When discussing particulate bone grafts, the consensus among dentists is that autografts are the “gold standard” for maxillofacial bone grafting. Allografts are considered the next best substitute with xenografts considered the best for bone volume maintenance. So obviously the studies comparing harvested bone grafts to beta tricalcium phosphate must show that harvested bone is superior right?
Wrong.
There have been a number of well done, head to head studies that have compared βTCP to various types of harvested bone grafts and we are unaware of any published human clinical study where autografts, allografts, or xenografts have outperformed βTCP. The studies listed below found that βTCP was equal to or better than autografts, allografts or xenografts. In addition, most of these studies compared the older second generation βTCP and not the new third generation βTCP. When a third generation βTCP was compared to allografts, autografts, and infuse in a controlled animal study, the βTCP significantly outperformed all other bone grafts.
So why does the dental profession still think harvested bone is superior? Hopefully we will hear from our readers as to why they think harvested bone is better but until then, here is a list of studies that compared βTCP to autografts, allografts, and xenografts for you to make your own conclusion.
Why Do Dentists Think That Cadaver Bone Grafts Are Superior To Synthetic Bone Grafts?
Does Graft Particle Type and Size Affect Ridge Dimensional Changes After Alveolar Ridge Split Procedure?
J Oral Maxillofac Surg. 2018 Apr;76(4):761-769. doi: 10.1016/j.joms.2017.11.002. Epub 2017 Dec 2.
Conclusion: This ridge split study found that beta tricalcium phosphate granules produced statistically superior results over allograft granules for all particle sizes. In addition, larger particles (1-2mm) performed superior to smaller particles (.5-1 mm).
A prospective multicenter randomized clinical trial of autogenous bone versus beta tricalcium phosphate graft alone for bilateral sinus elevation: histologic and histomorphometrically evaluation.
Int J Oral Maxillofac Implants. 2005 May-Jun;20(3):371-81.
Conclusion: At 6 months there was no difference in the amount or quality of bone between the two groups.
Long-term changes in graft height after maxillary sinus floor elevation with different grafting materials: radiographic evaluation with a minimum follow-up of 4.5 years.
Clin Oral Implants Res. 2009 Jul;20(7):691-700. doi: 10.1111/j.1600-0501.2008.01697. x.
Conclusion: After 4.5 years there was no difference in the amount of bone regeneration between the autograft and beta tricalcium phosphate groups.
Maxillary sinus floor augmentation using a beta-tricalcium phosphate alone compared to autogenous bone grafts.
Int J Oral Maxillofac Implants. 2005 May-Jun;20(3):432-40.
Conclusion: Both autograft and beta tricalcium phosphate grafts produced adequate bone for implant placement and both materials had a 100% implant success rate after one year.
Osteoinductive ceramics as a synthetic alternative to autologous bone grafting.
Proc Natl Acad Sci U S A. 2010 Aug 3;107(31):13614-9. doi: 10.1073/pnas.1003600107. Epub 2010 Jul 19.
Conclusion: This was a critical size defect in sheep that found a third-generation beta Tricalcium phosphate yielding significantly more bone production than autograft and BMP2.
Early implant survival in the posterior maxilla with or without beta-tricalcium phosphate sinus floor graft.
J Oral Maxillofac Surg. 2010 Jul;68(7):1642-5. doi: 10.1016/j.joms.2009.08.028. Epub 2010 Apr 10.
Conclusion: Sinuses were grafted with beta tricalcium phosphate with simultaneously placed implants. This group was compared to maxillary posterior implants that were placed without the need to do sinus augmentation. Both groups experienced 99% success rate after approximately 30 months.
Chronic infection and infected non-union of the long bones in pediatric patients: preliminary results of bone versus beta-tricalcium phosphate grafting after induced membrane formation.
Int Orthop. 2018 Feb;42(2):385-393. doi: 10.1007/s00264-017-3693-x. Epub 2017 Nov 28.
Conclusion: In the treatment of chronic osteomyelitis, beta tricalcium phosphate performed better than allograft.
