Microtensile bond strength of thermally stressed composite-dentin bonds mediated by one-bottle adhesives.
OBJECTIVE
To evaluate the effects of thermally stressing composite-dentin bonds in teeth subjected to a modified microtensile bond test that allowed application of two bonding agents side-by-side to the same tooth.


METHODS
Extracted human molars with a slot dissecting the occlusal dentin surface were conditioned and primed on one side with Prime & Bond NT (PBNT) and Prime One Mirage (P-One) on the other side. The composite was light-cured onto the surface. Approximately 0.5 mm thick dumbbell-shaped tensile specimens were tested after 24-hour water storage or after thermocycling 2400 times at 5 and 55 degrees C. Interfacial morphologies were evaluated by scanning electron microscopy (SEM).


RESULTS
Mean tensile bond strengths (TBS +/- standard deviation) were (36 +/- 24 MPa and 31 +/- 16 MPa) for PBNT, and (51 +/- 25 MPa and 40 +/- 18 MPa) for P-One without and with thermocycling, respectively. 97% of all tested specimens failed adhesively. Differences between the bonding systems and the therrmal treatments were significant (two-way ANOVA, P < 0.05). Regression analysis showed regional correlation between mean TBS of each bonding agent when grouped by the teeth from which they were obtained (r = 0.66, P = 0.002). SEM revealed that both bonding agents effectively wetted the conditioned dentin producing a typical hybrid layer, surface-textured resin tags with multiple lateral branches.
Xie
Baosheng
B
Paffenbarger Research Center, American Dental Association Health Foundation, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8546, USA.
Dickens
Sabine H
SH
Giuseppetti
Anthony A
AA
D000134:Acid Etching, Dental; D000268:Adhesiveness; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005240:Feasibility Studies; D006801:Humans; D008855:Microscopy, Electron, Scanning; D011109:Polymethacrylic Acids / Q000737:chemistry; D012044:Regression Analysis; D013314:Stress, Mechanical; D013499:Surface Properties; D013816:Thermodynamics; D013997:Time Factors; D014867:Water / Q000737:chemistry
D003188:Composite Resins; D017220:Dentin-Bonding Agents; D011109:Polymethacrylic Acids; C472326:Prime One Mirage; C425843:Prime and Bond NT; D014867:Water