 Hello everyone welcome back to another session in dentistry and more today's topic in pedontics is bone grafts. So bone grafts are nothing but materials which is used for replacement or augmentation of the bone. So it is a procedure used to replace or restore the missing bone or gum tissues. So this session is about the biologic mechanisms involved in grafting and various types of graft. So let's get into the details of bone grafts. So grafting is nothing but implanting a healthy tissue from the donor side to the recipient side. So here the defect is present so we keep a healthy tissue to the new recipient side so that it is restored repaired and regenerated. So what are the rationality of this process? Because this process will enhance the regenerative capacity of the bone and it will achieve new attachment apparatus. Okay so these are the rationality of this grafting and basically we have three biologic mechanism which is happening in grafting. The first one is osteoconduction then osteoinduction and osteogenesis. So this is the process how the new bone forms at the recipient side. So you can see all is having osteo that is a bone. So one bone formation via conduction, second via induction and this is a natural process genesis. Okay so what is exactly osteoconduction? So osteoconduction okay it is a formation of bone by osteoblasts from the margins of the defect on the bone graft material. Okay so this is a graft material okay so this is a graft material we are implanted this is a recipient side okay this is a recipient side and this is a graft material we just remove this. So this is from donor side we implanted a graft here. So osteoconduction means formation of bone by osteoblasts from the margins of the defects on the bone graft material. Okay so this is a margin okay this is a margin okay so there will be osteoblasts here. So it serves as scaffold for bone growth it does not inhibit nor induce bone formation okay no inhibition no induction. So what happens is it facilitates bone formation by bridging the gap okay so bridging the gap. So there is a gap here that is between defect and the new graft which is implanted. So there is no inhibition there is no induction just facilitating the scaffold just facilitating to close the gap between the newly kept graft and the defect margins. So it simply allows the normal formation of bone by osteoblasts into the graft defect along the surface of graft material. So this is a surface of graft material. So along the surface of graft material there will be bone formation and bridging the gap. So this is osteoconduction okay. So whereas osteo induction is it involves new bone formation via stimulation of osteoprogenators from the defect okay that is means from the vasculature then it differentiates into osteoblast and begin forming of new bone. So here the bone formation is induced okay it is induced with the help of some inactive material such as bone morphogenic proteins okay. So these induction of bone forming process by cells that would otherwise remain inactive. So these bone morphogenic proteins induce bone formation in osteoconduction there was no induction it was just facilitating here the induction that is the osteoprogenators are stimulated via the new defect that is from vasculature to differentiate into osteoblast with the help of bone morphogenic proteins. Whereas osteogenesis is the normal process of bone formation it occurs when leaving osteoblast a part of the bone graft. So there is already present osteoblast within the graft so when there is adequate blood supply and cellular viability these transplanted osteoblast from the new centers of ossification within the graft starts forming bone and it creates the new bone okay. So because this osteoblast already exist and added as a part of the bone graft from ossification centers which contributes to the total capacity for bone formation. So these are the basic difference in osteo induction it is induced by BMP it act as a scaffold and close the gap this is the cells are present within the that is osteoblast is present within the graft here the inert material like BMP induce bone formation that is a difference between these three mechanism okay. And now let's move on to the types of graft so we have the autographed that is intraoral and extraoral type another one is yellow graft which is taken from the same species xenograft from the different species alloplast or synthetic graft so autographed is nothing but taken from the same person okay could be an intraoral tissue or an extraoral tissue. So intraoral sites we can use healing of extraction site, edendulis ridge the bony growth such as exostosis, maxillary tuberosity, the chin and the bone which is removed during osteoplasty and ostectomy so all these can be used as a graft they are the intraoral intraoral sites from which we can take up the graft and also we have extraoral sites from which we can take this the graft for implantation so they are iliac crest ribs tbl metaphysis even cranium all those can be used as a extraoral sites for graft okay. Now we have the second category that is yellow graft or allergenic bone graft which is taken from the same species so four types of yellow grafts are available one is frozen cancerless iliac bone marrow and the second one is cryopreserved bone from the head of a femur then fdba fdba that is nothing but freeze dried bone allograft and the next one is dfdba which is demineralized freeze dried bone allograft so these are the four types of allograft so the only material with human histological evidence to substantiate the regenerative user autogenous bone graft and this dfdba okay so these are the two materials which can induce the regeneration of bone and also it is important to understand the screening protocol of tissue bank that is procuring and processing the graft in donor selection processing technique and particle size the third one is xenograft xenograft is different species okay such as calf bone keel bone and an organic bone so these materials have been discarded for various reasons that is xenograft the last one is alloplast or synthetic bone grafts so a number of synthetic or inorganic graft materials are available for use in the treatment so they act almost exclusively as biologic fillers with this bone fill and very limited connective tissue regeneration and the last one is alloplast or synthetic bone graft so a number of synthetic or inorganic graft materials are available for the use in the treatment so they act almost exclusively as biological fillers with very limited connective tissue regeneration they can be classified by their ability to be biopsoped such as absorbable material or non absorbable material so absorbable materials are ceramics hydroxyapatite calcium sulfate and calcium carbonate or beta tri calcium phosphate and non absorbable or porous hydroxyapatite or bioactive glass so this bone graft materials help maintain space to facilitate the formation of bone within a confined space so they should facilitate the growth of neo vascularization and migration of osteoprogenators and the size of bone graft particles determine the resultant space available for issues formation okay so the typical size of bone graft particles ranges from hundred to thousand micrometer which is conductive to the in-growth of bone so what are the basic requirements for bone regeneration there should be blitz supply adequate blitz supply there should be proper stabilization and the presence of osteoblast and the space should be confined there should be space maintenance and the proper wound coverage so all grafting techniques require pre surgical scaling or crucial adjustment and the exposure of the defect correction of exposure of the defect using a full thickness flap and the flap technique best suited for grafting purpose is a papilla preservation flap because it provides complete coverage of the interdental area after suturing okay so the graft purpose is suited with papilla preservation flap whereas the occlusion adjustment and the exposure of the defect is done with a full thickness flap so the fate of bone graft is different once a material is placed in the bonnet effect it may act in a number of ways which may decide the fate of this material so it could be such as bone graft material may have no effect at all or the bone graft material may act as a scaffolding material for the whole side to lay the new bone or the bone graft material may itself deposit new bone because of its own viability so anything can happen so that's also now so we discussed in detail about the biologic mechanisms just osteoconduction induction and osteogenesis and various types of graft autographed allographed to xenograft and alloplastosynthetic graft so all are very very important for the exam so each one can be asked as a short not or this entire thing could be asked as a short essay so I'll come up with a new topic in dentistry and more thank you and lastly guys we have started channel membership in dentistry and more channel so you can explore various exclusives for the channel members so you can explore various options by clicking on the join button adjacent to subscribe button so we have options of personal whatsapp help so you can ask any doubts you will get answered through whatsapp text messages or voice messages and we have one more option that is the PDF notes will be available but as of now we have only the public health dentistry topic the more topics will be applauded soon and the last option is one-to-one interaction session you will get the personal interaction or personal classes on various subjects from the faculties of respective branches so explore the join button and let us know if you want any further help from us thank you