Potential lack of ‘‘standardized’’ processing techniques for production of allogeneic and xenogeneic bone blocks for application in humans S. Ghanaati a,b,⇑ , M. Barbeck a,b , P. Booms a,b , J. Lorenz a,b , C.J. Kirkpatrick b , R.A. Sader a a Department of Oral, Cranio-Maxillofacial and Facial Plastic Surgery, Medical Center of the Goethe University Frankfurt, Frankfurt am Main, Germany b Institute of Pathology, University Medical Center, Johannes Gutenberg University, Mainz, Germany article info Article history: Received 10 December 2013 Received in revised form 9 April 2014 Accepted 16 April 2014 Available online xxxx Keywords: Allogeneic (DIZG Human Spongiosa, Puros Allograft Spongiosa Ò ) Xenogeneic (Tutobone Ò , OsteoBiol Ò Sp, Bio-Oss Ò ) Bone blocks Bone tissue engineering abstract In the present study, the structure of two allogeneic and three xenogeneic bone blocks, which are used in dental and orthopedic surgery, were histologically analyzed. The ultimate goal was to assess whether the components postulated by the manufacturer can be identified after applying conventional histological and histochemical staining techniques. Three samples of each material, i.e. allogeneic material-1 and -2 as well as xenogeneic material-1, -2 and -3, were obtained commercially. After decalcification and standardized embedding processes, conventional histological staining was performed in order to detect inorganic matrix, cellular or organic matrix components. Allogeneic material-1 showed trabecular bone-like structures, which were free of cellular components as well as of organic matrix. The allogeneic material-2 showed trabecular bone structures, in which connective tissue and cellular remnants were embedded. Additionally, some connective tissue, which resembled fat-like tissue, was found within this material. The xenogeneic material-1 showed trabecular bone-like structures and contained organic com- ponents comparable to that demonstrated for the allogeneic material-2. The xenogeneic material-2 showed trabecular bone structures with single cells located in lacunae. The xenogeneic material-3 also showed trabecular structures. Neither cellular nor organic matrix components were found within this material. According to the data of the present study, the allogeneic material-1 and the xenogeneic material-3 were the only investigated materials for which the obtained histological data were in accordance with the manufacturer ´s advertised information. The remaining three materials showed discrepancies—although the manufacturers of all five bone substitute materials stated that their blocks were free of organic/cellular remnants. These data are of great clinical and material science interest. It seems that even patented processing techniques are not always able to deliver reproducible materials. Although the manufacturers of all five bone blocks stated that their blocks were free of organic/cellular remnants, our histological analysis revealed that three out of five bone blocks did contain such remnants. Such specimens might be able to induce an immune response within the recipient. Ó 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. 1. Introduction Regenerating and enlarging local bone volume frequently requires procedures involving either bone transplants or bone sub- stitute materials. Although still postulated as the gold standard [1], the use of autologous bone transplants is associated with several disadvantages including the need for a second surgical stage and the risk of donor site morbidity [2]. In the last decades, biomateri- als research and the related industry have developed a large number of different bone substitute materials, which all aim to avoid the need to use autologous bone transplants, either from the mouth or the iliac crest region. Among the possible sources for the bone substitute materials, human bone from deceased or living donors (allografts), as well as bone from different species (xenografts) have been proposed as reliable alternative concepts to autografts, when considering the biological performance of the grafts in patients [3–5]. However, organic residues within these ‘‘naturally derived’’ bone substitutes might contain pathogenic agents or genetic mate- rial and should therefore be thoroughly removed during the manufacturing process [6]. On the other hand, these materials should contain components such as extracellular bone matrix and tissue-specific collagen, which can support the natural bone http://dx.doi.org/10.1016/j.actbio.2014.04.017 1742-7061/Ó 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Department for Oral, Cranio-Maxillofacial and Facial Plastic Surgery, Medical Center of the Goethe University Frankfurt, Frankfurt am Main, Germany. Tel.: +49 69 6301 3744; fax: +49 69 6301 5644. E-mail address: shahram.ghanaati@kgu.de (S. Ghanaati). Acta Biomaterialia xxx (2014) xxx–xxx Contents lists available at ScienceDirect Acta Biomaterialia journal homepage: www.elsevier.com/locate/actabiomat Please cite this article in press as: Ghanaati S et al. Potential lack of ‘‘standardized’’ processing techniques for production of allogeneic and xenogeneic bone blocks for application in humans. Acta Biomater (2014), http://dx.doi.org/10.1016/j.actbio.2014.04.017