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- Halldin, Anders, et al.
(författare)
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The effect of static bone strain on implant stability of bone remodelling
- 2011
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Ingår i: Bone. - : Elsevier. - 8756-3282 .- 1873-2763. ; 49:4, s. 783-789
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Tidskriftsartikel (refereegranskat)abstract
- Bone remodeling is a process involving both dynamic and static bone strain. Although there exist numerous studies on the effect of dynamic strain on implant stability and bone remodeling, the effect of static strain has yet to be clarified. Hence, for this purpose, the effect of static bone strain on implant stability and bone remodeling was investigated in rabbits. Based on Finite Element (FE) simulation two different test implants, with a diametrical increase of 0.15 mm (group A) and 0.05 mm (group B) creating static strains in the bone of 0.045 and 0.015 respectively, were inserted in the femur (group A) and the proximal tibia metaphysis (groups A and B respectively) of 14 rabbits to observe the biological response. Both groups were compared to control implants, with no diametrical increase (group C), which were placed in the opposite leg. At the time of surgery, the insertion torque (ITQ) was measured to represent the initial stability. The rabbits were euthanized after 24 days and the removal torque (RTQ) was measured to analyze the effect on implant stability and bone remodeling. The mean ITQ value was significantly higher for both groups A and B compared to group C regardless of the bone type. The RTQ value was significantly higher in tibia for groups A and B compared to group C while group A placed in femur presented no significant difference compared to group C. The results suggest that increased static strain in the bone not only creates higher implant stability at the time of insertion, but also generates increased implant stability throughout the observation period.
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| 2. |
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| 3. |
- Peruzzi, Niccolò, et al.
(författare)
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Multimodal ex vivo methods reveal that Gd-rich corrosion byproducts remain at the implant site of biodegradable Mg-Gd screws
- 2021
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Ingår i: Acta Biomaterialia. - : Elsevier. - 1742-7061 .- 1878-7568. ; 136, s. 582-591
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Tidskriftsartikel (refereegranskat)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.
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