Biocompatibility and Immune Response of a Newly Developed Volume-Stable Magnesium-Based Barrier Membrane in Combination with a PVD Coating for Guided Bone Regeneration (GBR)

Abstract

To date, there are no bioresorbable alternatives to non-resorbable and volume-stable membranes in the field of dentistry for guided bone or tissue regeneration (GBR/GTR). Even magnesium (Mg) has been shown to constitute a favorable biomaterial for the development of stabilizing structures. However, it has been described that it is necessary to prevent premature degradation to ensure both the functionality and the biocompatibility of such Mg implants. Different coating strategies have already been developed, but most of them did not provide the desired functionality. The present study analyses a new approach based on ion implantation (II) with PVD coating for the passivation of a newly developed Mg membrane for GBR/GTR procedures. To demonstrate comprehensive biocompatibility and successful passivation of the Mg membranes, untreated Mg (MG) and coated Mg (MG-Co) were investigated in vitro and in vivo. Thereby a collagen membrane with an already shown biocompatibility was used as control material. All investigations were performed according to EN ISO 10993 regulations. The in vitro results showed that both the untreated and PVD-coated membranes were not cytocompatible. However, both membrane types fulfilled the requirements for in vivo biocompatibility. Interestingly, the PVD coating did not have an influence on the gas cavity formation compared to the uncoated membrane, but it induced lower numbers of anti-inflammatory macrophages in comparison to the pure Mg membrane and the collagen membrane. In contrast, the pure Mg membrane provoked an immune response that was fully comparable to the collagen membrane. Altogether, this study shows that pure magnesium membranes represent a promising alternative compared to the nonresorbable volume-stable materials for GBR/GTR therapy.

Biocompatibility Analyses of HF-Passivated Magnesium Screws for Guided Bone Regeneration (GBR)

“…GBR therapy is based on the use of barrier membranes to enable regeneration of lost bone tissue in dentistry, maxillofacial surgery and other surgical disciplines [9,15,48,49,51,52]. To stabilize these membranes and hence the underlying bone substitute during the healing process, the use of fixation screws has been proven to be an effective approach [53][54][55].…”

“…Nonresorbable fixation systems made of titanium (Ti) are the most widely used applications for this purpose, due to their good mechanical properties and biocompatibility, but are also associated with typical disadvantages, similar to delayed osteointegration and microbial colonization [56,57]. An additional concern is the reported accumulation of material particles around Ti and ceramic implants [58,59] However, the main disadvantage for nonresorbable fixation screws is the requirement for their subsequent surgical removal and the resulting risks for the patient [9,49,56,57,60]. Bioresorbable screws, made from polymers such as polylactide and polyglycolide and their copolymers are also available [22,23,61,62].…”

“…GBR is based on the principle of excluding fast proliferating cells, such as epithelium cells from the augmentation site, while promoting a micromilieu favorable for jawbone regeneration by osteoblasts [6,7]. The central element of this concept is the barrier membrane, which enables the seclusion of the augmentation site [8][9][10]. A variety of resorbable and non-resorbable membranes are available, each coming with different properties determined by their chemical composition or origin [2,[11][12][13][14].…”

“…In the last decades, the use of resorbable membranes, most often collagen based, have been established in dentistry, as their application does not require a second surgical intervention for their removal. The progression from non-resorbable to resorbable membranes shows that degradable materials in surgery and specifically in dental implantology are becoming the materials of choice for most clinicians, and a positive trend toward completely bioresorbable material systems [9,[15][16][17][18].…”

In VitroandEx VivoAnalysis of Collagen Foams for Soft and Hard Tissue Regeneration

“…For this purpose, pore size, density and surface structure of the foams were examined and described ex vivo using a dynamic foam analyzer (DFA) and cryo-SEM. In addition, in vitro cytocompatibility studies were carried out in accordance with ISO 10993-5/-12, as already described in previous work (24,39,40).…”