bone graft swagatam by dept of oral and maxillofacial surgery

a presentation on bone graft

1. BONE GRAFT ​ Dept. of Oral and Maxillofacial Surgery Swagatam Roy Final year Roll no: 25 University Roll No:

2. OVERVIEW The bone healing is a complex and multifactorial process and takes longer time compared with soft-tissue healing. There are numerous steps involved in this healing process which can be influenced to redirect the growth accordingto the necessity. This allows many bone grafting technologies that have been used to regenerate bone, creating, perhaps, an array of options. Bone substitute materials can be classified based on the combination of their source of origin and mineral content. 2

3. INDEX Classification Bone Healing Osteoactive agents Application Risks Associated

4. Classification of Bone Grafts based on material groups: Allograft-based bone graft involves allograft bone, used alone or in combination with other materials (e.g., Grafton, OrthoBlast ). Factor-based bone graft are natural and recombinant growth factors, used alone or in combination with other materials such as transforming growth factor-beta (TGF-beta), platelet-derived growth factor (PDGF), fibroblast growth factors (FGF), and bone morphogeneic protein (BMP). Cell-based bone grafts use cells to generate new tissue alone or are added onto a support matrix, for example, mesenchymal stem cells. Ceramic-based bone graft substitutes include calcium phosphate, calcium sulphate, and bioglass used alone or in combination; for example, OsteoGraf, ProOsteon, OsteoSet. Polymer-based bone graft uses degradable and nondegradable polymers alone or in combination with other materials, for example, open porosity polylactic acid polymer.

5. Tissue Sources 5 Presentation title 20XX Autograft : Autologous or autogenous bone grafting involves utilizing bone obtained from same individual receiving the graft. Bone can be harvested from nonessential bones, such as from iliac crest, mandibular symphysis (chin area), and anterior mandibular ramus (coronoid process). When a block graft will be performed, autogeneous bone is the most preferred because there is less risk of graft rejection as the graft is originated from the patient′s body. It would be osteoinductive and osteogenic, as well as osteoconductive. Disadvantage of autologous grafts is that additional surgical site is required, another potential location for postoperative pain and complications Allograft : Allograft is derived from humans. The difference is that allograft is harvested from an individual other than the one receiving the graft. Allograft bone is taken from cadavers that have donated their bone so that it can be used for living people who are in need of it; it is typically sourced from a bone bank.

6. 6 Presentation title 20XX Xenograft : Xenogratfs are bone grafts from a species other than human, such as bovine and are used as a calcified matrix. Alloplastic : Alloplastic grafts may be made from hydroxyapatite, a naturally occurring mineral (main mineral component of bone), made from bioactive glass. Hydroxyapatite is a synthetic bone graft, which is the most used now due to its osteoconduction, hardness, and acceptability by bone. Some synthetic bone grafts are made of calcium carbonate, which start to decrease in usage because it is completely resorbable in short time and makes breaking of the bone easier. Finally used is the tricalcium phosphate in combination with hydroxyapatite and thus giving effect of both, osteoconduction and resorbability..

7. 7 Presentation title 20XX Ceramic-based : Majority of bone grafts available involve ceramics, either alone or in combination with another material (e.g., calcium sulfate, bioactive glass, and calcium phosphate). The use of ceramics, like calcium phosphates is calcium hydroxyapatite which is osteoconductive and osteointegrative ; and in some cases, osteoinductive. They require high temperatures for scaffold formation and have brittle properties. Polymer - based : This can be divided into natural polymers and synthetic polymers. Subclassified into degradable and nondegradable types. Polymer-based bone graft substitutes include the following: Healos is a natural polymer-based product, a polymer-ceramic composite consisting of collagen fibers coated with hydroxyapatite and indicated for spinal fusions. Cortoss is an injectable resin-based product with applications for load-bearing sites.

8. 8 Presentation title 20XX BONE HEALING Bone healing is a unique process similar to that of the embryonic bone formation. The healing of the bone graft depends upon the recipient site blood supply, oxygen tension and stability of bone segments. Healing of the bone graft may be by primary bone healing or by secondary bone healing(intermediate cartilaginous phase).

