Fibrin clot adhesion to dentin conditioned with protein constructs: an in vitro proof-of-principle study.
OBJECTIVE
Periodontal regeneration is contingent on the adsorption, uninterrupted adhesion, and maturation of a fibrin clot to a periodontally compromised root surface. Clot adhesion appears vitally dependent on the formation of a resilient union between the clot and the root surface. Root surface demineralization will remove a root surface smear layer exposing dentin tubules and collagen matrix for enhanced clot adhesion. Recently, protein constructs have been introduced to condition the root during periodontal surgery. The effect of such root conditioning on clot adhesion has not been clarified. The objective of this study was to evaluate clot adhesion to protein conditioned dentin surfaces.


METHODS
Human dentin blocks (4 x 6 x 1 mm) were exposed to a saturated citric acid solution (CA) or a commercial ethylenediaminetetraacetic acid (EDTA) preparation using standardized protocols. Some dentin blocks were additionally conditioned with proteins, either bovine serum albumin (BSA) or an enamel matrix protein preparation (EMP). Fresh human whole blood was applied to the blocks. The blood was allowed to clot for 20 min. in a humidified chamber. The dentin blocks were rinsed 3 x 5 min. in phosphate-buffered saline under standardized conditions to test clot adhesion. They were then processed for scanning electron microscopy (SEM). Two masked examiners independently evaluated the SEM images.


RESULTS
CA removed the dentin smear layer, exposing dentin tubules and collagen. EDTA appeared less efficacious leaving smear layer residues. The BSA or EMP application resulted in a surface morphology similar to that of a smear layer. Fibrin clot adhesion was best supported by the CA-treated dentin surface. Forces produced by the rinse protocol partially removed the fibrin clot from EDTA-treated surfaces. BSA- or EMP-treated surfaces poorly retained the fibrin clot.


CONCLUSIONS
CA surface demineralization removes a dentin surface smear layer to promote adhesion of a fibrin clot. The EDTA gel appears less effective. Further conditioning of the dentin surface with protein constructs produces a surface morphology similar to that of the smear layer with poor fibrin clot retention.
Baker
David L
DL
Department of Dental Hygiene, University of New England, Portland, ME, USA. dbaker2@bates.edu
Stanley Pavlow
Sarah A
SA
Wikesjö
Ulf M E
UM
D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects*; D002417:Cattle; D002614:Chelating Agents / Q000494:pharmacology; D019343:Citric Acid / Q000494:pharmacology; D003746:Dental Enamel Proteins / Q000627:therapeutic use; D003804:Dentin / Q000187:drug effects*; D004492:Edetic Acid / Q000494:pharmacology; D005337:Fibrin / Q000187:drug effects*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D012710:Serum Albumin, Bovine / Q000627:therapeutic use; D016369:Smear Layer; D014092:Tooth Root / Q000187:drug effects*
D002614:Chelating Agents; D003746:Dental Enamel Proteins; C109069:enamel matrix proteins; D012710:Serum Albumin, Bovine; D019343:Citric Acid; D005337:Fibrin; D004492:Edetic Acid