Resistance to thermo-mechanical stress of different coupling agents used as intermediate layer in resin-fiber post bonds.
OBJECTIVE
To evaluate the microtensile bond strength (MTBS) of different coupling agents used in fiber post-composite bonds to withstand different in vitro challenging procedures.


METHODS
63 fiber posts (DT Light Post) etched with 10% hydrogen peroxide were divided into three groups according to the silane/adhesive system applied: (1) Porcelain Bond Activator (PBA) + Clearfil SE Bond; (2) PBA + Clearfil Tri S Bond; (3) Monobond-S. A composite build-up (Clearfil AP-X) was performed around the post producing cylindrical specimens that were divided into three subgroups according to the different aging protocol: (1) 24-hour storage at room temperature; (2) Thermocycling (5000 cycles, 5 degrees/55 degrees C dwell time: 30 seconds); (3) Cyclic loading (45 degrees angle, 20,000 cycles, load 5-50 N at 3.0 Hz). Samples were then cut obtaining sticks that were loaded in tension until failure. Bond strength values were statistically analyzed with two-way ANOVA and Tukey test (alpha = 0.05). Failure mode was recorded and the morphologic aspect of post/core interface after aging was evaluated under SEM.


RESULTS
Both post superficial treatment, thermocycling and cyclic loading influenced bond strength. After 24 hours, samples treated with silane/adhesive couplings attained higher MTBS than those bonded with conventional silane. No significant differences in the microtensile bond strength at the post/core interface were recorded between the different silane/adhesive couplings. After challenging, no differences were found between the tested groups.
Monticelli
Francesca
F
Department of Dental Materials, School of Dentistry, University of Granada, Spain. francescamonti@hotmail.it
Osorio
Raquel
R
Tay
Franklin R
FR
Sadek
Fernanda T
FT
Ferrari
Marco
M
Toledano
Manuel
M
D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry*; D045662:Dental Etching / Q000379:methods; D019232:Dental Restoration Failure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D004853:Epoxy Resins / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D016877:Oxidants / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation*; D011791:Quartz / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors
C112828:Clearfil AP-X; C076805:Clearfil Porcelain Bond; C505694:Clearfil S3 Bond; C438313:Clearfil SE Bond; D003738:Dental Cements; D017220:Dentin-Bonding Agents; D004853:Epoxy Resins; D008689:Methacrylates; C076808:Monobond S; D016877:Oxidants; D019279:Resin Cements; D012821:Silanes; D011791:Quartz; D006861:Hydrogen Peroxide