Repair of Critical Size Bone Defects Using Synthetic Hydroxyapatite or Xenograft with or without the Bone Marrow Mononuclear Fraction: A Histomorphometric and Immunohistochemical Study in Rat Calvaria.

Ricardo Guimaraes Fischer,Mario José dos Santos Pereira,Jorge José de Carvalho,Igor da Silva Brum,Jorge Luís da Silva Pires,Lucio Frigo,Paulo Gonçalo Pinto dos Santos,Ana Lucia Rosa Nascimento

doi:10.3390/ma14112854

Abstract

Bone defects are a challenging clinical situation, and the development of hydroxyapatite-based biomaterials is a prolific research field that, in addition, can be joined by stem cells and growth factors in order to deal with the problem. This study compares the use of synthetic hydroxyapatite and xenograft, used pure or enriched with bone marrow mononuclear fraction for the regeneration of critical size bone defects in rat calvaria through histomorphometric (Masson’s staining) and immunohistochemical (anti-VEGF, anti-osteopontin) analysis. Forty young adult male rats were divided into five groups (n = 8). Animals were submitted to critical size bone defects (Ø = 8 mm) in the temporoparietal region. In the control group, there was no biomaterial placement in the critical bone defects; in group 1, it was filled with synthetic hydroxyapatite; in group 2, it was filled with xenograft; in group 3, it was filled with synthetic hydroxyapatite, enriched with bone marrow mononuclear fraction (BMMF), and in group 4 it was filled with xenograft, enriched with BMMF. After eight weeks, all groups were euthanized, and histological section images were captured and analyzed. Data analysis showed that in groups 1, 2, 3 and 4 (received biomaterials and biomaterials plus BMMF), a significant enhancement in new bone matrix formation was observed in relation to the control group. However, BMMF-enriched groups did not differ from hydroxyapatite-based biomaterials-only groups. Therefore, in this experimental model, BMMF did not enhance hydroxyapatite-based biomaterials’ potential to induce bone matrix and related mediators.

Highlights

The regeneration of bone defects represents one of the biggest challenges in implantology
The bone grafts commonly used in bone reconstruction surgeries are autogenous, allogeneic, xenogenous bones and alloplastic (synthetic hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP))
Only autogenous bone graft is endowed with osteogenic capacity and is considered the gold standard parameter for comparisons

Summary

Introduction

The regeneration of bone defects represents one of the biggest challenges in implantology. Alveolar bone defects can occur due to several factors, and the physiological bone resorption after extraction with the preservation of the dental alveolus, has been a topic highly addressed in the literature [1,2,3,4,5,6]. Tooth–facial trauma, periodontal disease, and endodontic treatment failure, in addition to bone/tooth-related cysts and tumors that affect the jaws may cause bone resorption [7,8,9]. The bone grafts commonly used in bone reconstruction surgeries are autogenous, allogeneic, xenogenous bones and alloplastic (synthetic hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP)). Only autogenous bone graft is endowed with osteogenic capacity and is considered the gold standard parameter for comparisons. The removal of an autogenous graft often carries a significant risk of morbidity [7]

Objectives

Methods

Results

Discussion

Conclusion