۱- Introduction

۲- Materials and methods

۳- Results

۴- Discussion

References

Abstract

Objective. The aim of this study is to investigate bone healing ability of niobium-containing bioactive glasses in rat femur model with quantitative and qualitative measurements through x-ray computed microtomography.
Methods. Niobium-containing bioactive powders and scaffolds were produced by sol–gel route (BAGNb). Glasses without niobium addition were produced as well (BAG). Five groups were used: BAGNb powders, BAG powders, BAGNb scaffolds, BAG scaffolds and, as a control group, autogenous bone was used. Materials were implanted in the femur of male rats (Wistar Lineage n= 10) and the healing was observed after 15, 30 and 60 days. After the post-operative times, samples were scanned by X-ray microcomputed tomography where morphometric measurements and the mineral density were assessed in image software.
Results. No postoperative complications were observed after surgery. BAGNb glasses presented higher mineral deposition, which was observed in the relative volume of bone and the mineral density when compared BAG groups. In these parameters, no statistical difference was found between BAGNb and autogenous bone. The BAGNb powders presented a higher amount of mineralized tissue when compared to BAGNb scaffolds. The analysis oftrabecular structure showed lower trabecular formation in synthetic materials when compared to autogenous bone.
Significance. Niobium-containing bioactive glasses promoted bone formation comparable to that of the autogenous bone without compromising the quality of the formed bone.

Introduction

Bioactive glasses are a class of synthetic materials that may be used in bone regeneration applications in dentistry [1,2]. The osteoinductive and osteoconductive abilities [3] of these glasses are related to their ion release that promotes bone formation by way of two mechanisms, specifically 1) the formation of a carbonated hydroxyapatite layer in the surfaces of the particles [4] and 2) the upregulation of cell activity to stimulate the deposition of bone tissue [5]. Improvements in glass composition and structure may contribute to an improved release of bioactive ions and increased bone formation. The enhancement of bioactive glass composition and production may improve bone regeneration capacity. Niobium has been investigated as biomaterial to be used [6–۹] due to its ability to promote mineral deposition [6,7,10,11]. The development of sol–gel-derived, niobium-containing bioactive glasses powders and scaffolds was previously shown [7] and increased mineralization ability was observed for niobium-containing grafts in vitro. Several approaches are used to promote the reestablishment of bone tissue for prosthetic rehabilitation, while autogenous bone remains the gold standard graft for maxillae and mandible reconstructions [12–۱۵]. Synthetic bone substitutes have been used as alternatives that have ensured reduced patient morbidity [13] and comparable bone formation [14]. The placement of dental implants in edentulous patients is additionally related to improved health parameters and an increased quality of life, but may be limited in terms of efficacy by the absence of adequate quality and quantity of bone [15]. The aim of this study was to investigate the bone healing ability of niobium-containing bioactive glasses in a rat femur model according to quantitative and qualitative measurements obtained through X-ray computed microtomography. The working hypothesis is thatthe addition of niobium increased the bone regeneration ability promoted by sol-gel derived bioactive glasses.