Experimental Reconstruction of Critical Size Defects of Bone Tissue in the Maxillofacial Region When Using Modified Chitosan

Abstract

Rationale: The authors of the article propose a biomaterial design based on highly deacetylated chitosan, which replaces extensive bone defects. In the work, a biomaterial was used included freeze-dried implants based on highly deacetylated and high molecular weight chitosan, containing natural polysaccharides and inorganic nano-structural hydroxyapatite by intervention in white laboratory rats. Objectives: The goal is achieved due to the fact that a gel mass containing 2% chitosan ascorbate with a molecular weight of 100-700 kDa and a degree of deacetylation of 95-98% is introduced into large cavities. Sub-periosteal implantation of a chitosan structure into bone defects, CT analysis, morphometric analysis of histological sections of a bone defect allow us to reveal high efficiency in the early stages of bone reconstruction. Findings: When using modified chitosan to fill extensive bone defects in the jawbone in animals, the process of defect replacement occurs after 4-5 weeks with the formation of a full-fledged new bone tissue compared to control animals. Morphological analysis of the bone defect on the 7th day after the intervention showed signs of cancellous bone tissue formation, two weeks later - a pronounced increase in bone tissue volume (P <0.01). In the group with modified chitosan implantation, the amount of connective tissue formation was significantly lower (P <0.05) compared to the control group. CT analysis showed that after 6 weeks after the intervention, the closure of the defect by 70-80% is recorded, after 8 weeks - complete 100% closure of the defect without disturbing the morphology of the bone with a high degree of mineralization. Conclusions: Thus, modified chitosan is capable of eliminating bone defects of a critical size in the maxillofacial region, detecting early signs of angiogenesis and new bone formation, and serving as a promising material in reconstructive dentistry