title: Effects of light penetration and smear layer removal on adhesion of post-cores to root canal dentin by self-etching adhesives.
abstract: OBJECTIVE
  This study investigated the effects of light penetration and removal of smear layer on the adhesive properties of self-etching adhesives to root canal dentin when using fiber posts.
  
  
  METHODS
  Altogether 54 human incisors and premolars were decoronated, and the roots after preparing the post space were randomly assigned into six groups. Three groups were treated with a light-cured self-etching adhesive and the other three with a dual-cured self-etching adhesive. In a further sub-division, the first group was light-cured with an irradiation unit; the second was light-cured with the irradiation unit and a light-guiding attachment; and the third was light-cured with the irradiation unit and the attachment after removing smear layer by EDTA and NaOCl. Then, a glass-fiber post was luted into the post space by a dual-cured composite. After 24h, an hourglass-shaped specimen was trimmed and subjected to MTBS testing.
  
  
  RESULTS
  Using the light-guiding attachment and removing the smear layer reduced the incidence of pre-testing failure significantly from 57.1% to 19.0% (p<0.05) in the light-cured adhesive groups and from 68.3% to 3.2% (p<0.01) in the dual-cured adhesive groups. The MTBS in different locations within a post space were in the range from 8.9 to 17.5MPa in the light-cured group and from 11.2 to 17.2MPa in the dual-cured group.
  
  
  CONCLUSIONS
  Better light penetration in post spaces and removal of the smear layer are effective in improving the adhesive properties of self-etching adhesives to root canal dentin when using fiber posts.
authors.affiliation: Institute of Stomatology, Department of Operative Dentistry and Endodontology, College of Stomatology, Nanjing Medical University, Nanjing, China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Wu
authors.forename: Mikako
authors.initials: M
authors.lastname: Hayashi
authors.forename: Kenji
authors.initials: K
authors.lastname: Okamura
authors.forename: Evgeni V
authors.initials: EV
authors.lastname: Koytchev
authors.forename: Satoshi
authors.initials: S
authors.lastname: Imazato
authors.forename: Saori
authors.initials: S
authors.lastname: Tanaka
authors.forename: Yuko
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Sano
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Ebisu
mesh_terms: D002614:Chelating Agents / Q000627:therapeutic use; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000648:ultrastructure*; D019232:Dental Restoration Failure; D003804:Dentin / Q000187:drug effects / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry* / Q000528:radiation effects; D004492:Edetic Acid / Q000627:therapeutic use; D005898:Glass / Q000737:chemistry; D006801:Humans; D008027:Light; D008689:Methacrylates / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry / Q000528:radiation effects; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000379:methods; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D002614:Chelating Agents; C469237:Clearfil Core; C112274:Clearfil Liner Bond 2; C438313:Clearfil SE Bond; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; D012388:Root Canal Irrigants; C009753:fiberglass; D004492:Edetic Acid; D012973:Sodium Hypochlorite