| 1. |
- Johansson, Pär, et al.
(author)
-
Biomechanical, histological, and computed X-ray tomographic analyses of hydroxyapatite coated PEEK implants in an extended healing model in rabbit
- 2018
-
In: Journal of Biomedical Materials Research Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 106:5, s. 1440-1447
-
Journal article (peer-reviewed)abstract
- A nanosized hydroxyapatite (HA) modification on polyetheretherketone (PEEK) using a novel spin coating technique was investigated in a rabbit model. Spin coating technique creates a 20-40 nm thick layer of nanosized HA particles with similar shape, size, and crystallinity as human bone. Some implants were designed with a perforating hole in the apical region to mimic a fusion chamber of a spinal implant. The coating nano-structures were assessed using a scanning electron microscope. The in vivo response to HA-PEEK was compared to untreated PEEK with respect to removal torque, histomorphometry, and computed microtomography. The HA-coated and pure PEEK implants were inserted in the tibia and femur bone according to simple randomization. The rabbits were sacrificed 20 weeks after implantation. Removal torque analysis showed significantly higher values for HA-PEEK. Qualitative histological evaluation revealed an intimate contact between PEEK and the bone at the threads and perforated hole. Histomorphometric assessment showed higher bone-implant and bone area values for HA-PEEK but without statistical significance. The effect of the HA coating showed most prominent effect in the removal torque which may be correlated to an alteration in the bone quality around the HA-PEEK implants. (c) 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1440-1447, 2018.
|
|
| 2. |
- Kruger, D., et al.
(author)
-
High-resolution ex vivo analysis of the degradation and osseointegration of Mg-xGd implant screws in 3D
- 2022
-
In: Bioactive Materials. - : Elsevier BV. - 2452-199X. ; 13, s. 37-52
-
Journal article (peer-reviewed)abstract
- Biodegradable magnesium (Mg) alloys can revolutionize osteosynthesis, because they have mechanical properties similar to those of the bone, and degrade over time, avoiding the need of removal surgery. However, they are not yet routinely applied because their degradation behavior is not fully understood. In this study we have investigated and quantified the degradation and osseointegration behavior of two biodegradable Mg alloys based on gadolinium (Gd) at high resolution. Mg-5Gd and Mg-10Gd screws were inserted in rat tibia for 4, 8 and 12 weeks. Afterward, the degradation rate and degradation homogeneity, as well as bone-to-implant interface, were studied with synchrotron radiation micro computed tomography and histology. Titanium (Ti) and polyether ether ketone (PEEK) were used as controls material to evaluate osseointegration. Our results showed that Mg-5Gd degraded faster and less homogeneously than Mg-10Gd. Both alloys gradually form a stable degradation layer at the interface and were surrounded by new bone tissue. The results were correlated to in vitro data obtained from the same material and shape. The average bone-to-implant contact of the Mg-xGd implants was comparable to that of Ti and higher than for PEEK. The results suggest that both Mg-xGd alloys are suitable as materials for bone implants.
|
|
| 3. |
- Peruzzi, Niccolò, et al.
(author)
-
Multimodal ex vivo methods reveal that Gd-rich corrosion byproducts remain at the implant site of biodegradable Mg-Gd screws
- 2021
-
In: Acta Biomaterialia. - : Elsevier. - 1742-7061 .- 1878-7568. ; 136, s. 582-591
-
Journal article (peer-reviewed)abstract
- Extensive research is being conducted on magnesium (Mg) alloys for bone implant manufacturing, due to their biocompatibility, biodegradability and mechanical properties. Gadolinium (Gd) is among the most promising alloying elements for property control in Mg alloy implants; however, its toxicity is controversial. Investigating Gd behavior during implant corrosion is thus of utmost importance. In this study, we analyzed the degradation byproducts at the implant site of biodegradable Mg-5Gd and Mg-10Gd implants after 12 weeks healing time, using a combination of different imaging techniques: histology, energy-dispersive x-ray spectroscopy (EDX), x-ray microcomputed tomography (µCT) and neutron µCT. The main finding has been that, at the healing time in exam, the corrosion appears to have involved only the Mg component, which has been substituted by calcium and phosphorus, while the Gd remains localized at the implant site. This was observed in 2D by means of EDX maps and extended to 3D with a novel application of neutron tomography. X-ray fluorescence analysis of the main excretory organs also did not reveal any measurable accumulation of Gd, further reinforcing the conclusion that very limited or no removal at all of Gd-alloy happened during degradation.
|
|
