title: Smear layer removal for collagen fiber exposure after citric acid conditionings.
abstract: OBJECTIVE
  The aim of the present study was to compare the removal of the smear layer and exposure of collagen fibers of the root surface following the application of five citric acid solution concentrations.
  
  
  METHODS
  Two hundred seventy (270) samples were equally divided into six groups (n=45) for treatment with saline solution (control) and five different concentrations of citric acid (0.5, 1, 2, 15, and 25 percent). Three acid application methods were used (passive, brushing, and burnishing) as well as three application periods (1, 2, and 3 minutes). A previously trained, calibrated (kappa score = 0.93), and blind examiner subsequently scored scanning electron micrographs (SEMs) of the samples. Statistical analyses were performed by using Kruskal-Wallis and Dunn's post-hoc tests.
  
  
  RESULTS
  According to the results obtained and within the limitations of the methodology used, the citric acid applications were more effective than the control treatment of applying saline solution (p<0.05). However, no statistically significant differences were observed among the three application methods and three application periods. Descriptive analyses showed that best results for exposure of collagen fibers were obtained with the application of citric acid at 25 percent by brushing for 1 or 3 minutes.
  
  
  CONCLUSIONS
  The best results for exposure of collagen fibers in this study were obtained with application of citric acid at 25 percent by brushing for 1 or 3 minutes, even though there were no statistically significant differences among the groups.
  
  
  CONCLUSIONS
  The best results for exposure of collagen fibers on root surfaces noted in this study were obtained with application of citric acid at 25 percent by brushing for 1 or 3 minutes.
authors.affiliation: Department of Diagnostics and Surgery, School of Dentistry at Araraquara, São Paulo State University, UNESP, São Paulo, Brazil. rcavassim@yahoo.com.br
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Cavassim
authors.forename: Fábio Renato Manzolli
authors.initials: FR
authors.lastname: Leite
authors.forename: Daniela Leal
authors.initials: DL
authors.lastname: Zandim
authors.forename: Andrea Abi Rached
authors.initials: AA
authors.lastname: Dantas
authors.forename: José Eduardo Cezar
authors.initials: JE
authors.lastname: Sampaio
mesh_terms: D019343:Citric Acid / Q000008:administration & dosage*; D003094:Collagen / Q000648:ultrastructure*; D012534:Dental Scaling / Q000379:methods; D003804:Dentin / Q000648:ultrastructure*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D057747:Periodontal Debridement / Q000295:instrumentation / Q000379:methods*; D016745:Root Planing / Q000379:methods; D016037:Single-Blind Method; D016369:Smear Layer; D012965:Sodium Chloride / Q000008:administration & dosage; D013997:Time Factors; D014092:Tooth Root / Q000648:ultrastructure*
chemical_list: D019343:Citric Acid; D012965:Sodium Chloride; D003094:Collagen