Cadaver Bone Grafts Linked to Higher Rates of Bone Loss and Implant Failure

With our primary focus centered on bone and bone regeneration, we have continuously evaluated bone in relation to dental implant failure. Hence, we began noticing 10 years ago that the majority of marginal bone loss and implant failures were occurring in sites grafted with cadaver bone. Since that time, we have studied the biology of the various bone grafts to determine if one type of bone graft produces different bone than another. Our findings supported the conclusion that cadaver bone grafts do not produce normal bone and therefore explains the observed increase in marginal bone loss and implant failure rates.

Allografts and Bio-Oss have no long-term studies that support placing implants in sockets grafted with these materials. However, we now have studies that have evaluated bone loss and implant failure for implants in sockets grafted with cadaver bone grafts and the results are damning.

Since our initial hypothesis over 10 years ago, it appears clinical research has caught up with clinical observation. Let’s look at three studies that evaluated these materials at three different time frames. As you read the summaries, you can click on the images to jump to the corresponding articles:

Title: Crestal bone resorption in augmented bone using mineralized freeze-dried bone allograft or pristine bone during submerged implant healing: a prospective study in humans.
Clin Oral Implants Res . 2016 Feb;27(2):e25-30. doi: 10.1111/clr.12512. Epub 2014 Nov 10.

Study done at Tufts Dental School, published in the Journal of Clinical Oral Implants Research.

Results: A total of 29 implants in 26 patients, 11 in augmented bone (test group) and 18 in pristine bone (control group), were analyzed. The mean peri-implant bone loss (ΔBL) was 0.74 ± 0.74 mm (mean ± SD) in the test group and 0.25 ± 0.55 mm (mean ± SD) in the control group. The differences between the test and control groups in the mesial, distal, and mean peri-implant crestal bone level changes were statistically significant (P = 0.009, P = 0.004, and P = 0.001, respectively).

Conclusions: More peri-implant crestal bone loss during the submerged healing period was observed in augmented bone than in pristine bone. Augmented bone may not exhibit the same characteristics as pristine bone during the implant submerged healing period.

After 3 months of being submerged, the implants in sockets grafted with allografts resulted in significantly more marginal bone loss than those implants placed in un-grafted bone. They have concluded that sockets grafted with mineralized freeze-dried bone allograft have a type of bone that is abnormal. We have described this process as fracturing of sclerotic bone during implant placement resulting in marginal bone loss.

Title: Relationship Between Osteoporosis and Marginal Bone Loss in Osseointegrated Implants: A 2-Year Retrospective Study.
J Periodontol . 2016 Jan;87(1):14-20. doi: 10.1902/jop.2015.150229. Epub 2015 Sep 3.

Study done at University of Seville Dental School, Seville, Spain, published in the Journal of Periodontology.

Results: When the sample is evaluated only in selected implants (one per patient, n = 67), significant differences appear to relate only to the MBL (marginal bone loss) with the placement of implants in regenerated bone sites (P <0.001).

Conclusions: Osteoporosis (as evaluated by MCI) does not pose a risk for the development of greater MBL (marginal bone loss). Parameters adversely affecting the development of increased MBL are a previous history of periodontitis and especially the placement of implants at sites of bone regeneration (cadaver bone graft). Again, this study shows that cadaver bone grafts produce sclerotic bone and fails at a much higher frequency than normal bone.

Title: Comparison of Three Different Types of Fixed Partial Implant Prosthesis: A Long-Term Retrospective Study of Clinical Outcomes and Cost Effectiveness.
Clin Oral Implants Res . 2019 Apr;30(4):295-305. doi: 10.1111/clr.13415. Epub 2019 Mar 29.

Study done at University of Michigan Dental School, published in the Journal of Clinical Oral Implants Research.

Augmented vs non-augmented sockets were evaluated on a patient basis and on an individual implant basis. The findings are as follows:

Level of statistical significance p. 0.05

The augmented sockets showed statistically greater incidence of peri-implantitis and implant failure throughout the study. This study was purportedly done to evaluate different prosthetic designs. However, the number of augmented sites was included and the statistics showed a startling difference between sites that were augmented and sites that were not augmented. They established that augmented sites develop significantly more bone loss with higher implant failure than non-augmented sites.

Our profession does not know how cadaver bone grafts produce mineralization. Some lecturers still profess that allografts are osteoinductive, but this has been proven false. All dentists believe that allografts are resorbed, but there has never been a study that shows resorption of the graft material at any time frame. Studies that look at allografts at different time frames show the same amount of residual graft materials. Our profession not only has no scientific support for the use of these materials in extraction sockets, but in addition, our profession is ignoring good science that clearly shows these materials produce a higher level of bone loss and implant failure. Until studies are published that show cadaver bone grafts produce a success rate equal to non-grafting or grafting with resorbable, biocompatible bone grafts, these cadaver bone grafts should not be placed in sockets that will receive an implant.

While the profession will resist recognizing the failure of what they have been teaching for the last 30 years, the dentist can simply ask each patient who has a failing implant if the site was grafted. You will then realize for yourself that the vast majority of failing implants today are in sites grafted with cadaver bone grafts.

The first study done at Tufts University discussed abnormal bone produced by allografts. For a better understanding of this bone and how it affects implant failure, click on the following article below:

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Cadaver Bone Grafts Linked to Higher Rates of Bone Loss and Implant Failure

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