Guided Bone Regeneration with REGENFAST®: Preliminary histological features

Advancements in Bone Regeneration

New strategies are being developed to accelerate bone maturation of augmented alveolar ridges. Recently, a mixture of demineralized bovine bone particles (Geistlich Bio-Oss®) with a combination of polynucleotides and hyaluronic acid (REGENFAST®) has been proposed for vertical/horizontal alveolar bone regeneration in partially edentulous patients. Preliminary clinical data appear to be promising.

Importance of Histological Data

Histological and histomorphometric data are essential to evaluate the regeneration process in terms of quality and quantity of the newly formed tissue. Bioptical specimens were retrieved during implant placement about 6 months after Guided Bone Regeneration (GBR) and processed for histological analysis without prior decalcification.

First Sample Observations

Evidence from the first samples (Fig. 1) shows the formation of highly mineralized and well-organized viable new bone, totally incorporating the biomaterial remnants. Several residual granules can be observed in close contact with the regenerated bone which appears to stratify at the edges of the fragments with many osteoblastic-like cells lining the borders of bone regeneration.

Figure 1. Undecalcified histological sections from sites regenerated with Geistlich Bio-Oss® and REGENFAST® mixture at 6 months. Toluidine Blue and Pyronin Yellow staining. In blue: osteoid and cells, in purple: tissue in phase of mineralization, in brown: Geistlich Bio-Oss® and highly mineralized bone. Red asterisks indicate residual grafted particles; blue asterisks depict areas of regenerated bone; green asterisk shows blood vessels in the marrow spaces; yellow arrow indicates a front of osteoblast-like cells (the samples were taken during surgeries performed by Dr. Mario Beretta, Dr. David Palombo and Dr. Federico Rivara).

Advanced Tissue Maturation Insights

In most areas, tissue maturation seems to be at an advanced stage, with the lamellar aspect prevailing over the woven bone features. The osteoid matrix is minimal when considering the initial time of surgical re-entry. The ground sections analyzed showed only a few resorption lacunae, while the deposition activity is clearly evident. The medullary spaces filled with numerous large blood vessels, were populated by many cells but were free of inflammatory infiltrate.

Promising Preliminary Data

Preliminary conclusion: the current histological characteristics may suggest the formation of a significant amount of new vital bone in the phase of physiological remodeling and perfectly osseointegrating the grafted particles. Further clinical studies will investigate the clinical benefits of adding REGENFAST® to Geistlich Bio-Oss® for Guided Bone Regeneration in more detail, for example focusing on the question if addition of REGENFAST® accelerates bone regeneration and allows for an earlier implant placement.