Discussion Topic: Cortical vs Cancellous Graft Material

I'm no expert but this is what works best for me, demineralized cortico-cancellous bone, Mineross or Allosorb are two great brands. brands. Here's a simple rationale mineralized, cortical takes a long time to resorb, demineralized cancellous resorbs too fast. The combo is just right! (Sounds like Goldlocks!) I let it heal 14-16weeks. I've tried them all autologous, allograft and xenograft. But for the sockett application this works well. Two key point good buccal plate and primary closure, collaplug or membrane coverage for good soft tissue preservation. Bio-coll works well but I use Allosorb. Enjoy, now I know the smarter guys will post next!

Bone tissue is a matrix- like  structure, primarily composed of a protein called collagen.  It is strengthened by hydroxyapatite, deposits of calcium and phosphate salts.  4 types of bone cells are located within and around this matrix. Together, this 4 types of cells are responsabile for building the bone matrix , maintaining it and remodeling the bone as needed.  The 4 types of bone cells are: - Osteoblasts, which produce the bone matrix. - Osteocytes, mature osteoblastes that maintain the bone. - Osteoclasts, which break down and remove bone tissue - Bone lining cells, which cover bone surfaces. There are 3 ways that a bone graft can help repair a defect: -Osteogenesis, the formation of new bone by the cells contained within the graft. - Osteoinduction, a chemical process in which the molecules contained within the graft ( bone morphologic proteind BMP) convert the patient's cells into cells capable of forming bone -Osteoconduction, a physical effect whereby the graft matrix configures a scaffold on which cells in the recipient, form new bone.  Autograft : bone patient's own body Allograft: bone from a human cadaver. Mineralised or Demineralised ( bone that has had Its calcium removed ). BMP are strong inducers of bone growth ( osteoinductive). Xenograft: bone from animals ( bovine or equine) Alloplast: synthetic bone made from calcium phosphate or cacium sulfate or hydroxyapatite, or ceramic bears

The simple answer to your question is; you have the option of using the patients bone or the bone of another human or animal. Grafting purist believe that autogenous bone is the only way to go. Cortical autogenous has a more dense matrix, with less water and subsequently less viable cells to allow for induction. Cancellous bone on the other hand has more water and more cells that have the potential to allow for actual bone growth. There is some argument as to wether the cells remain viable, once transplanted from harvest to graft site, but there is little science to suggest that there a better material. The demineralization process was thought for the longest time, to be what made demineralized bone work the way it does, but as you have probably noticed, this process is growing out of favor and a lot of doctors suggest mineralized bone hangs around a bit longer. Your question inquired about socket preservation, I do believe, so with regards to that, I encourage taking greater time to consider your graft bed and how you choose to contain whatever material you may choose. This is absolutely the most important facet of socket preservation grafting. There are some strong studies that prove, if the graft site is prepared appropriately and ingrowth of epithelium is prevented, some sites need no material at all. This is not to say you must have primary closure. If you are proficient at harvesting bone, the morbidity is negligible and it is very cost effective. If you are asking the question, then I am assuming you are new to this part of dentistry. Several surgeons in my town use only mineralized bone and get great results. Take a good guided tissue regeneration course. Socket preservation grafting is actually quite enjoyable and very predictable. Once you become more comfortable, you will find that you can save the patient time and money, by placing implants in the extraction site and apply the same techniques, with excellent results. Find a good resorbable membrane that works well in your hands and you will be amazed at how simple this stuff is. Bvinci

Very good explanation.Thank you, Sir.

i don't think your initial question was ever answered fully, so i'll make some brief comments here 1. cortical vs. cancellous- cortical bone is generally more dense and resorbs more slowly than cancellous bone, which is less dense and contains more cellular and protein components. some evidence exists that cortical bone may be more advantageous for socket grafting as it resorbs more slowly, and as long as it is present soft tissue is less likely to envaginate downward. 2. are they both osteoinductive- cortical bone is much less likely to have osteoinductive potential as it contained less protein, and bone morphogenic proteins (bmps) are largely responsible for inductivity. having said that, the concept of inductiveness has much more to do with processing than with the original source of the bone. for instance, if they've both been cooked to produce anorganic bone matrix, the proteins are incinerated and all that is left is mineral, so no osteoinductiveness exists, only osteoconductiviy. 3.mineralized vs. demineralized- now we are talking the potential for osteoinductiveness. demineralized means mineral content has been removed, leaving protein behind, so these can be inductive. mineralized means ha content is still there, proteins are removed, and these are largely conductive only 5. best material- is no such animal. most processed bone grafting materials work given enough time to be resorbed and turned into bone. in theory, the "best" would be a combination of mineralized and demineralized material. the mineralized would resorb more slowly and maintain the space, while the demineralized would potenially provide inductivity. so mixtures or combination products may have an advantage. gary

I have bone done many types of socket and ridge preservation osseous grafting procedures for more than 15 years. I like the explanations of E. Wade, Baker K Vinci and Gary Henkel . They are thoughtful and well done. While I tend to prefer mineralized bone as I believe it is more stable and provides an excellent scaffold for new bone to grow through and mature. I always wait 16 weeks for my grafts to mature unless they are larger grafts or Sinus lifts in which I wait 6 months. My only addition to the previous information is that I believe that periodontists prefer demineralized bone when doing any bone grafting or regenerative procedure around existing teeth. The reason for this is that the protein left behind in the demineralized bone has inductive potential for regaining periodontal ligament. For this reason and only this reason would I use demineralized bone perhaps in concert with Emdogain. Good Luck, David

I'm embarrassed to say I was not aware of the inductive capacity of any allograft. If that is the case then we should be using demineralized bone in all socket preservation grafts, since they all tend to be next to an adjacent tooth. Bvinci

wow...please read some of Dr. Gerald Bowers landmark research. Thank you....DrT

DrQ....you definitely have too much spare time on your hands. Have you ever thought of getting a job writing for SNL...or possibly Steven Colbert of Jon Stewart??

