Analysis of a Pure Magnesium Membrane Degradation Process and Its Functionality When Used in a Guided Bone Regeneration Model in Beagle Dogs

Abstract

For the surgical technique of guided bone regeneration (GBR), the choice of available barrier membranes has until recently not included an option that is mechanically strong, durable, synthetic and resorbable. The most commonly used resorbable membranes are made from collagen, which are restricted in their mechanical strength. The purpose of this study is to evaluate the degradation and regeneration potential of a magnesium membrane compared to a collagen membrane. In eighteen beagle dogs, experimental bone defects were filled with bovine xenograft and covered with either a magnesium membrane or collagen membrane. The health status of the animals was regularly monitored and recorded. Following sacrifice, the hemimandibles were prepared for micro-CT (μ-CT) analysis. Complications during healing were observed in both groups, but ultimately, the regenerative outcome was similar between groups. The μ-CT parameters showed comparable results in both groups in terms of new bone formation at all four time points. In addition, the μ-CT analysis showed that the greatest degradation of the magnesium membranes occurred between 1 and 8 weeks and continued until week 16. The proportion of new bone within the defect site was similar for both treatment groups, indicating the potential for the magnesium membrane to be used as a viable alternative to collagen membranes. Overall, the new magnesium membrane is a functional and safe membrane for the treatment of defects according to the principles of GBR.

Biodegradation of a Magnesium Alloy Fixation Screw Used in a Guided Bone Regeneration Model in Beagle Dogs

“…Other studies have reported the presence of void spaces around magnesium implants that resolve themselves after the metallic magnesium has degraded, without negatively affecting new bone formation [23][24][25][26]28]. This was also shown in our study, where despite the early formation of void spaces at the 1-week timepoint, the void space continually reduced in volume, whilst equivalent levels of new bone formation were measured for both the magnesium and titanium fixation screw groups at every timepoint.…”

“…The presence of hydrogen gas has also previously been linked to inflammatory reactions [28,33,34]. This could have caused the swelling reported at later timepoints for eight of the magnesium-treated sites, which mostly occurred between 4 and 8 weeks postimplantation.…”

“…In addition to the creation of magnesium salts, as the metallic structure degrades it releases hydrogen gas, which can lead to the formation of gas cavities around the implant. However, previous studies using magnesium alloy screws in orthopedics for bone fixation have demonstrated that if gas cavities are present, they will spontaneously resolve once the metallic phase has degraded and will not have a negative effect on bone formation [21][22][23][24][25][26][27][28]. In this current study, we investigate the functionality of the newly developed magnesium fixation screw in a canine mandibular defect model.…”

“…Prior to histological processing, the defects in the explanted hemimandibles were scanned using a Nikon XTH 225 ST Micro-CT scanner [28]. µCT data were then used to reconstruct a 3D image of each defect containing 4 screws (where possible), which consisted of 16-bit volume data at 10 µm isotropic voxel size.…”

The Use of Collagen-Based Materials in Bone Tissue Engineering

“…Other methods to overcome these issues are the use of new manufacturing approaches, such as electrophoretic deposition, electrospinning, and 3D printing, to improve the mechanical and biological properties of collagen membranes [ 117 , 118 ]. Recently, another potential material alternative, based on a resorbable magnesium grid for volume stability, combined with a collagen membrane or a pure magnesium membrane, have been developed for GBR procedures [ 119 , 120 ].…”