Augmentation vs Regeneration -
No Graft vs Graft

Augmentation: the action or process of making or becoming greater in size or amount.

Regeneration: the replacement or restoration of damaged or missing cells, tissues, organs, to normal form and function.

Augmentation and regeneration are very different terms, but we all tend to use them interchangeably.

To augment something is simply to make it larger. To regenerate something is to grow healthy vital tissue equal to the original. We can easily distinguish between the two terms. Bone can be augmented with metal, plastic, or any graft material that does not resorb. To regenerate bone, materials must be biocompatible and fully resorbable, resulting in bone equal to what was lost.

Regeneration is always also augmentation, but augmentation is seldom regeneration.

A finer point of bone regeneration is that simple resorption of the material is not adequate for true regeneration. For example, the bone graft material must have a biologic compound to stimulate osteoblasts to produce more bone than is found in the normal repair process. Bone repair without grafting is not equal to bone regeneration. A socket that is healed with no graft is not as healthy or as vital as normal bone, but we do know that this bone is adequate for implant support. For true regeneration to occur, you must have a biologically active process that stimulates the regenerative process, and only then can true regeneration occur.

So why is this now important for us to understand the difference between augmentation and regeneration?

It is now being recognized by a number of lecturers and professors that there is an increase in implant complication and an increase in implant failure rate in augmented sites. Dr. Bach Le of USC has produced a paper and a video lecture showing implant failure due to bone graft failure in sites augmented with xenografts, allografts, and non-resorbable synthetics. All of the studies and all of the case presentations of implant complication and failure due to bone graft failure is being reported in augmented (not regenerated) bone.

Most of our professors and lecturers have never used science-based resorbable biocompatible materials that produce normal bone. As a result, they believe that the problem is with the grafting process and not the material used in grafting.

Histologically, it is evident as to why augmented sites fail and regenerated sites do not.

The histology on the left is from a recent article in the Journal of Periodontology, at 6-months after sub antral sinus augmentation. The graft material was Bio-Oss. After 6-months, the average percent mineralization of the grafted sites was 15%. The most apical portion of the tissue samples consisted of Bio-Oss granules in fibrous tissue. The majority of the tissue consists of retained Bio-Oss particles.

It is known that Bio-Oss particles never resorb and the only thing that can possibly change in this tissue is an increase in sclerotic mineralization. This is augmentation as there is nothing normal about this tissue and it is this abnormal sclerotic tissue that is causing the increase in implant complications and increased implant failure rates seen in augmented sites.

What does regeneration look like and why is it different than augmentation?

The histology above on the right is a core sample 4 months after sub antral sinus regeneration using Sinus Graft by SteinerBio. The graft material is fully resorbed. Normal bone trabecula is present with no inflammation and the bone has an extensive vascular network that you do not see in cadaver grafted sites.

When an implant is placed in a site grafted with Bio-Oss, there will be no remodeling of the tissue, due to the sclerosis it has produced. When an implant is placed in the sinus grafted with Sinus Graft, the bone remodels to adapt to the load and integration occurs due to the newly regenerated tissue. There is no inflammation present, there is vascularization throughout, and the bone graft has been completely resorbed and regenerated into healthy vital tissue allowing for the bone to remodel according to the load.
This radiograph is from the same site as the Sinus Graft histology shown above. As can be seen in the radiograph 7 months after regeneration, the bone in the grafted site is denser than the surrounding bone, but more importantly, the new bone is healthy vital normal bone that will adapt to changes in load as any normal bone.

Let us take a look at some more augmented sites as we ask ourselves if this tissue can be expected to function as normal bone.
6 months after augmentation with non-resorbable HA.
Hydroxyapatite graft particles can be seen in black. Does anyone think this tissue can act like normal bone and support an implant without complications and an increased failure rate?
6 months after augmentation with freeze dried bone allograft.
There is no resorption of the graft particles. Areas of chronic inflammation persist. The bone has virtually no vascularity.

