title: Dentin-like tissue formation and biomineralization by multicellular human pulp cell spheres in vitro.
abstract: BACKGROUND
  Maintaining or regenerating a vital pulp is a preferable goal in current endodontic research. In this study, human dental pulp cell aggregates (spheres) were applied onto bovine and human root canal models to evaluate their potential use as pre-differentiated tissue units for dental pulp tissue regeneration.
  
  
  METHODS
  Human dental pulp cells (DPC) were derived from wisdom teeth, cultivated into three-dimensional cell spheres and seeded onto bovine and into human root canals. Sphere formation, tissue-like and mineralization properties as well as growth behavior of cells on dentin structure were evaluated by light microscopy (LM), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).
  
  
  RESULTS
  Spheres and outgrown cells showed tissue-like properties, the ability to merge with other cell spheres and extra cellular matrix formation; CLSM investigation revealed a dense network of actin and focal adhesion contacts (FAC) inside the spheres and a pronounced actin structure of cells outgrown from the spheres. A dentin-structure-orientated migration of the cells was shown by SEM investigation. Besides the direct extension of the cells into dentinal tubules, the coverage of the tubular walls with cell matrix was detected. Moreover, an emulation of dentin-like structures with tubuli-like and biomineral formation was detected by SEM- and EDX-investigation.
  
  
  CONCLUSIONS
  The results of the present study show tissue-like behavior, the replication of tubular structures and the mineralization of human dental pulp spheres when colonized on root dentin. The application of cells in form of pulp spheres on root dentin reveals their beneficial potential for dental tissue regeneration.
authors.affiliation: Technische Universität Dresden, Institute of Material Science, Chair for Biomaterials, Budapester Strasse 27, D-01069 Dresden, Germany. joerg.neunzehn@tu-dresden.de.
authors.forename: Jörg
authors.initials: J
authors.lastname: Neunzehn
authors.forename: Marie-Theres
authors.initials: MT
authors.lastname: Weber
authors.forename: Gretel
authors.initials: G
authors.lastname: Wittenburg
authors.forename: Günter
authors.initials: G
authors.lastname: Lauer
authors.forename: Christian
authors.initials: C
authors.lastname: Hannig
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Wiesmann
mesh_terms: D018929:Cell Culture Techniques; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology* / Q000648:ultrastructure; D003804:Dentin / Q000502:physiology; D006801:Humans; D018613:Microscopy, Confocal; D013052:Spectrometry, X-Ray Emission; D023822:Tissue Engineering; D054457:Tissue Scaffolds