Interfacial ultrastructure of the resin-enamel region of three adhesive systems.
OBJECTIVE
To observe the resin/enamel interface produced by different adhesive systems.


METHODS
A conventional three-step smear layer removing adhesive system (Scotchbond Multi-Purpose), a two-step smear layer removing adhesive system (Prime & Bond), and a two-step smear layer dissolving adhesive system containing a self-etching primer (Panavia 21) were evaluated. Flat enamel surfaces were obtained from approximal surfaces of 18 extracted human molars. A total of 36 surfaces were collected and divided into three groups of 12 samples. One-half of each specimen in each group was etched with 35% phosphoric acid prior to the application of each adhesive system, with the second half being kept unetched. Subsequently, resin composite was placed and polymerized for 40 seconds. The samples were fractured and immersed into HCl and NaOCl solutions, followed by critical point drying and sputter coating for examination with a field emission scanning electron microscope.


RESULTS
In the etched samples, Panavia 21 and Scotchbond Multi-Purpose showed more consistent resin tag penetration than did Prime & Bond. Unetched Prime & Bond and Scotchbond Multi-Purpose samples showed minimal or no adhesive penetration in enamel surfaces.
Gordan
V V
VV
Department of Operative Dentistry, College of Dentistry, University of Florida Health Science Center, Gainesville 32610-0415, USA.
Vargas
M A
MA
Denehy
G E
GE
D000134:Acid Etching, Dental; D000269:Adhesives / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003743:Dental Enamel / Q000648:ultrastructure; D003745:Dental Enamel Permeability; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000737:chemistry; D010756:Phosphoric Acids; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry; D016369:Smear Layer; D013499:Surface Properties
D000269:Adhesives; D017220:Dentin-Bonding Agents; C093719:Panavia TPN-S; D010710:Phosphates; D010756:Phosphoric Acids; D011109:Polymethacrylic Acids; C103500:Prime & Bond; D019279:Resin Cements; D012117:Resins, Synthetic; C084018:Scotchbond Multi-Purpose; D017438:Bisphenol A-Glycidyl Methacrylate; C030242:phosphoric acid