title: Evaluation of the true self-etching potential of a fourth generation self-adhesive methacrylate resin-based sealer.
abstract: BACKGROUND
  The limited diffusion of self-adhesive resin cements into crown dentin raises doubts on whether self-adhesive root canal sealers are capable of creating micromechanical retention in instrumented canal walls in the absence of adjunctive use of calcium chelating irrigants. This study evaluated the true self-etching potential of MetaSEAL, a self-adhesive sealer.
  
  
  METHODS
  Mixed MetaSEAL sealer was applied to (1) fractured radicular dentin that was devoid of smear layers, (2) instrumented canal wall radicular dentin that was irrigated with water as the final rinse to preserve the smear layer, and (3) instrumented canal wall radicular dentin that was irrigated with ethylenediaminetetraacetic acid (EDTA) as the final rinse to remove the smear layer. Cryofractured tooth halves without sealer application were examined by scanning electron microscopy to identify the characteristics of the bonding substrates. The other tooth-halves were filled with sealer and processed for transmission electron microscopy.
  
  
  RESULTS
  MetaSEAL did not demineralize fractured radicular dentin that was devoid of smear layer and smear plugs. The self-adhesive sealer was incapable of etching beyond the 1- to 2-mum-thick smear layer retained on water-irrigated instrumented dentin to demineralize the underlying radicular dentin. Smear layer and smear plugs were absent in EDTA-irrigated radicular dentin. The EDTA also partially demineralized the intact dentin, creating a thin bed of collagen for infiltration of the self-adhesive sealer.
  
  
  CONCLUSIONS
  The limited self-etching potential of MetaSEAL is a clinically legitimate concern. Incomplete smear layer removal from instrumented canal wall regions that are not reached by calcium chelating agents might jeopardize its bonding and sealing performance.
authors.affiliation: Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China.
authors.forename: Sui
authors.initials: S
authors.lastname: Mai
authors.forename: Young Kyung
authors.initials: YK
authors.lastname: Kim
authors.forename: Noriko
authors.initials: N
authors.lastname: Hiraishi
authors.forename: Junqi
authors.initials: J
authors.lastname: Ling
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D002614:Chelating Agents; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods*; D003804:Dentin / Q000000981:diagnostic imaging; D017220:Dentin-Bonding Agents; D004492:Edetic Acid; D006801:Humans; D008689:Methacrylates; D008854:Microscopy, Electron; D019279:Resin Cements; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D016369:Smear Layer; D014463:Ultrasonography
chemical_list: D002614:Chelating Agents; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; C534239:metaseal; D004492:Edetic Acid