The dental profession has fooled itself into thinking this graft material resorbs and turns into normal bone in spite of the fact that all of the science proves it never remodels and there has never been histology showing normal bone produced by any allograft. Does anyone think this tissue can act like normal bone and support an implant without complications and without an increased failure rate?
Another freeze dried bone allograft 6 months after grafting.
Again, no remodeling of the graft particles. The new bone is sclerotic with virtually no vascular supply. This bone never “turns over” into normal bone. Does anyone think this tissue can act like normal bone and support an implant without complications and without an increased failure rate?
Implants placed in sites augmented with Bio-Oss and allograft.
Failed implant with augmented bone allograft.
The augmented bone was not integrated to the implant and was simply picked off the implant. While this is a dramatic case of cadaver bone graft failure, most bone graft failures look very much like periimplantitis and are misdiagnosed as such.
This is histology of the failed allograft/Bio-Oss graft. There is a lack of vascularization with very few blood vessels present, there are minimal osteoblasts and no osteoclasts present, and the bone that is produced is sclerotic. Lecturers and professors will tell you that these graft particles “turn over” into normal bone but here you see the graft particles more than a decade after grafting. Does anyone think this tissue can act like normal bone and support an implant without complications and without an increased failure rate?

As a comparison this is a site regenerated with Socket Graft. This bone has been in function for 6 months in a regenerated periodontal defect. The bone is healthy, vital cancellous bone capable of adapting to any load over the life of the patient. The trabeculae are thick and evenly spaced and aligned according to the load placed upon them.

This histology is from a socket 6 weeks after grafting with Socket Graft.

The pattern of bone formation and the activity of the osteoblasts with the guidance of the osteomacs shows healthy tissue regeneration at its best. This is never seen in any cadaver graft site.

This histology of a site grafted with Socket Graft shows a remarkable proliferation and migration of osteoblasts with mineralization. The multiplication and proliferation of regenerative cells is what distinguishes tissue regeneration from tissue repair. No grafting produces tissue repair with inferior mineralization, vascularity, and cell vitality compared to tissue regeneration. However, no graft is far better than the sclerotic bone produced by cadaver bone grafts.

Can the dental profession conceptualize how cadaver graft materials lead to increased implant complication and failure that is now being reported?

The first histology that was shown in this post was from an article published this year in the Journal of Periodontology. The publishing of this technique and its histology in the Journal of Periodontology implies that this is state of the art of bone graft science. Yet, there is no mention by the authors or the peer review committee that this tissue could be why we are seeing increased implant complications and failure of implants when placed in sites grafted with cadaver bone grafts. If a pathologist were to view this Bio-Oss histology, he would wonder what disease caused this atrocious tissue.

Graft vs No Graft
There is an increasing trend for lecturers and professors to point out the growing association between implant complications and implant failure in grafted sites. This recognition has led some lecturers and professors to recommend not grafting. It must be noted that these lecturers and professors have only ever used cadaver tissues throughout their careers and are unaware of the difference between augmentation and regeneration.

We at SteinerBio agree that you are much better off not grafting than using a cadaver or non-resorbable synthetic to support a dental implant. We at SteinerBio have no problem placing implants in non-grafted sites, but we refuse to place implants in sites grafted with cadaver tissue or non-resorbable synthetics.

While we have been telling the profession this for years, it is not just we that state that you should not place implants in sites grafted with cadaver grafts or non-resorbable synthetics. Because of the abnormal tissue produced by these materials, the FDA has not cleared any cadaver bone graft or non-resorbable synthetic for implant placement. They have cleared these materials for augmentation of bone as long as you do not put an implant in the site. To our knowledge, our Socket Graft and our OsseoConduct βTCP granules are the only graft materials cleared by the FDA for dental implant placement.

We like to see that the profession is halfway there. Dentistry is now recognizing that placing implants in sites augmented with cadaver grafts or non-resorbable synthetics leads to higher rates of implant complication and failure. However, the profession is still unable to pin the problem on the graft materials that they venerate and the type of tissue these materials produce. It is easier to augment bone than it is to regenerate bone. It takes more knowledge and skill to regenerate a bone than it does to simply augment a bone into some strange and unfunctional tissue.

If you want to drill into hard bone, graft with cadaver bone or non-resorbable synthetics.
If you want to drill into healthy bone, use SteinerBio regenerative bone graft products.

Periodontal treatment outcomes have not improved in 30 years. The reason is that our profession is stuck with the misguided notion that allografts regenerate bone. Allografts have no regenerative properties and trying to regenerate periodontal tissues with a material not capable of doing so has lead the profession into a hole from which there is no way out. Periodontics will continue to fail to improve treatment outcomes until it abandons cadaver tissue and turns to science-based regenerative materials.

When our profession makes the switch from augmentation to regeneration, it will usher in a new exciting era of tissue regeneration that will lead to our ability to return our patients back to normal form and function with predictable long term implant success.


American Society for Bone and Mineral Research (ASBMR)

Tissue Engineering and Regenerative Medicine International Society (TERMIS)