9. 9 Presentation title 20XX Primary Bone Healing : Primary bone healing of bone implies direct contact or a gap of less than1 mm between bone fragments. This healing process occurs by osteoclastsworking in groups to create a cutting cone. Following this cutting cone ofosteoclasts are osteoblasts secreting osteoid for future mineralisation

10. Secondary Bone Healing : Secondary bone healing occurs through the formation of a callus withinwhich osteoid is produced and mineralisation occurs. This type of bonehealing can be divided into the following three major phases Inflammatory phase ( haematoma formation) 2. Reparative phase (soft and hard callus formation) 3. Remodelling phase

11. Creeping substitution: It is a process by which the cortical bone graft healingoccurs , and it is similar to that of primary bone healing. Once thenonvascularised graft material is transferred to the defect, osteoclasts createvoids in the graft material that are filled with osteoid from osteoblasts. Thisosteoid then becomes mineralised , undergoes remodelling and maturation.Ideally , the grafted bone would be completely resorbed, and new bone wouldbe formed. The grafted bone remains as necrotic centres mixed with the newlyformed bone. Bone apposition: It is a process of bone healing that occurs in particulatedcortical or cancellous bone grafts. This apposition of bone is followed byresorption of the graft material. Ideally, there is complete resorption of thegraft material, which is replaced by mature bone. Because cancellous grafts donot have to first undergo resorption before apposition, they revascularisefaster than cortical block grafts. There is a much higher percentage of newlyformed bone and greater resorption of the graft material when particulategrafts are used.

12. Healing of Bone Graft :

13. Osteoactive Agents Transforming growth factor β Transforming growth factor beta (TGF-β) group proteins are grouped under osteopromotors, which have the ability for bone healing. The BMP family is found to include TGF-β. All stages of bone healing are found to involve TGF-β. Platelet-derived growth factors They are angiogenic in nature, help in the proliferation as well as chemotaxis for connective tissue cells including deposition of matrix which is essential for healing of bone. Platelet-rich plasma (PRP) It is coagulated platelet prepared from the person’s own blood by centrifugation process, followed by sequestering and concentrating the platelets, the PGDF and TGF-β for clinical use. Recombinant bone morphogenetic proteins. These are osteoinductive protein additives derived through recombinant tissue engineering technology. These consist of the osteoinductive component of several tissue engineering products that can induce de novo bone formation in the site these are implanted.

14. Preoperative clinical photo B. CT scan showing alveolar cleft C. BMP powder D. BMP powder mixed with sponge Surgical exposure of alveolar cleft Packing of the alveolar cleft Postoperative clinical photo H. Postoperative 3D Ct scan showing closure I. Regenerated new bone can be seen during implant placement .

15. APPLICATION : The most common use of bone grafting is in application of dental implants, in order to restore edentulous area of a missing tooth. In general, bone grafts are either used in block (such as from chin or ascending ramus area of lower jaw) or particulated , in order to be able to adapt it better to a defect. The grafted, vascularized fibulas have been used to restore skeletal integrity to long bones of limbs in which congenital bone defects exist and to replace segments of bone after trauma or malignant tumor invasion. The periosteum and nutrient artery are generally removed with piece of bone so that the graft will remain alive and grow when transplanted into new host site. Once the transplanted bone is secured into its new location, it generally restores blood supply to the bone on which it has been attached. Besides the main use of bone grafting in dental implants, this procedure is used to fuse joints to prevent movement, repair broken bones that have bone loss, and repair broken bone that has not yet healed.

16. NEED FOR BONE GRAFTING IN DENTISTRY

17. RISK FACTORS ASSOCIATED : Despite the high success rate of modern implantology and bone augmentation procedures, complications cannot be completely avoided. Thus, to avoid or detect them on time, potential risks and complications should be considered when making treatment decisions and conducting follow-ups. These possible complications have to be discussed with the patient before written surgical consent is obtained. In addition to the anatomical conditions that relate primarily to the bone and soft tissue conditions, patient selection plays a crucial role. Sufficient oral hygiene may be complicated by extensive prosthetic constructions and requires special patient motivation. Moreover, due to its high surface free energy, titanium seems to accumulate more plaque than the natural tooth.

18. CONCLUSION Hence b one grafts are used as a filler and scaffold to facilitate bone formation and promote wound healing. These grafts are bioresorbable and have no antigen-antibody reaction. These bone grafts act as a mineral reservoir which induces new bone formation and facilate successful implant restorations. 18 ~ Thank You