الفهرس 
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Abstract
Summary
Distraction osteogenesis (DO) is a technique used in oral and maxillofacial field to reconstruct missing bony segments without the need of grafting to avoid donor site morbidity. DO was first mentioned by Hippocrates. Codivilla and Ilizarov introduced it to medical literature as a surgical technique. DO was first used in the oral and maxillofacial region in 1992 by McCarthy et al. since then, the surgical and technological advances made in the field of DO provided oral and maxillofacial surgeons with a safe and predictable method to treat selected deformities of the oral and facial skeleton.
However, maxillofacial DO has a lot of draw backs. DO is a long procedure in which patients are at risk of complications during this procedure such as pain, re-fracture, infection, nonunion or no compliance as well as suffering of psychological depression and economical burden. Rapid rate DO was proposed to decrease the distraction time to avoid consequences of long procedure. There are two major treatment modalities for hypoplastic mandibles; early approaches (during growth) or a late approach (after puberty).
Mesenchymal stem cells present new hope in the science of regenerative medicine. Harvesting adult stem cells reduced the ethical problem associated with mesenchymal stem cell application; since it provides stem cells with no embryonic sacrifice. The current issue associated with mesenchymal stem cell harvesting is how to harvest with the least donor site morbidity and minimal invasive procedure.
The idea of the current study is to provide mesenchymal stem cells which act as mother cells capable of differentiating into osteoblast to form new bone, endothelium cells to give new blood capillaries, immune cell as macrophages to provide immunity and may help in forming better soft tissue drape for better healing. This idea was used in management of healing fractures in orthopedic studies. Patterson et al. in (2008) defined the term connective tissue progenitors as the heterogeneous populations of stem and progenitor cells that are found in native tissue which can differentiate into one or more connective tissue phenotypes.
In a previous study mesenchymal stem cells were delivered either by the addition of bone marrow directly to the healing site to improve bone healing or by centrifuging the bone marrow to get a concentrate rich mesenchymal stem cells to get better results and adding the concentrate to the healing site and this idea was conducted in multiple researches.
Both distraction osteogenesis and mesenchymal stem cell application carries big hopes for regenerative medicine. The combination of both may overcome the current draw backs associated with distraction osteogenesis.
The aim of the study was to evaluate the effect of Bone Marrow Aspirate Concentrate (BMAC) on bone regenerate during rapid mandibular distraction osteogenesis.
Prospective case-control trial was conducted on patients requiring mandibular distraction osteogenesis. The research was reviewed by the ethical committee of Faculty of Dentistry Ain Shams University. Patients were randomly allocated into one of the two groups. group A (control) (6 mandibles): control group in which distraction took place at a rate of 1.5 mm /day till planned length was obtained and only saline was injected in defect; based on the assumption that it have no effect on bone healing. group B (6 mandibles): study group in which distraction took place at rate of 1.5 mm /day till planned length was obtained. Distracted bone was enhanced by injection of Bone Marrow Aspirate Concentrate (BMAC).
In order to evaluate the effect of BMAC on bone maturation and possibility of early removal of the distractor; which was not feasible in the clinical study due to the ethical concerns. Mechanical three point bending was applied on distracted mandible after 30 days following distraction to evaluate bone healing and mechanical strength of distracted bone. In addition to histological and radiographic evaluation.
The results were divided into clinical and experimental results. The clinical results first showed that the protocol of distraction used improved the cosmetics significantly these results needed to be mentioned even if it has no relation to study aim. The BMAC improve the radiographic bone density and mechanical properties but the improvement was of no statistical significance. The BMAC only statistically significant improvement was in the histological evaluation in the experimental trial.
Consequently, the current study recommend further examination to evaluate the effect of MSCs in form of BMAC on distracted bone because of non-significant and non-correlated improvement in the physical properties (biomechanical strength) which have direct effect on clinical outcome compared to histological nature which has no clinical outcome.
Until new observation is published in literature the current study still recommends augmentation after distraction osteogenesis to improve volume defects. The article also recommend classic consolidation time till BMACs proves in future article it effect on fastening the bone healing