title: Improvement of enamel bond strengths for conventional and resin-modified glass ionomers: acid-etching vs. conditioning.
abstract: OBJECTIVE
  This study deals with the effect of phosphoric acid etching and conditioning on enamel micro-tensile bond strengths (μTBSs) of conventional and resin-modified glass ionomer cements (GICs/RMGICs).
  
  
  METHODS
  Forty-eight bovine incisors were prepared into rectangular blocks. Highly-polished labial enamel surfaces were either acid-etched, conditioned with liquids of cements, or not further treated (control). Subsequently, two matching pre-treated enamel surfaces were cemented together with one of four cements [two GICs: Fuji I (GC), Ketac Cem Easymix (3M ESPE); two RMGICs: Fuji Plus (GC), RelyX Luting (3M ESPE)] in preparation for μTBS tests. Pre-treated enamel surfaces and cement-enamel interfaces were analyzed by scanning electron microscopy (SEM).
  
  
  RESULTS
  Phosphoric acid etching significantly increased the enamel μTBS of GICs/RMGICs. Conditioning with the liquids of the cements produced significantly weaker or equivalent enamel μTBS compared to the control. Regardless of etching, RMGICs yielded stronger enamel μTBS than GICs. A visible hybrid layer was found at certain enamel-cement interfaces of the etched enamels.
  
  
  CONCLUSIONS
  Phosphoric acid etching significantly increased the enamel μTBSs of GICs/RMGICs. Phosphoric acid etching should be recommended to etch the enamel margins before the cementation of the prostheses such as inlays and onlays, using GICs/RMGICs to improve the bond strengths. RMGICs provided stronger enamel bond strength than GICs and conditioning did not increase enamel bond strength.
authors.affiliation: Hospital of Stomatology Affiliated to Zhejiang University School of Medicine, Hangzhou 310006, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Tian
authors.initials: T
authors.lastname: Tang
authors.forename: Zhen-liang
authors.initials: ZL
authors.lastname: Zhang
authors.forename: Bing
authors.initials: B
authors.lastname: Liang
authors.forename: Xiao-miao
authors.initials: XM
authors.lastname: Wang
authors.forename: Bai-ping
authors.initials: BP
authors.lastname: Fu
mesh_terms: D000134:Acid Etching, Dental; D000818:Animals; D002417:Cattle; D003743:Dental Enamel; D005899:Glass Ionomer Cements; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids; D013718:Tensile Strength
chemical_list: D005899:Glass Ionomer Cements; D010756:Phosphoric Acids; C030242:phosphoric acid