Bioactive elastin-like-recombinamer (ELR) membranes guide bone regeneration in rabbit critical size calvarial defects

To examine the effectiveness of non-mineralised and pre-mineralised elastin-like recombinamer (ELR) membranes in guided bone regeneration (GBR) in a pre-clinical rabbit model. Three pre-mineralised ELR membranes (D1, D2 and D8) and a non-mineralised (D0) membrane, along with a collagen membrane (C+) and an empty defect were randomly allocated in rabbit calvarial defects of critical size. Four weeks post-implantation the animals were euthanized and bone fill was assessed using micro CT and histological evaluation. Using micro CT, all ELR membranes led to similar bone density, as unassisted healing and healing using a resorbable collagen membrane. A trend for superior bone fill with the D2 pre-mineralised ELR membrane was observed. Histologically, at this early time-point the ELR membranes successfully guided GBR in the defects, similarly to the control collagen membrane, and additionally led to the formation of a thin woven bone layer at the top of the cranial defect bridging between the margins of the defect. As early as 4 weeks post-implantation, the ELR membranes successfully guided bone regeneration in this rabbit critical size calvarial model and a trend for superior regeneration was observed with pre-mineralised for 2 days ELR membranes. The ELR membranes led to the formation of a bony bridge parallel to the membrane suggesting bioactivity beyond occlusion of the defect. These bioactive alloplastic membranes may succesfully serve as alternatives to allogenic membranes in guided bone regeneration.