laser Melting

“…Selective laser melting (SLM) is a potential method to prepare homogeneous composites due to the rapid melting and solidifying process, which is able to limit the movement of the unmelted phase in the melt pool [15,16,17]. Wei et al [18] prepared stainless-steel/nano-hydroxyapatite composites by SLM and found that the decrease of solidification time could restrict the HA aggregation.…”