Surface treatment effects on amalgam repair strength.
OBJECTIVE
To determine whether the use of microetching and bonding agents could improve the shear bond strength between aged and freshly added dental amalgam, simulating an amalgam repair.


METHODS
Aged amalgam surfaces were treated with either a carbide bur or carbide bur + microetcher (Al2O3 abrasive). Five commercially-available adhesive systems were tested. Fresh amalgam was condensed through a split mold onto each prepared amalgam surface. Two control groups were included: a positive control consisting of non-repaired amalgam, and a negative control consisting of aged specimens which received neither carbide bur nor microetching preparation prior to the addition of fresh amalgam. In addition, one group received only carbide bur and another received only carbide bur and microetching treatments, without any adhesive. Following storage and thermocycling, each specimen was tested for shear bond strength.


RESULTS
The mean shear bond strength of the repaired samples treated with carbide bur alone (25.8 MPa) was not exceeded by any of the other treatments. Neither microetching nor use of an adhesive agent significantly improved amalgam-to-amalgam shear bond strength. In some cases, use of an adhesive agent significantly decreased the shear bond strength of repaired amalgam samples.
Diefenderfer
K E
KE
Naval Dental Research Institute, Naval Dental School, National Naval Dental Center, Bethesda, MD 20889-5602, USA.
Reinhardt
J W
JW
Brown
S B
SB
D000537:Aluminum Oxide; D000704:Analysis of Variance; D003188:Composite Resins; D019245:Compressive Strength; D003722:Dental Alloys; D003723:Dental Amalgam; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements; D003775:Dental Polishing; D005899:Glass Ionomer Cements; D008422:Materials Testing; D019563:Mechanics; D008689:Methacrylates; D008855:Microscopy, Electron, Scanning; D013718:Tensile Strength
C094366:Advance cement; C070606:Amalgambond; D003188:Composite Resins; D003722:Dental Alloys; D003738:Dental Cements; C113301:FujiPlus; D005899:Glass Ionomer Cements; D008689:Methacrylates; C110709:resinomer; C100742:All-Bond 2; C036886:tytin; D003723:Dental Amalgam; D000537:Aluminum Oxide