Factors that affect the shear bond strength of multiple component and single bottle adhesives to dentin.
OBJECTIVE
To examine the effects of thermocycling and the long-term integrity of the bonds between adhesive and resin composite to bovine dentin using multi-step and single bottle adhesive systems.


METHODS
Dentin bonding sites were prepared using water irrigated #600 grit SiC paper on bovine incisor crowns mounted in acrylic resin. A 4 mm diameter area of dentin was etched, rinsed, left visibly moist and adhesives applied according to the manufacturers' instructions. The adhesives were: Scotchbond Multipurpose, Single Bond, All Bond 2, One Step, and Prime & Bond 2.1. Cylinders of Z100 resin composite 4 mm in diameter were positioned over the adhesive and visible light-cured. Bonded specimens were divided into five groups each containing 12 samples and: (1) stored in water for 24 hours; (2) stored in water for 7 days; (3) stored in water for 270 days; (4) thermocycled after 24 hours and stored for a total lapsed time of 7 days; (5) stored in water for 6.5 days, and thermocycled for a total lapsed time of 7 days. All storage temperatures were 37 degrees C. All specimens were shear (SBS) tested to failure at the end of each storage period, the results converted to MPa and the mode of fracture failure recorded.


RESULTS
The SBS for all five adhesives deteriorated over time; the effects of thermocycling were shown to be variable and dependant upon the adhesive; the modes of fracture failure were shown to be adhesive/cohesive or mixed; after long-term (270 days) storage there was an increased tendency for adhesive/cohesive fracture failure.
Titley
Keith
K
Department of Paediatric Dentistry, Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, Ontario, Canada, M5G 1G6. k.titley@utoronto.edu
Caldwell
Richard
R
Kulkarni
Gajanan
G
D000096:Acetone; D000704:Analysis of Variance; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate; D002417:Cattle; D001840:Dental Bonding / Q000379:methods*; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents; D016018:Least-Squares Analysis; D008422:Materials Testing; D008689:Methacrylates; D011109:Polymethacrylic Acids; D019279:Resin Cements; D033081:Shear Strength; D013997:Time Factors
C103506:Bis-GMA, BPDM, HEMA dental-bonding resin; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D011109:Polymethacrylic Acids; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C444444:prime and bond 2.1; C115612:single bond; D000096:Acetone; C100742:All-Bond 2; D017438:Bisphenol A-Glycidyl Methacrylate