title: Micro-tensile bond testing of resin cements to dentin and an indirect resin composite.
abstract: OBJECTIVE
  Micro-tensile bond strength (microTBS) evaluation and fractographic analysis were used to compare four resin cement systems (AC: All-Bond 2/Choice; RX: Single Bond/RelyX ARC; SB: Super-Bond C & B; and PF: Panavia F) in indirect composite/dentin adhesive joints.
  
  
  METHODS
  Flat dentin surfaces were created on extracted human third molars. The resin cements were used according to the manufacturers' instructions for bonding silanized composite overlays to deep coronal dentin. 0.9x0.9 composite-dentin beams prepared from the luted specimens were stressed to failure in tension. Dentin sides of all fractured specimens were examined by scanning electron microscopy (SEM) to examine the failure modes. In group PF, morphologic features that could not be resolved at the SEM level were further validated by transmission electron microscopy (TEM) examination of the SEM specimens.
  
  
  RESULTS
  Statistical analyses revealed significant difference (p<0.05) among microTBS and failure modes in the resin cement groups. The two groups (AC and RX) with highest microTBS failed predominantly along the composite overlay/cement interface. Cohesive failure in resin cement was primarily observed in group SB that exhibited intermediate microTBS values. In group PF with the lowest microTBS, failure occurred mostly along the dentin surface. Globular resin agglomerates seen by SEM on PF-treated dentin were distinguished from silica fillers by TEM.
  
  
  CONCLUSIONS
  The bond between the processed composite and the luting resin cement was the weak link in indirect composite restorations cemented with AC or RX. Super-Bond C&B exhibited intermediate tensile strength and Panavia F is less reliable when used in conjunction with a self-etching primer for bonding indirect restorations to dentin.
authors.affiliation: Conservative Dentistry, Faculty of Dentistry, University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, SAR, Hong Kong, People's Republic of China.
authors.forename: Yiu-Fai
authors.initials: YF
authors.lastname: Mak
authors.forename: Shirley C N
authors.initials: SC
authors.lastname: Lai
authors.forename: Gary S P
authors.initials: GS
authors.lastname: Cheung
authors.forename: Alex W K
authors.initials: AW
authors.lastname: Chan
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate; D001896:Boron Compounds; D003188:Composite Resins; D001840:Dental Bonding; D003799:Dental Stress Analysis; D003804:Dentin; D017220:Dentin-Bonding Agents; D006801:Humans; D007284:Inlays; D008422:Materials Testing; D008689:Methacrylates; D008768:Methylmethacrylates; D008854:Microscopy, Electron; D011092:Polyethylene Glycols; D011109:Polymethacrylic Acids; D019279:Resin Cements; D018709:Statistics, Nonparametric; D013718:Tensile Strength
chemical_list: D001896:Boron Compounds; C086628:Choice resin cement; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D008768:Methylmethacrylates; C438843:Panavia-Fluoro; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; C115612:single bond; C100742:All-Bond 2; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C049495:Super-bond