In vivo osseointegration of Ti implants with a strontium-containing nanotubular coating

Abstract

Novel biomedical titanium (Ti) implants with high osteogenic ability for fast and good osseointegration under normal as well as osteoporotic conditions are urgently needed. Expanding on our previous in vitro results, we hypothesized that nanotubular, strontium-loaded (NT-Sr) structures on Ti implants would have favorable osteogenic effects and evaluated the in vivo osseointegration of these implants in rats. The structures with nanotubes of different diameters were fabricated by electrochemical anodization at 10 and 40 V, and the amounts of Sr loaded were adjusted by using two hydrothermal treatment times of 1 and 3 hours. Qualitative microcomputed tomography in two and three dimensions showed that the NT-Sr formed with an anodization voltage of 10 V and hydrothermal treatment time of 3 hours best supported bone growth in vivo. Histomorphometric examination of osseointegration also showed that more newly formed bone was found at its surface. The bone–implant contact percentage was highest (92.48%±0.76%) at 12 weeks. In conclusion, the NT-Sr formed with an anodization voltage of 10 V and hydrothermal treatment time of 3 hours showed excellent osteogenic properties, making it an attractive option for Ti surface modification with considerable clinical potential.

Effect of titanium implants with strontium incorporation on bone apposition in animal models: A systematic review and meta-analysis

“…Micro-computed tomography (micro-CT) evaluation was performed in seven of included studies 29 , 31 , 32 , 34 – 36 . In quantitative assessment, four studies 31 , 32 , 34 , 38 showed Sr-enhanced implants demonstrated stronger effect on all micro-CT parameters including bone volume per total volume (BV/TV), 3D bone distribution such as trabecular number (Tb.N), thickness (Tb.Th), and/or spacing (Tb.Sp) and/or the connective density (Conn.D) than control implants, while other three studies found no statistically significant changes in some parameters.…”

“…Nine of included studies 28 , 29 , 31 , 32 , 34 – 38 reported the results of biomechanical test including pull-out test or removal torque testing. All studies revealed a significant increase in implant fixation, with removal torque value, the maximal push-out force and/or the ultimate shear strength markedly raised compared to control groups.…”

Zn- or Cu-containing CaP-Based Coatings Formed by Micro-Arc Oxidation on Titanium and Ti-40Nb Alloy: Part II—Wettability and Biological Performance

“…Surface modification or functionalization is an efficient way to improve metal surface morphology, its chemical composition, and microstructure, which are important factors for implant biological performance. The studies [ 14 , 15 , 16 ] considered bioactive calcium phosphate (CaP) ceramic, similar in composition to bone tissue, which is applied on the Ti alloys to stimulate enhanced osseointegration and new bone formation. Micro-arc oxidation (MAO) also known as plasma electrolytic oxidation (PEO), is a novel method to prepare an in situ CaP coating with a wide range of physical and chemical properties on surface of valve metals and their alloys.…”

Functionalization of Ti-40Nb implant material with strontium by reactive sputtering

“…To minimize this risk, a locally administered release of strontium, for example by coating of surgical implants, would be highly beneficial [ 13 ]. Numerous studies found an increased biocompatibility and upregulation of osteogenesis related genes in vitro [ 14 – 16 ] and an effectively improved implant osseointegration in vivo , in bone-healthy [ 17 , 18 ] and recently in ovariectomized rats [ 19 ]. The spatial dispersion of the therapeutic agent Sr 2+ in rat bone with time in vivo was recently described by Rohnke et al [ 20 ].…”

“…Methods for preparation of strontium-releasing implant coatings involve hydro-thermal synthesis routes [ 15 – 17 ], Sr-substituted hydroxyapatite coating [ 21 , 22 ], NaOH treatment followed by strontium acetate treatment [ 14 ], electrolytic deposition techniques [ 23 , 24 ] and non-reactive magnetron sputtering [ 18 , 19 ]. For optimum medical performance of such coatings it is assumed, that ionic strontium needs to be released continuously over a period of several weeks while the pharmaceutical effect threshold is in the range of 0.10 mM and defined by the serum strontium level of postmenopausal osteoporosis patients that were treated with strontium ranelate [ 25 ].…”