title: Polymerized bonding agents and the differentiation in vitro of human pulp cells into odontoblast-like cells.
abstract: OBJECTIVE
  Odontoblasts are highly differentiated post-mitotic cells, which under pathological conditions such as carious lesions and dental injuries may degenerate and be replaced by other pulp cells. We have recently shown that this physiological event can be reproduced in an in vitro assay system, but is highly modified by the presence of unpolymerized resinous monomers. Our hypothesis was that the photopolymerization of the monomers in the bonding agents might abolish these negative effects. The purpose of this study was to evaluate the effects of polymerized dentin bonding agents, through dentin slices, on odontoblast differentiation in vitro.
  
  
  METHODS
  Pulp cells were obtained from human third molars. They were used to study the effects of four dentin bonding agents through 0.7 mm dentin slices which served as a barrier between the bonding agents and the culture medium. The media containing the bonding agents' extracts were added at non-toxic concentrations onto the cultured cells. Immunohistochemistry was performed to study the differentiation of pulp fibroblasts into odontoblasts under these conditions by evaluating the expression of several odontoblast specific genes.
  
  
  RESULTS
  Pulp fibroblasts cultivated under these conditions synthesized type I collagen, osteonectin, dentin sialoprotein and nestin at the same level as in control cultures. Moreover, pulp cells synthesized a mineralized nodular extracellular matrix. Expression of these proteins was higher in the cells contributing to the nodule formation. In addition, except nestin, all these proteins were expressed in the mineral nodules.
  
  
  CONCLUSIONS
  This work shows the lack of effects of photopolymerized bonding agents, through dentin slices, on cytodifferentiation of secondary odontoblasts.
authors.affiliation: Laboratoire IMEB, Faculté d'Odontologie, Université de la Méditerranée, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 5, France. imad.about@odontologie.univ-mrs.fr
authors.forename: Imad
authors.initials: I
authors.lastname: About
authors.forename: Jean
authors.initials: J
authors.lastname: Camps
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Burger
authors.forename: Thimios A
authors.initials: TA
authors.lastname: Mitsiadis
authors.forename: William T
authors.initials: WT
authors.lastname: Butler
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Franquin
mesh_terms: D000293:Adolescent; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000096:biosynthesis; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects*; D003804:Dentin; D017220:Dentin-Bonding Agents / Q000494:pharmacology*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007381:Intermediate Filament Proteins / Q000096:biosynthesis; D008689:Methacrylates / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D064231:Nestin; D009804:Odontoblasts / Q000187:drug effects* / Q000378:metabolism; D015676:Osteonectin / Q000096:biosynthesis; D010750:Phosphoproteins; D011108:Polymers / Q000494:pharmacology; D011109:Polymethacrylic Acids / Q000494:pharmacology; D019279:Resin Cements / Q000494:pharmacology; D012795:Sialoglycoproteins / Q000096:biosynthesis; D000099311:Dentin Sialophosphoprotein
chemical_list: D024042:Collagen Type I; D017220:Dentin-Bonding Agents; D016326:Extracellular Matrix Proteins; D007381:Intermediate Filament Proteins; D008689:Methacrylates; D009419:Nerve Tissue Proteins; D064231:Nestin; D015676:Osteonectin; D010750:Phosphoproteins; D011108:Polymers; D011109:Polymethacrylic Acids; D019279:Resin Cements; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C103506:Bis-GMA, BPDM, HEMA dental-bonding resin; C577484:NES protein, human; C425843:Prime and Bond NT; C407402:Unifil Bond; C041330:Scotchbond