Biological concept that makes sinus grafts successful?

Generally the cortex on the floor of the sinus is very thin, and the bone tends to be very vascular, so decortication isn't necessary. How do I know? Because it works very well by just elevating the membrane and placing the graft. As a matter of fact, I worry more about excessive bleeding and arteries in the lateral sinus wall more than I do that the graft won't have a good blood supply.

Extensive blood supply from medial wall of sinus

It's sinus membrane that plays the most important role in bone regeneration.... It acts exactly like the periosteum... plenty of bmp's and growth factors... There are so many articles in journals with big implact factor which prove that scientifically.

With all the richness of the sinus in blood supply, why are we adding prf? What is the difference between good and gooder? What kind of bone are we regenerating, cortical, cancellous and cortical?

Now bone grows around implant even if you do not add bone. Some only stuff prf in to elevate the sinus safely and then place implant into the prf. Bone grows over the implant regardless based on histological studies (animal models). So the OP doesn't have to worry much at all.

Interestingly, Carl Misch, let him rest in peace, recommended that the sinus must be scratched to activate the so-called Acceleratory phenomenon.

Some comments may be misleading. Sinus membrane has very poor blood supply and poor regenerative potential see "Laser Doppler Flowmetry for clinical detection of blood flow as a measure of vitality in sinus bone grafts", in Implant Dentistry Vol 9 issue 2, 2000. PRF is important to line the sinus membrane where perforations and tears can be unseen undetected, to reduce risk of extravasation of particulate graft contents into the sinus space which can lead to gross and chronic sinus infections and ENT referrals in severe cases. As to its contribution to osseous regeneration in sinus grafts yet unknown.

Kavan Wong, it looks like we are on the same page in understanding what goes on in the sinus. What is your opinion of the results of sinus graft? Do we get new bone growth integrated with the osseous floor of the sinus or something of a different kind? What is the histology of the "mushroom" we see on the x-ray and where we place the implant? Assuming from the implant stability it must be of a cortical bone quality.

I guess the most important part is what you put in ......simple really if you want a nice very white "mushroom " use a HA ( xenograft ) , if you want host bone then need a synthetic ( BTcP ) or PRF ....... with these materials we notice that in a few weeks the well defined cortical plate become less apparent on radiograph as the new host bone in the lifted area regenerates . Due to the vascularised nature of the site we load cases at 8 weeks even with low initial ISQ readings ...

I don't agree that the sinus is lined with cortical bone. My histologic sections of the floor of the sinus fails to show any cortical bone. The anatomy of the sinus shows the sinus membrane without a distinctive periosteum and I do not see a cambrial (osteogenic) layer at all. Under the sinus membrane is an osteoid layer but not one lined by osteoblasts. This osteoid like layer is lined by resting cells that I believe are extracting mineralization at a glacial pace hence pneumatization of the sinus. The lack of a cambrial layer explains why the sinus membrane provides no bone formation. All of the bone growth comes from the surrounding bone not the the sinus membrane. This is obvious to anyone who uses biocompatible materials that are resorbed because with these materials you can see the mineralization grow from the bone out to the elevated sinus membrane. None of the blood supply comes from the blood vessels in the sinus but it is provided by the bone. In fact, with our Sinus Graft the osteoblasts migrate into the graft ahead of the blood supply. If you are using nonbiocompatible graft materials like cadaver bone the process is different but that is another story.

Greg Steiner, What is the story with cadaver bone in the sinus? What are your credentials ? Everything you said is interesting but does not provide all the answers to the success of grafts in the sinus.

Greg Steiner, So how do you explain the use of demineralized graft material? Would you feel comfortable making the statements in front of people with degrees in bone physiology. Somehow I get a feeling that what you are saying is your concept of the process of bone regeneration and it is superficially logical but not very scientific.

This is for you Mr. Greg Steiner, Clin Oral Implants Res. 1995 Sep;6(3):155-63. Bone apposition onto oral implants in the sinus area filled with different grafting materials. A histological study in beagle dogs. Wetzel AC1, Stich H, Caffesse RG. Author information Abstract The placement of oral implants into jaw bone has a high predictability provided an adequate bone volume surrounding the implant is present to ensure primary stability and resistance to functional loading forces after completion of osseointegration. In the distal area of the maxilla, an adequate bone volume is often lacking because of the proximity of the sinus cavities. The aim of this study was to evaluate histologically the simultaneous placement of endosseous implants into the sinus cavity and the surgical elevation of the sinus floor including filling the cavity with different grafting materials. In 9 sinus areas of 5 beagle dogs, 9 titanium implants (ITI Dental Implant System) were placed, and the void space of the sinus cavity was filled simultaneously with either demineralized freeze-dried human cortical bone (Musculoskeletal Transplant Foundation), resorbable hydroxyapatite (Osteogen) or natural cancelleous bovine bone mineral (Bio-Oss). To study bone formation, fluorochrome markers (tetracycline HCl and calcein green) were used at 2 and 8 weeks. Clinically, all implants healed uneventfully, and 5 months after implant placement the dogs were killed for histologic evaluation. All implants exhibited osseointegration within the pre-existing cortical bone of the sinus floor. The implants surrounded by freeze-dried bone xenografts yielded no formation of new bone, whereas the sites with hydroxyapatite or natural bovine bone mineral demonstrated newly formed bone with direct contact at the implant surface. The average extent of bone to implant contact was 25% (SD = 10.6%) and 27% (SD = 8.8%), respectively in relation to the length of the originally denuded implant surface.(ABSTRACT TRUNCATED AT 250 WORDS). Please note the wording: "..pre-existing cortical bone of the sinus floor..."

I know nothing about dog anatomy.

Dear Mr. Steiner, It is great to see your latest response or comment. From the position of your comment in relation to my latest response, I am not certain if you did read the outcome of the study I copied verbatim. I would be delighted to see your response to that study. If what you say is true then everything that is going on with the (call it) science of GBR is worthless. All the money, all the claims, all the expense to the patient has no merit. There is calcium sulfate that is inexpensive and easy to use to achieve bone regeneration. What is your conclusion to what you claim to be the answer according to your science? Other than the club you belong to, is there any formal organization that supports your findings?

Mr. Steiner, Is your research done on humans? Nobody would expect someone like yourself to be familiar with dog anatomy but everybody would expect that someone with opinions like yours would understand the parallel conclusions from research on dogs. The other issue is that it is not anatomy we are talking about but histology and bone physiology.

Mr. Steiner, There is no point in carrying on. I will just express my opinion as frankly as I know how. You are a pseudo scientist with pseudo scientific conclusions and what you preach is nothing other than hogwash. It is irritating to see people like yourself discredit the hard work of those that provide scientific conclusions we benefit from. Never heard of Steiner Biotechnology and hope nobody is influenced but this nonsense.