title: SEM evaluation of the resin-dentin interface with proprietary bonding agents in human subjects.
abstract: Laboratory studies on dentin bonding do not replicate physiological reality. This study examined with SEM the attachment produced in vivo under clinical conditions. Forty-four cavities were prepared in buccal/lingual surfaces of 16 premolar teeth scheduled for extraction and assigned randomly for treatment with: All-Bond 2 (Bisco) (A) with and (B) without dentin etch, (C) Scotchbond 2 (3M), (D) Scotchbond Multi-Purpose (3M), and (E) controls, using Enamel Bond (Kulzer) with dentin etch. After atraumatic extraction, restorations were split transversely by freeze-fracture and acid-treated. SEM examination of A revealed significant areas of gap-free attachment, with evidence of an acid-resistant hybrid layer (5-8 microns), often with resin tags of various lengths. Resin-reinforced collagen fibers were seen. Gap formation was coincident with lack of bonding resin layer over primed dentin. Attachment with B was less effective; a hybrid layer was infrequently seen and few resin tags. Pooled bonding resin at internal line angles appeared to favor an effective bond. Treatment C resulted in large areas of detachment, leaving an adherent primed dentin layer with short resin tags. Treatment D revealed significant areas of gap-free attachment and evidence of a hybrid layer. Controls (E) showed total bond failure. Attachment with A and D was secure, restorations remaining in situ even after freeze-fracture. This study confirmed that brief acid pre-treatment of dentin, allowing diffusion of resin-dentin primers, appeared conductive to development of an effective bond in vivo, similar to that reported in vitro.
authors.affiliation: Restorative Department, Faculty of Dentistry, University of Toronto, Ontario, Canada.
authors.forename: P R
authors.initials: PR
authors.lastname: Walshaw
authors.forename: D
authors.initials: D
authors.lastname: McComb
mesh_terms: D000134:Acid Etching, Dental; D000328:Adult; D003094:Collagen / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry* / Q000493:pharmacokinetics; D003804:Dentin / Q000378:metabolism / Q000648:ultrastructure*; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005614:Freeze Fracturing; D006801:Humans; D008689:Methacrylates; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements; D016369:Smear Layer; D013499:Surface Properties
chemical_list: C074864:All-Bond system; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C067788:scotchbond 2; D003094:Collagen