title: Comparison among four commonly used demineralizing agents for root conditioning: a scanning electron microscopy.
abstract: Dental roots that have been exposed to the oral cavity and periodontal pocket environment present superficial changes, which can prevent connective tissue reattachment. Demineralizing agents have been used as an adjunct to the periodontal treatment aiming at restoring the biocompatibility of roots.
  
  
  OBJECTIVE
  This study compared four commonly used demineralizing agents for their capacity of removing smear layer and opening dentin tubules.
  
  
  METHODS
  Fifty fragments of human dental roots previously exposed to periodontal disease were scaled and randomly divided into the following groups of treatment: 1) CA: demineralization with citric acid for 3 min; 2) TC-HCl: demineralization with tetracycline-HCl for 3 min; 3) EDTA: demineralization with EDTA for 3 min; 4) PA: demineralization with 37% phosphoric acid for 3 min; 5) CONTROL: rubbing of saline solution for 3 min. Scanning electron microscopy was used to check for the presence of residual smear layer and for measuring the number and area of exposed dentin tubules.
  
  
  RESULTS
  Smear layer was present in 100% of the specimens from the groups PA and control; in 80% from EDTA group; in 33.3% from TC-HCl group and 0% from CA group. The mean numbers of exposed dentin tubules in a standardized area were: TC-HCl=43.8±25.2; CA=39.3±37; PA=12.1±16.3; EDTA=4.4±7.5 and CONTROL=2.3±5.7. The comparison showed significant differences between the following pairs of groups: TC-HCl and CONTROL; TC-HCl and EDTA; CA and CONTROL; and CA and EDTA. The mean percentages of area occupied by exposed dentin tubules were: CA=0.12±0.17%; TC-HCl=0.08±0.06%; PA=0.03±0.05%; EDTA=0.01±0.01% and CONTROL=0±0%. The CA group differed significantly from the others except for the TC-HCl group.
  
  
  CONCLUSIONS
  There was a decreasing ability for smear layer removal and dentin tubule widening as follows: AC>TC-HCl>PA>EDTA. This information can be of value as an extra parameter for choosing one of them for root conditioning.
authors: Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors: Nathalia Godoy do
authors: NG
authors: Amaral
authors: Maria Lúcia Rubo de
authors: ML
authors: Rezende
authors: Fabiana
authors: F
authors: Hirata
authors: Marcus Gustavo Silva
authors: MG
authors: Rodrigues
authors: Adriana Campos Passanezi
authors: AC
authors: Sant'ana
authors: Sebastião Luiz Aguiar
authors: SL
authors: Greghi
authors: Euloir
authors: E
authors: Passanezi
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000704:Analysis of Variance; D019343:Citric Acid / Q000494:pharmacology; D003737:Dental Cavity Preparation / Q000379:methods*; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D004492:Edetic Acid / Q000494:pharmacology; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000494:pharmacology; D016369:Smear Layer; D018709:Statistics, Nonparametric; D013499:Surface Properties / Q000187:drug effects; D013752:Tetracycline / Q000494:pharmacology; D013997:Time Factors; D014092:Tooth Root / Q000187:drug effects* / Q000648:ultrastructure
chemical_list: D010756:Phosphoric Acids; D019343:Citric Acid; D004492:Edetic Acid; C030242:phosphoric acid; D013752:Tetracycline