Effect of Adhesives and Thermocycling on the Shear Bond Strength of a Nano-Composite to Coronal and Root Dentin

Abstract

SUMMARYObjectives: To evaluate the effects of "etch & rinse" vs "self-etch" adhesives and thermocycling on the shear bond strength (SBS) of a nano-composite to coronal and root dentin. Materials and Methods: Fifty-six extracted human molars were mounted and ground to expose coronal and root dentin surfaces and were randomly divided into two groups according to adhesive system: SE-a two-step self-etch adhesive (Adper SE Plus, 3M ESPE) and ER-an etch & rinse adhesive (Adper Single Bond 2, 3M ESPE). The adhesives were applied to the coronal and root dentin of the mounted teeth. A nano-composite (Filtek Supreme XT, 3M ESPE) was applied to both dentin surfaces. The bonded specimens were stored in distilled water at 37°C for 24 hours. Half of the bonded specimens were tested for SBS in a universal testing machine without thermocycling. The remaining specimens were thermocycled (500 cycles between 5°C and 55°C) prior to SBS testing. Two specimens from each group were kept for Scanning Electron Microscope evaluations of the adhesive interfaces. Failure modes were determined under a stereomicroscope. The mean SBS value of each group was calculated, and the results were subjected to ANOVA, Duncan test and Paired samples t-test (p=0.05).Results: Thermocycling did not affect the SBS of coronal dentin for either adhesive. However, it affected the SBS of SE in root dentin (p<0.05). The Clinical RelevanceThe performance of an adhesive system may differ according to the dentin substrate and thermocyling. ©Operative Dentistry, 2010, 35-5, 522-529 523 two different dentin substrates did not exhibit a significant difference except for higher values in root dentin with the SE group without thermocycling. The greatest number of cohesive failures was observed in root dentin with SE adhesive; however, the failure modes were mainly adhesive for the other groups.Conclusion: The SE adhesive exhibited higher SBS values than the ER adhesive in root dentin. Thermocycling did not affect the SBS in coronal dentin for either adhesive but it decreased the SBS of SE in root dentin.

Flexural Strength of Preheated Resin Composites and Bonding Properties to Glass-Ceramic and Dentin

“…Comparing the two studies several differences could be observed: the adhesive system, the duration of water storage, thermocycling and the adhesive area. A more recent study found very similar results to the present study for FSXT (in a range from 11.01 ± 4.56 MPa to 15.36 ± 6.00 MPa) [33], although differing in a few parameters, like other adhesives and no thermocycling. A review [34] demonstrated the diversity of the results of SBS tests, ranging from 3–61 MPa.…”

“…The lack of standardization is one of the problems with SBS tests. Simple testing parameters, like crosshead speed [35,36], aging process [33,37] or storage conditions of the natural teeth [38,39,40], have demonstrable influence on the results. Another deficit emphasized by Scherrer [34] was the fracture pattern.…”

Randomized Clinical Trial of Four Adhesion Strategies: 18-Month Results

“…Regarding bond strength studies, SE has resulted in statistically higher dentin bond strengths than EB. 30 The bond strengths obtained with SE are not affected by thermal fatigue when bonded to coronal dentin 31 ; this may be a result of minimal residual water left entrapped within the dentin-adhesive interface.…”

Enhanced resin titanium adhesion with silane primers using tribochemical silica-coating

“…On the other hand, a sharp increase in adhesion strength after 6,000 cycles was observed in the group-BM. This could be attributed to release of stresses generated during the polymerization contraction of resin composite 20) . Moreover, the cross-linking silane (BTSE) together with the functional silane (ACPS) might improve bonding by forming a 3D siloxane film that contributed to bonding between the dissimilar materials.…”

“…Regardless of the increase in adhesion strength values in group-BM, a sharp decline in the adhesion strength values in all other experimental groups is in accordance with some previous studies 1,10,21,22) . Nevertheless, thermo-cycling is a widely used and accepted rapid, accelerated aging method used in laboratories, in addition to the shear bond strength test, regardless of their undisputable limitations 20) . The experimental silanes showed promising results with Multilink ® Speed resin composite cement in both baseline and thermo-cycled study groups.…”