title: The physical characteristics of resin composite-calcium silicate interface as part of a layered/laminate adhesive restoration.
abstract: OBJECTIVE
  To compare in-vitro micro-shear bond strengths (μSBS) of resin composite to calcium silicate cement (Biodentine™) vs. glass ionomer cement vs. resin modified glass ionomer cement (RM-GIC) using an adhesive in self-etch (SE)/total etch (TE) mode after aging three substrates and bond and characterizing their failure modes.
  
  
  METHODS
  Resin composite was SE/TE bonded to 920 standardized disks of Biodentine™, GIC & RM-GIC. Dividing samples into two groups, the first underwent early (t=0min, 5min, 20min, 24h) or delayed (t=2wk, 1 month, 3 months, 6 months) substrate aging before bonding and μSBS (t=24h) testing. In the second, adhesive was applied after either early (t=5min) or delayed (t=2wk) substrate aging and then tested after bond aging (t=2wk, 1 month, 3 months, 6 months). The failure modes were identified using stereomicroscope. SEM images of selected samples were analyzed.
  
  
  RESULTS
  No significant differences were observed between (SE)/(TE) bonding modes (P=0.42). With substrate aging, a significant reduction in μSBS occurred between early and delayed time intervals for Biodentine™ (P=0.001), but none for the GIC/RM-GIC (P=0.465, P=0.512 respectively). With bond aging, there was no significant difference between time intervals for all groups, except at 6 months for the GIC (P<0.05). Modes of failure were primarily cohesive within all the substrates (68.82%) followed by adhesive failure at the resin-substrate interface (21.71%).
  
  
  CONCLUSIONS
  Biodentine™ is a weak restorative material in its early setting phase. Placing the overlying resin composite as part of the laminate/layered definitive restoration is best delayed for >2wk to allow sufficient intrinsic maturation to withstand contraction forces from the resin composite. A total-etch or self-etch adhesive may be used.
authors.affiliation: Unit of Conservative Dentistry, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK; Unit of Biomaterials, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK. Electronic address: danya.hashem@kcl.ac.uk.
authors.forename: Danya F
authors.initials: DF
authors.lastname: Hashem
authors.affiliation: Unit of Conservative Dentistry, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Foxton
authors.affiliation: Biostatistics & Research Methods Centre, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK.
authors.forename: Andiappan
authors.initials: A
authors.lastname: Manoharan
authors.affiliation: Unit of Conservative Dentistry, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK; Unit of Biomaterials, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK.
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Watson
authors.affiliation: Unit of Conservative Dentistry, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK; Unit of Biomaterials, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK.
authors.forename: Avijit
authors.initials: A
authors.lastname: Banerjee
mesh_terms: D000134:Acid Etching, Dental; D017610:Calcium Compounds / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D033081:Shear Strength; D017640:Silicates / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D017610:Calcium Compounds; D003188:Composite Resins; D003738:Dental Cements; D005899:Glass Ionomer Cements; D017640:Silicates; C506393:tricalcium silicate; C031293:calcium silicate
keywords: Adhesive; Biodentin; Calcium silicate cement; Dentin bonding agent; Failure mode; Glass ionomer cement; Micro-shear bond strength; Resin-modified glass ionomer cement; SEM