The Development of a Magnesium-Releasing and Long-Term Mechanically Stable Calcium Phosphate Bone Cement Possessing Osteogenic and Immunomodulation Effects for Promoting Bone Fracture Regeneration

Bone grafts are commonly used for the treatment of critical sized bone defects. Since the supply of autologous bone is insufficient, allogeneic bone grafts have been used most of the time. However, the poor osteogenic property of allogeneic bone grafts after pretreatment results in delayed union, non-union, or even occasional deformity. Calcium phosphate cement (CPC) is one of the most promising bone filling materials due to its good biocompatibility and similar chemical components as natural bone. However, clinical applications of CPC were hampered by limited osteogenic effects, undesired immune response which results in resorption, and poor mechanical stability in vivo. Magnesium (Mg) has been proven to trigger bone regeneration through modulating cell behaviors of mesenchymal stem cells and macrophages significantly. Unfortunately, the degradation raters of pure Mg and Mg oxide are extremely fast, resulting in early collapse of Mg contained CPC. In this study, we developed a novel magnesium contained calcium phosphate bone cement (Mg-CPC), possessing long-term mechanical stability and osteogenic effects through sustained release of Mg. Furthermore, in vitro studies showed that Mg-CPC had no cytotoxic effects on hBMMSCs and macrophage RAW 264.7, and could enhance the osteogenic differentiation as determined by alkaline phosphate (ALP) activity and calcium nodule staining, as well as suppress the inflammatory as determined by expression of anti-inflammatory cytokine IL-1RA. We also found that Mg-CPC promoted new bone formation and bone maturation in vivo. These results suggest that Mg-CPC should be a good substitute material for bone grafts in clinical use.

Research progress on the biological modifications of implant materials in 3D printed intervertebral fusion cages

Anterior spine decompression and reconstruction with bone grafts and fusion is a routine spinal surgery. The intervertebral fusion cage can maintain intervertebral height and provide a bone graft window. Titanium fusion cages are the most widely used metal material in spinal clinical applications. However, there is a certain incidence of complications in clinical follow-ups, such as pseudoarticulation formation and implant displacement due to nonfusion of bone grafts in the cage. With the deepening research on metal materials, the properties of these materials have been developed from being biologically inert to having biological activity and biological functionalization, promoting adhesion, cell differentiation, and bone fusion. In addition, 3D printing, thin-film, active biological material, and 4D bioprinting technology are also being used in the biofunctionalization and intelligent advanced manufacturing processes of implant devices in the spine. This review focuses on the biofunctionalization of implant materials in 3D printed intervertebral fusion cages. The surface modifications of implant materials in metal endoscopy, material biocompatibility, and bioactive functionalizationare summarized. Furthermore, the prospects and challenges of the biofunctionalization of implant materials in spinal surgery are discussed.

Types and tissue sources of bone grafts in dental implants

Using bone grafts has been described in the literature for multiple decades and has been applied within the different medical fields. Furthermore, in the field of dentistry, evidence shows that these approaches have been widely used for different purposes, including the management of craniofacial defects and dental implantology. However, it should be noted that many disadvantages have been reported for the different tissue sources of bone grafting in dental implants despite the wide acceptance of the outcomes and favorable prognosis with these materials. Therefore, many efforts were conducted to innovate further approaches with reduced disadvantages and favorable outcomes. Our present study discusses the types and tissue sources of bone grafts in the settings of dental implants. This can provide dentists with better information and enhanced knowledge levels about the tissue sources of dental implants, which should help them decide the most appropriate source with the least adverse events. Different tissue sources were reported in the literature, including materials that are no longer used for their disadvantages and associated complications. Among the proposed materials, biomimetics has been reported with favorable outcomes and reduced adverse events, and using combinations of these materials can furtherly enhance the prognosis. Further research is needed to innovate additional modalities that can overcome the currently reported limitations.

Economic impact of biomaterials for bone regeneration in Brazil during the pandemic

Implantable devices are therapeutic options for oral rehabilitation, with several presentations available in the dental consumption market. The consumption power of health products is a little explored in the literature, particularly in the face of financial crises. The aim of this study was to evaluate the economic impact of biomaterials for bone regeneration in Brazil during the pandemic. A quantitative study was carried out through online document analysis, with publicly accessible secondary data extracted from IBGE and websites for the sale of dental products. Data collection in the second quarter of 2020 and 2021 of absolute values ​​of products, official GDP data and population estimates allowed the generation of a biomaterial/income coefficient. The categories obtained from grafts and membranes were stratified by composition, origin and industry. Statistical analysis used the Shapiro-Wilk test to assess normality, the non-parametric Kruskall-Wallis test to compare the means of variables and the Wilcoxon test for paired samples of medians according to the two periods, considering significant differences if p <0.05. Of 97 products analyzed, a higher frequency of bone grafts than barrier membranes was observed, with an average growth of 18.5% in the price of biomaterials, below 28.7% of GDP in the same period. The highest prevalence of biomaterials was the ceramic composition for bone grafts and resorbable polymeric for membranes, from the xenogenous source and Brazilian industry. There was a chronological decrease in the biomaterial/income coefficient in most categories, with a drop in the general average from 4.67±4.40% to 4.30±3.96%, accompanied by an increase in the median, demonstrating a trend towards homogeneity of this coefficient in the comparison between years. The drop in the coefficient indicates a greater purchasing power of biomaterials by the potential consumer. Market knowledge can contribute for the decision making in clinical planning involving bone regeneration.