title: Comparison of the capacity of enamel matrix derivative gel and enamel matrix derivative in liquid formulation to adsorb to bone grafting materials.
abstract: BACKGROUND
  The use of an enamel matrix derivative (EMD) has been shown to enhance periodontal regeneration (e.g., formation of root cementum, periodontal ligament, and alveolar bone). However, in certain clinical situations, the use of EMD alone may not be sufficient to prevent flap collapse or provide sufficient stability of the blood clot. Data from clinical and preclinical studies have demonstrated controversial results after application of EMD combined with different types of bone grafting materials in periodontal regenerative procedures. The aim of the present study is to investigate the adsorption properties of enamel matrix proteins to bone grafts after surface coating with either EMD (as a liquid formulation) or EMD (as a gel formulation).
  
  
  METHODS
  Three different types of grafting materials, including a natural bone mineral (NBM), demineralized freeze-dried bone allograft (DFDBA), or a calcium phosphate (CaP), were coated with either EMD liquid or EMD gel. Samples were analyzed by scanning electron microscopy or transmission electron microscopy (TEM) using an immunostaining assay with gold-conjugated anti-EMD antibody. Total protein adsorption to bone grafting material was quantified using an enzyme-linked immunosorbent assay (ELISA) kit for amelogenin.
  
  
  RESULTS
  The adsorption of amelogenin to the surface of grafting material varied substantially based on the carrier system used. EMD gel adsorbed less protein to the surface of grafting particles, which easily dissociated from the graft surface after phosphate-buffered saline rinsing. Analyses by TEM revealed that adsorption of amelogenin proteins were significantly farther from the grafting material surface, likely a result of the thick polyglycolic acid gel carrier. ELISA protein quantification assay demonstrated that the combination of EMD liquid + NBM and EMD liquid + DFDBA adsorbed higher amounts of amelogenin than all other treatment modalities. Furthermore, amelogenin proteins delivered by EMD liquid were able to penetrate the porous surface structure of NBM and DFDBA and adsorb to the interior of bone grafting particles. Grafting materials coated with EMD gel adsorbed more frequently to the exterior of grafting particles with little interior penetration.
  
  
  CONCLUSIONS
  The present study demonstrates a large variability of adsorbed amelogenin to the surface of bone grafting materials when enamel matrix proteins were delivered in either a liquid formulation or gel carrier. Furthermore, differences in amelogenin adsorption were observed among NBM, DFDBA, and biphasic CaP particles. Thus, the potential for a liquid carrier system for EMD, used to coat EMD, may be advantageous for better surface coating.
authors.affiliation: School of Dental Medicine, University of Laval, Quebec City, QC.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Miron
authors.forename: Dieter D
authors.initials: DD
authors.lastname: Bosshardt
authors.forename: Daniel
authors.initials: D
authors.lastname: Buser
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Stefano
authors.initials: S
authors.lastname: Tugulu
authors.forename: Anja
authors.initials: A
authors.lastname: Gemperli
authors.forename: Michel
authors.initials: M
authors.lastname: Dard
authors.forename: Oana M
authors.initials: OM
authors.lastname: Caluseru
authors.forename: Fatiha
authors.initials: F
authors.lastname: Chandad
authors.forename: Anton
authors.initials: A
authors.lastname: Sculean
mesh_terms: D000327:Adsorption; D064591:Allografts / Q000737:chemistry; D053523:Amelogenin / Q000737:chemistry; D018786:Bone Substitutes / Q000737:chemistry*; D001842:Bone and Bones / Q000737:chemistry* / Q000648:ultrastructure; D002130:Calcium Phosphates / Q000737:chemistry; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003746:Dental Enamel Proteins / Q000737:chemistry* / Q000648:ultrastructure; D004337:Drug Carriers; D005782:Gels; D006801:Humans; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010539:Permeability; D011100:Polyglycolic Acid / Q000737:chemistry; D016062:Porosity; D012996:Solutions; D013499:Surface Properties
chemical_list: D053523:Amelogenin; D018786:Bone Substitutes; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D003746:Dental Enamel Proteins; D004337:Drug Carriers; D005782:Gels; D012996:Solutions; C109069:enamel matrix proteins; D011100:Polyglycolic Acid; C020243:calcium phosphate
keywords: Biphasic calcium phosphate; bone graft adsorption; bone transplantation; enamel matrix proteins; osseoinduction; osseoinductive