title: [Effect of fluorided etching fluid on the shear bond strength and the deposition on the surface of enamel.].
abstract: OBJECTIVE
  The aim of this study was to find the best concentration of fluorided etching acid in the dental clinic which had both the best shear bond strength and the maximal anti-caries effect.
  
  
  METHODS
  84 extracted human premolars were divided into four groups of 21 teeth each. The enamel of each group was conditioned with 35% phosphoric acid containing 0%, 1.23%, 2%, 3% NaF. The shear bond strength was tested by bond strength machine and the enamel morphology was observed by scanning electron microscopy at once, 1 week, 4 weeks, 12 weeks, 24 weeks after etching. The shear bond strength was statistically analyzed by SPSS10.0 software.
  
  
  RESULTS
  The shear bond strength of the group whose acid containing 3% NaF was less than the others significantly (P<0.05); and there was no significant difference among the other groups (P>0.05). The amount of the deposition on the surface of enamel after etching was increased with the time after etching and the concentration of NaF increasing.
  
  
  CONCLUSIONS
  2% NaF added to 35% phosphoric acid has both the best bond strength and the best effect of preventing enamel from caries.
authors.affiliation: College of Stomatology, China Medical University, Shengyang 110002, China. xzf7090@yahool.com.cn.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Cui-Juan
authors.initials: CJ
authors.lastname: Feng
authors.forename: Jia
authors.initials: J
authors.lastname: Ma
authors.forename: Yu-Hua
authors.initials: YH
authors.lastname: Hong
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D001641:Bicuspid; D001840:Dental Bonding / Q000379:methods; D003743:Dental Enamel; D003799:Dental Stress Analysis; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements; D033081:Shear Strength
chemical_list: D010756:Phosphoric Acids; D019279:Resin Cements; C030242:phosphoric acid