Use of autogenous bone and beta-tricalcium phosphate in maxillary sinus lifting: histomorphometrically study and immunohistochemical assessment of RUNX2 and VEGF.
Int J Oral Maxillofac Surg. 2017 Apr;46(4):503-510. doi: 10.1016/j.ijom.2017.01.002. Epub 2017 Feb 6.
Modern beta tricalcium phosphate bone grafts perform as well or better than allografts or autografts. The negatives of autograft morbidity and cadaver harvesting makes high performing βTCP a superior choice.
Conclusion: Beta tricalcium phosphate alone performed better than βTCP when combined with autograft and better than autograft alone.
So again, why does dentistry think that autografts, allografts, or xenografts are superior when there are no studies to support that conclusion?
To understand that we need a history lesson.
In the 1970s and 1980s, the promise of regenerating tissues became a possibility with the discovery of stem cells and molecules such as BMP-2. These discoveries prompted many scientists to invest their time and intelligence into developing materials and methods to regenerate lost tissues to great fanfare. The great fanfare about tissue regeneration led scientists to establish companies to market tissue regeneration products. However, because these were new products the regulatory requirements were burdensome and it was soon discovered that the costs required for FDA approval was overwhelming and virtually all of these companies folded as a result in the 1990s.
So what happened next?
The clinicians still wanted the ability to help their patients, so they turned to cadaver tissues. As transplant cadaver tissues did not require any FDA involvement, the materials went from the tissue banks to the clinicians and then to the patients without the scientific evaluation required for FDA evaluated products. The theories about how these tissue worked in patients were proven wrong, but the studies were ignored and the theories became dogma. Because the scientists are bypassed still today, no one knows what these tissues are doing in their patients. No one knows how mineralization is produced, what kind of bone is produced, or how long an implant will last when implants are placed in sockets grafted with these materials.
Allografts and xenografts never produce normal bone and this will ultimately be their downfall.
Autografts do not stimulate bone formation, but they are fully resorbed and they do produce normal bone.
The biggest use of allografts and xenografts is for grafting sockets. Obviously they must perform well for that purpose right? Wrong, because no one has studied the success rates for implants placed in sockets grafted with allografts or Bio-Oss. What I have just said is remarkable, but true. There are no legitimate studies on the success rates on implants placed in sockets grafted with allografts or Bio-Oss at any time frame. Yes, there is one dubious Puros study that no one but a Puros sales rep would consider science, but that is it. However, we do have good legitimate studies for implants placed in synthetics.
Implants placed in PerioGlas (Novabone) were found to have an 88% success rate over three years of loading. Socket Graft™ was found to have a 100% success rate after three years of loading. You have a scientific basis for placing implants in sockets grafted with synthetics, but you have no scientific basis for placing implants in sockets grafted with allografts or Bio-Oss.
A factor related to implant success and failure is marginal bone loss. We have two recent, very well done studies that have shown that cadaver bone grafts cause marginal bone loss. This is irrefutable. Sockets that have not been grafted and sockets grafted with resorbable bone grafts have never been shown to produce marginal bone loss.
To recap:
- All studies have found modern synthetic bone grafts to perform equally or superior to cadaver bone grafts.
- We know cadaver bone grafts result in marginal bone loss.
- The success rate of allografts and Bio-Oss have never been studied in regard to implants placed in sockets grafted with these materials.
Retrospective cohort study of 4,591 dental implants: Analysis of risk indicators for bone loss and prevalence of peri-implant mucositis and peri-implantitis.
J Periodontol. 2019 Jul;90(7):691-700. doi: 10.1002/JPER.18-0236. Epub 2019 Feb 6. French D, Grandin HM, Ofec R.
Dental implants are remarkably successful when placed in normal bone. Offices that use synthetic bone grafts that fully resorb and produce normal bone also report a 99% implant success rate over the same 10 year time period. If you want a 99% success rate over 10 years you need to place your implants in normal bone. Autografts, no grafts, and synthetics all produce normal bone and will give you a 99% success rate over time. Place your implant in cadaver bone and you have no idea how long it will last.
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