A study of bond strength of dentin bonding agents to human dentin.
BACKGROUND
Marginal leakage of restoration induced by polymerization shrinkage of composite resin can be prevented if the dentin bonding agent is strong enough to counteract the force of polymerization shrinkage.


METHODS
Fifty molar teeth obtained due to periodontal problem were used in this investigation. Crown portion of the teeth was grounded perpendicular to the long axis of the teeth until a complete layer of dentin surrounded by enamel was created. The teeth were then mounted with dental stone, and divided into five groups randomly. Dentin bonding agent was applied to the dentinal surface and a gelatin capsule mold was used to apply composite resin material. After incubation, the bonded composite specimens were tested with Instron universal testing machine in order to determine the shear strength of the composite bonding result. The fracture patterns were examined with scanning electron microscope.


RESULTS
The Universal bond 3 combined with the AP.H composite exhibited the highest shear bond strength (10.76 MPa). The fracture pattern of the Universal Bond 3 combined with AP.H was mainly that of cohesive failure in the composite resin part instead of adhesive failure in the other groups tested.


CONCLUSIONS
The shear bond strength of these five dentin bonding agents ranged from 2.89MPa to 10.76MPa. The fracture pattern of the tested groups was mainly that of adhesive failure at the interface between dentin bonding agent and its corresponding composite resin instead of cohesive failure disclosed in the composite resin part of Universal Bond 3 combined with AP.H group.
Dental Department, Veterans General Hospital-Taipei, Taiwan, R.O.C.
K W
KW
Chan
T H
TH
Lin
C C
CC
Chan
K H
KH
Chung
D001696:Biomechanical Phenomena; D003188:Composite Resins; D003804:Dentin; D017220:Dentin-Bonding Agents / Q000494:pharmacology*; D005069:Evaluation Studies as Topic; D006801:Humans; D066298:In Vitro Techniques; D008963:Molar; D014082:Tooth Fractures
D003188:Composite Resins; D017220:Dentin-Bonding Agents