Xeno-synthetic bone block includes cellular remnants: Acceptable components or lack of purification?

Naturally derived bone substitute materials have to undergo controlled purification processes to be suitable for clinical application. The aim of the present article is to analyze the structure and composition of a new commercially available bovine-derived bone substitute material, SmartBone®, for the presence and localization of organic and inorganic constituents. Standardized conventional methods were performed for the histological analysis using hematoxylin and eosin, Azan, Masson-Goldner trichrome, as well as specific tartrate-resistant acid phosphatase staining, and were evaluated by light microscopy. The results showed a calcified trabecular structure with preserved lamellar substructure. In addition, organic structures were found within the osteocyte lacunae, the haversian canals, and the inter-trabecular region. The presence of organic remnants within the bone block raises the question on what extent including organic material could affect the regeneration process and application safety in clinical settings and whether including specific organic material such as collagen could be beneficial for bone regeneration. Thereby, further preclinical and clinical studies are necessary to evaluate the bone block examined here and to determine whether a clinician should accept the organic remnants within bone blocks.