Bone Regeneration:
When Science Means Nothing

We aim to provide useful information and pass on knowledge that we believe will ultimately help provide the best for our patients. Most of the time, we offer tools, tips, and techniques for practical use. However, there are moments where we are bound to address an issue and present criticism when our profession lacks the ability to understand what they are saying.

We believe the topic of this article is too important to ignore and must be discussed. Today we will look at an in vitro bone regeneration study and assess the value of their findings.
Comparative in vitro study of commercially available products for alveolar ridge preservation
J Periodontol . 2022 Mar;93(3):403-411. doi: 10.1002/JPER.21-0087. Epub 2021 Jul 12.
The study purpose was described as:

To investigate how different commercially available ridge preservation products might perform clinically: Helistat (collagen control), OsteoGen Plug, Bio-Oss Collagen, and J-Bone.

The study grew cells in the laboratory and used a series of sophisticated scientific methods including scanning electron microscopy, microcomputed tomography, helium pycnometry, and infrared spectra analysis to monitor and evaluate cell growth and the production of various proteins involved in the mineralization process.

In vitro studies for bone regeneration are worthless for gaining any clinically applicable information. Any of our readers should know that the immune system is a determining factor regarding bone regeneration. The immune system is required to initiate regeneration and if an inflammatory response becomes chronic, bone regeneration will not occur. In our previous emails we have focused on the importance of the immune system in bone regeneration, but in addition for bone regeneration to occur, just about every other biologic process needs to be present to grow bone. The evaluations performed in this study do not come anywhere near duplicating what happens in actual bone regeneration.

The type of scientific evaluations done in this study may be of some value in product development, but they should never be used to come to any clinical conclusions. The problem with this paper is not the science, but authors state the purpose was to “To investigate how different commercially available ridge preservation products might perform clinically…” Nothing in this publication has anything to do with how these products might perform clinically and it shows a lack of understanding of the bone regenerative process to make such a statement. Likewise, this paper was published in the Journal of Periodontology and it is obvious that by allowing such inaccurate statements to be made it shows whoever is reviewing the paper also lacks an understanding of bone regeneration. In vitro studies never give any valuable information about a product’s clinical performance. In vitro studies should never be used to compare the potential clinical performance of a product and it is especially egregious to use in vitro studies to compare the potential performance of various products.

A good example of how using in vitro studies to make clinical judgements can harm our patients is biphasic bone graft products composed of beta tricalcium phosphate (βTCP) and hydroxyapatite (HA). These products showed great performance in in vitro studies in the laboratory. Somehow they made it past the FDA and onto the market. Histology of these products showed pockets of graft material encased in fibrous tissue. The material was neither osteoconductive or resorbable. Only in vivo studies should be used to evaluate a product’s ability to grow bone.

For information on how the immune system affects bone regeneration please see the following:


American Society for Bone and Mineral Research (ASBMR)

Tissue Engineering and Regenerative Medicine International Society (TERMIS)