19Implant Tribune 19January 2014United Kingdom Edition opoietic illnesses. However, the bone marrow contains more than just haematopoietic stem cells (which give rise to red and white blood cells, as well as platelets, for example); it is also home to mesenchymal stem cells (which will become bone, muscle and fat tissues, for instance; Fig 3). Bone marrow harvesting is carried out under local anaes- thesia using an aspiration nee- dle through the iliac (pelvic) bone. Other than requiring a competent doctor to perform such a task, it is not regarded as an excessively invasive or com- plex procedure. It is also not associated with high levels of discomfort either intra or post- operatively (Figs 4a&b). Bone reconstruction is a challenge in dentistry (also in orthopaedics and oncology) be- cause rebuilding bony defects caused by trauma, infections, tumours or dental extractions requires bone grafting. The lack of bone in the jaws may impede the placement of dental implants, thus adversely affect- ing patients’ quality of life. In order to remedy bone scarcity, a bone graft is conventionally harvested from the chin region or the angle of the mandible. If the amount required is too large, bone from the skull, legs or pelvis may be used. Unlike the process for harvesting bone marrow, the process involved in obtaining larger bone grafts is often associated with high levels of discomfort and, occa- sionally, inevitable post-opera- tive sequelae (Figs 5a-e). The problems related to bone grafting have encour- aged the use of bone substitutes (synthetic materials and bone from human or bovine donors, for example). However, such materials show inferior results compared with autologous bone grafts (from the patient him/herself), since they lack autologous proteins. There- fore, in critical bony defects, that is, those requiring specific therapy to recover their origi- nal contour, a novel concept to avoid autologous grafting, in- volving the use of bone-sparing material combined with stem cells from the same patient, has been gaining ground as a more modern philosophy of treatment. Consequently, to the detriment of traditional bone grafting (with all its inherent problems), this novel method of combining stem cells with min- eralised materials uses a viable graft with cells from the patient him/herself without the need for surgical bone harvesting. ‘Bone reconstruc- tion is a challenge in dentistry (also in orthopaedics and oncology) because rebuilding bony defects caused by trauma, infections, tumours or dental extractions requires bone grafting’ page 20DTà Fig. 11d_Bone marrow combined with Ficoll (to aid cell separa- tion). Fig. 11d_Bone marrow combined with Ficoll (to aid cell separation).