Influence of a magnesium‐fluoride coating of magnesium‐based implants (MgCa0.8) on degradation in a rabbit model

Abstract

MgCa0.8 cylinders (2.5 x 25 mm(2)) were coated with a magnesium-fluoride layer and implanted in the marrow cavities of both tibiae of 10 New Zealand White rabbits. The implantation duration was 3 and 6 months. The implants were clinically well tolerated. Micro-computed tomography revealed a new bone formation at the edges of the implants as well as an endosteal and periosteal remodeling. Using EDX-analysis, a calcium and phosphorus rich degradation layer could be found on the implant surface. It was covered by an incomplete layer containing fluoride. The analysis by weight before implantation and after 3 and 6 months, respectively, showed a slight decrease in volume in comparison to uncoated implants. When compared with uncoated implants, the mechanical properties of the coated implants exhibited a reduction in strength after 3 months. After 6 months, the strength of the coated implants was higher than that of uncoated cylinders.

Magnesium Alloys as Promising Degradable Implant Materials in Orthopaedic Research

“…A higher bone volume per tissue volume around degrading magnesium implants and a more mature bone structure in comparison to a control group was described in other studies as well (Witte et al, 2007b;Xu et al, 2009). Besides the biocompatibility, the tensile strength is regarded to be the critical mechanical characteristic of an implant that is supposed to be used as implant material in weight bearing bones and to stabilize bone fragments (McKibbin, 1978), while its ductility is of less importance (Hort et al, 2009, Krause et al 2010). As it is known and even found in the described studies, magnesium alloys have a tendency for pitting corrosion (Song et al, 2005).…”

Recent Advances in Biodegradable Metals for Medical Sutures: A Critical Review

“…[ 199,[203][204][205] While magnesium fl uoride positively impacts the corrosion performance of magnesium and its alloys, it also increases the mouse osteoblast-like (MC3T3-E1) and human osteosarcoma (MG63) cells, along with bone tissue compatibility, which has been shown using in vivo and in vitro tests. [ 199,[206][207][208] The MgF 2 coating releases fl uorine as part of the degradation process, which is considered to be non-toxic due to the natural existence of fl uorine in the human body. [ 199,205 ] Unfortunately, MgF 2 is a comparatively brittle coating [ 203 ] and is not a valid option for sutures, which undergo manifold deformations during stitching and wound closing.…”

“…While Mg alloys may possess adequate mechanical properties, this does not automatically translate into an adequate corrosion rate. [ 146,199 ] The accelerated corrosion behavior of Mg and its alloys, in accordance with an early loss of integrity and a high hydrogen evolution rate, has been proven in various in vivo studies. [ 21,35,[200][201][202] A lower and upper limit for the corrosion rate of degradable suture implants is currently not defi ned.…”

“…[ 199,[206][207][208] The MgF 2 coating releases fl uorine as part of the degradation process, which is considered to be non-toxic due to the natural existence of fl uorine in the human body. [ 199,205 ] Unfortunately, MgF 2 is a comparatively brittle coating [ 203 ] and is not a valid option for sutures, which undergo manifold deformations during stitching and wound closing.…”

Influence of The KF Concentration on The Coating Process And Properties of Potentiostatic Deposited Fluoride Conversion Film on AZ31 Mg Alloy

“…Consequently, in order to decrease their degradation rate and thus accumulation of H 2 to match the healing rate of damaged bones, fluoride conversion film (FCF) has been developed, attributed to the harmlessness of the fluorine ions releasing into the organism [8] , its good biotissue compatibility [9][10][11][12] , excellent cell adhesion [13][14] , and its characteristics to accelerate the osseointegration rate [15] , enhance bone healing [16] and prevent the biofilm formation [17][18][19] . The original method to fabricate FCF on Mg substrate was immersion of Mg substrate in 40% or 48% hydrofluoric acid, HF [19][20][21][22][23][24][25] , however, the high toxicity…”