title: Effects of citric acid and EDTA conditioning on exposed root dentin: An immunohistochemical analysis of collagen and proteoglycans.
abstract: OBJECTIVE
  Preservation of structural and biochemical properties of the root dentin matrix is crucial to favor healing and regenerative periodontal processes. Aim of this study was to evaluate the biochemical characteristics of collagen and chondroitin sulphate of root dentin surfaces exposed by periodontal disease after acid conditioning by means of an immunohistochemical technique.
  
  
  METHODS
  Human teeth scheduled for extraction due to periodontal reason were submitted to: (A) scaling and root planning; (B) ultrasonic instrumentation; (C) no instrumentation. Teeth were then exposed to: (1) 10% citric acid; (2) 17% EDTA; (3) no etching. A double immunolabeling technique was performed to identify type-I collagen and proteoglycans and analyzed under FEI-SEM.
  
  
  RESULTS
  Use of 10% citric acid revealed intense labeling for collagen fibrils and proteoglycans; lower labeling was found after EDTA conditioning. Unetched specimens showed residual smear layer on the dentin surface resulting in no evident surface labeling.
  
  
  CONCLUSIONS
  This study supports the hypothesis that manual or ultrasonic instrumentation alone is not able to expose the sound dentin matrix, whereas a subsequent acidic conditioning exposes collagen fibrils and associated proteoglycans. The immunohistochemical technique revealed that despite their acidity, both citric acid and EDTA were able to preserve the structural and biochemical properties of the exposed dentin matrix.
authors.affiliation: Department of SAU & FAL, University of Bologna, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Ruggeri
authors.forename: Carlo
authors.initials: C
authors.lastname: Prati
authors.forename: Annalisa
authors.initials: A
authors.lastname: Mazzoni
authors.forename: Cesare
authors.initials: C
authors.lastname: Nucci
authors.forename: Roberto
authors.initials: R
authors.lastname: Di Lenarda
authors.forename: Giovanni
authors.initials: G
authors.lastname: Mazzotti
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Breschi
mesh_terms: D000134:Acid Etching, Dental; D002614:Chelating Agents / Q000494:pharmacology*; D002809:Chondroitin Sulfates / Q000378:metabolism; D019343:Citric Acid / Q000494:pharmacology*; D003094:Collagen / Q000378:metabolism; D003804:Dentin / Q000187:drug effects*; D004492:Edetic Acid / Q000494:pharmacology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007150:Immunohistochemistry / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods; D011509:Proteoglycans / Q000378:metabolism; D014092:Tooth Root / Q000187:drug effects* / Q000648:ultrastructure; D014465:Ultrasonics
chemical_list: D002614:Chelating Agents; D011509:Proteoglycans; D019343:Citric Acid; D002809:Chondroitin Sulfates; D003094:Collagen; D004492:Edetic Acid