title: Morphological Evaluation of the Adhesive/Enamel interfaces of Two-step Self-etching Adhesives and Multimode One-bottle Self-etching Adhesives.
abstract: OBJECTIVE
  To evaluate the acid-base resistant zone (ABRZ) at the adhesive/enamel interface of self-etching adhesives with or without prior phosphoric acid etching.
  
  
  METHODS
  Four adhesives were used in 8 groups: Clearfil SE Bond (SEB), Optibond XTR (XTR), Scotchbond Universal Adhesive (SBU), and Clearfil BOND SE ONE (ONE) without prior phosphoric-acid etching, and each adhesive with phosphoric acid etching for 10 s (P-SEB, P-XTR, P-SBU and P-ONE, respectively). After application of self-etching adhesives on ground enamel surfaces of human teeth, a flowable composite was placed. For observation of the acid-base resistant zone (ABRZ), the bonded interface was exposed to demineralizing solution (pH 4.5) for 4.5 h, followed by 5% NaOCl with ultrasonication for 20 min. After the acid-base challenge, morphological attributes of the interface were observed using SEM.
  
  
  RESULTS
  ABRZ formation was confirmed in all groups. The funnel-shaped erosion beneath the interface was present in SBU and ONE, where nearly 10 to 15 μm of enamel was dissolved. With phosphoric acid etching, the ABRZs were obviously thicker compared with no phosphoric acid etching.
  
  
  CONCLUSIONS
  Enamel beneath the bonding interface was more susceptible to acid dissolution in SBU and ONE. In the case of the one-bottle self-etching adhesives and universal adhesives that intrinsically have higher pH values, enamel etching should be recommended to improve the interfacial quality.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Sato
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Takagaki
authors.forename: Naoko
authors.initials: N
authors.lastname: Matsui
authors.forename: Hidenori
authors.initials: H
authors.lastname: Hamba
authors.forename: Alireza
authors.initials: A
authors.lastname: Sadr
authors.forename: Toru
authors.initials: T
authors.lastname: Nikaido
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000134:Acid Etching, Dental / Q000379:methods*; D003188:Composite Resins / Q000737:chemistry; D003743:Dental Enamel / Q000648:ultrastructure*; D003747:Dental Enamel Solubility; D003764:Dental Materials / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000737:chemistry; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D012973:Sodium Hypochlorite / Q000737:chemistry; D013499:Surface Properties
chemical_list: C029849:Clearfil Bonding Agent; C438313:Clearfil SE Bond; D003188:Composite Resins; D003764:Dental Materials; C092987:Optibond; D010756:Phosphoric Acids; D019279:Resin Cements; C541508:clearfil majesty; C041330:Scotchbond; D012973:Sodium Hypochlorite; C030242:phosphoric acid; D019342:Acetic Acid