title: Pore characteristics of bone substitute materials assessed by microcomputed tomography.
abstract: OBJECTIVE
  Pore configurations of alloplastic biomaterial scaffolds play a major role for new bone formation in vivo. Current studies on characteristics of pores in bone substitute materials focus on individual particles or single blocks. Thus, three-dimensional (3-D) architecture of particle aggregates, representing the clinical relevant in vivo situation is not adequately taken into account. The aim of this study was the visualization and quantification of pore properties, both of the scaffold structure of single particles as well as of the micro-morphology of complex 3-D aggregated particle-conglomerates.
  
  
  METHODS
  In model experiments, standardized plexiglass cylinders were stuffed with commercial bone substitute material particles with diverse chemical composition (HA, beta-TCP, HA-SiO(2), HA-beta-TCP, bioactive glass), origin (phycogenic, bovine, synthetic) and granulation (50 mum-2000 mum). Analogue to establish procedures for native (human) bone samples, non-fixed bone substitute materials were scanned by high-resolution microcomputed tomography. In addition to computer animated two-dimensional and 3-D reconstruction of the samples, median pore thickness and pore size distribution were determined. Materials representative for their chemical constitution were documented by SEM imaging.
  
  
  RESULTS
  Investigated specimens significantly were different in micro-morophology and pore properties, ranging from highly porous to rather solid. The most voluminous pores were localized interparticularly. Within one product line, the determined pore properties showed a significant correlation with single particle grain sizes.
  
  
  CONCLUSIONS
  The generation and interpretation of micro-CT based 3-D pore models can provide further insight into the expected osteoconduction dynamics and therefore might serve as a basis for further modifications of scaffold size and geometry as well as for further invasive studies on the biological behaviour of the scaffolds.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospital Mainz, Mainz, Germany. klein@mkg.klinik.uni-mainz.de
authors.forename: Marcus
authors.initials: M
authors.lastname: Klein
authors.forename: Hermann
authors.initials: H
authors.lastname: Goetz
authors.forename: Sabine
authors.initials: S
authors.lastname: Pazen
authors.forename: Bilal
authors.initials: B
authors.lastname: Al-Nawas
authors.forename: Wilfried
authors.initials: W
authors.lastname: Wagner
authors.forename: Heinz
authors.initials: H
authors.lastname: Duschner
mesh_terms: D000818:Animals; D001861:Bone Regeneration; D018786:Bone Substitutes / Q000737:chemistry; D002417:Cattle; D006801:Humans; D021621:Imaging, Three-Dimensional; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D016062:Porosity; D054457:Tissue Scaffolds; D055114:X-Ray Microtomography
chemical_list: D018786:Bone Substitutes