Baker, The regenerative potential of demin allograft as its being discussed here is related to periodontal defects, not extraction sites. There was a study published recently by Mellonig using Puros mineralized allograft in periodontal defects that had human histology and showed regeneration in a limited # of cases. However it's important to note that Puros is not your typical FDBA, because of the "Tutoplast" that they use, and it's never freeze dried. There is a paper published by Wood and Mealey that showed DFDBA yielded more vital bone then FDBA in single rooted extraction sites when re-entry with bone trephine cores were used to give the histomorphometric analysis. There is a new material on the market by Osteogenics, Encore, which combines both DFDBA and FDBA into a single vial. In the end, everyone should read the literature, and make a decision for what is best for their patients, in their hands. It is likely that any of the allografts will give a good result given good technique and enough time. In our clinic we have seen that sites grafted with DFDBA sometimes do not look as great (due to lack of mineral content) on either the CBCT or PAs at the time of placement, however the grafts are rock solid surgically. TB

The only osteoinductive and osteoconductive bone graft is Autogenous bone graft & all other types of bone replacing materials are osteoconductive only. To preserve the socket volume and reduce bone resorption after extraction there is no evidence base on certain method, but I prefer to fill the socket with artificial bone graft and covered with collagen membrane.

There are many differences between cortical and cancellous bone while living but the only difference when dead is the mineral content. Cortical bone in about 95% mineralized tissue and cancellous bone is between 35 and 45% mineralized tissue. Neither cortical or cancellous bone allografts are osteoinductive or osteogenic and these terms are rarely understood. An osteoinductive substance is a material that has the ability to grow bone outside of bone. An osteogenic substance is a material that modifies the physiology of the osteoblasts and stimulates the osteoblast to produce bone at a faster rate than bone would grow if the substance was not present. But don't believe me on these terms contact the FDA for clarification. The proteins in allografts produce inflammation not bone growth. You are putting proteins from another person into your patient without any effort to match the proteins and you think there will not be an inflammatory response? I have never seen a paper or a patient where an allograft is resorbed. Most sites grafted with allografts are hard and highly mineralized but you sacrifice bone vitality and the ability to respond to changing loads for mineral density. Sorry to gore some sacred cows. Greg Steiner Steiner Laboratories

Greg, you continue to suggest we go to the FDA for explanations, proof of efficacy, or clarification of some of the science. Certainly you can't be serious, when you use them as your reference? You are parsing words. With regards to the suggestion that only autogenous bone is inductive, there is still some strong data supporting BMP 's role as an inductive medium, despite the cooked study results and the rare adversities noted in the cervical reconstruction arena. Bvinci

Greg, Interesting article..... I'm sure you and everyone else can appreciate how difficult of a study it is to obtain evidence (or the lack thereof) of osteoinductivity in actual human treatment, both from a study design and an ethics standpoint. The authors of the article do state the limitations of their study, mainly the very small sample set, and the use of only one donor lot. Certainly they could have seen radically different results with another lot of DFDBA or with a different study model. Also, it's not exactly representative of a true test of induction, since the material was placed inside a synthetic housing, which was likely "mobile" during the healing process as most membranes are. Also their "definition" of osteoinductivity is certainly one that is strict, although seemingly accurate. Perusing the other available literature, I did find an interesting article regarding osteoinduction, which makes some good points about clinical testing in various animal models. Habibovic and De Groot, 2007 Osteoinductive biomaterials–properties and relevance in bone repair J Tissue Eng Regen Med, 1 (2007), pp. 25–32 Baker do you know of any literature from the spinal orthopedic surgery land that shows induction with Infuse saturated grafts or sponges? Mind wide open, and full of skepticism......

Guys, look at the forest and ignore the trees. Mineralized allografts and xenografts have a long history of success when used with implants. The success rate of implants placed into sinuses and ridges grafted with these materials is comparable to that of implants placed into native bone. Histological studies confirm that there is a bone/implant interface between the graft particles and the implants. So, whether or not the clinical/histological behavior of these materials hews to the FDA definitions of osteoinduction or osteogenicity is immaterial if they are safe, predictable and effective...and they are.

In general, which usually yield better success in grafting a socket for the implant placement in posterior max.? the 50:50 mixed demineralized cortical and cancellous or 50:50 mixed demineralized and mineralized cortical ( or cancellous ) Please give me your comment. Thanks.

whats you opinion about mixture of allograft and xenogtafts 50/50 for exposed implant on dehiscenced area ?