Biological Response to Recombinant Human Bone Morphogenetic Protein-2 on Bone-Implant Osseointegration in Ovariectomized Experimental Design:

Functionalised High-Performance Oxide Ceramics with Bone Morphogenic Protein 2 (BMP-2) Induced Ossification: An In Vivo Study

This study investigated the in vivo osseointegration potential of high-performance oxide ceramics (HPOCs) with peptide bone morphogenic protein 2 (BMP-2), comparing them with titanium implants. Histomorphometry was conducted around the distal, proximal, medial, and lateral sides of the implants to quantify the amount of mature and immature ossification within the bone interface. We hypothesised that HPOCs functionalised with BMP-2 promote ossification. HPOCs functionalised with BMP-2 were manufactured at the Department of Dental Materials Science and Biomaterial Research of the RWTH University Aachen, Germany. Histomorphometry was conducted by a professional pathologist in all samples. The region of interest (ROI) represented the percentage of the surrounding area of the implant. The percentages of ROI covered by osteoid implant contact (OIC) and mature bone−implant contact (BIC) were assessed. The surrounding presence of bone resorption, necrosis, and/or inflammation was quantitatively investigated. A total of 36 rabbits were used for the experiments. No bone resorption, necrosis, or inflammation was found in any sample. At the 12-week follow-up, the overall BIC was significantly increased (p < 0.0001). No improvement was evidenced in OIC (p = 0.6). At the 6-week follow-up, the overall OIC was greater in the BMP-2 compared to the titanium group (p = 0.002). The other endpoints of interest evidenced similarity between the two implants at various follow-up time points (p > 0.05). In conclusion, alumina HPOCs functionalised with peptide BMP-2 promote in vivo ossification in a similar fashion to titanium implants.

Reconstruction of a Large Posttraumatic Mandibular Defect Using Bone Tissue Engineering With Fresh-Frozen Humeral Allograft Seeded With Autologous Bone Marrow Aspirate and Vascularized With a Radial Forearm Flap

INTRODUCTION

Currently, vascularized autologous bone transplantation is considered the gold standard for large mandibular continuity defect reconstruction. Donor site morbidity is a major concern. Therefore, bone tissue engineering (BTE) seems to be the ideal solution. Fresh-frozen bone allograft is the closest material to autologous bone. The purpose of this clinical report is to show a new technique of large mandibular continuity defect reconstruction using a fresh-frozen humeral allograft seeded with autologous iliac bone marrow aspirate and vascularized with a radial forearm flap.

METHODS

A 33-year-old man presented with severe cranio-facial trauma resulting in several fractures of the facial skeleton including a comminuted mandibular fracture from left parasymphysis to left angle, which caused a large continuity defect.

RESULTS

Result at 6 months was aesthetically and functionally satisfactory with osseointegration of the bone graft.

DISCUSSION

The authors chose to use iliac bone marrow aspirate to seed the allograft scaffold since hematopoietic stem cells and mesenchymal stem cell are able to differentiate into osteoblasts, ease of harvest of the iliac crest and its low rate of morbidity. Contemporary biomaterials used for BTE are bioceramic but bone is still the better scaffold to engineer bone and only allografting avoids donor site morbidity. Vascularization is one of the main challenges of BTE; insertion of autologous vascular bundles from pedicle or free flaps is 1 solution. The authors chose the radial forearm flap since the pedicle is long and the authors did not need a great amount of soft tissue.