J Adhes Dent 19 (2017), No. 6 12. Jan. 2018
J Adhes Dent 18 (2016), No. 2 (15.04.2016)
Page 125-134, doi:10.3290/j.jad.a35907, PubMed:27042705
Effect of Silane Reaction Time on the Repair of a Nanofilled Composite Using Tribochemical Treatment
Pilo, Raphael / Brosh, Tamar / Geron, Valery / Levartovsky, Shifra / Eliades, George
Purpose: To investigate the influence of silane reaction time on the repair strength of an aged nanofilled composite and to characterize the bonding mechanism.
Materials and Methods: Nanofilled composite disks (n = 110, Filtek Supreme XT) were aged for 90 days in water. After tribochemical treatment (CoJet-Sand), the specimens were assigned to 5 groups (n = 22), primed with silane (Espe-Sil), and left to react for 1, 2, 3, 4, and 5 min. A thin layer of adhesive (Visio-Bond) was applied and a new composite with the same dimension was placed and cured. Non-aged specimens immediately layered and cured using the incremental technique served as controls. After aging (30 days in water plus 5000 thermal cycles), the interface was subjected to a shearing force until failure. Failure mode was evaluated under a stereomicroscope and scanning electron microscopy (SEM). Additional aged and treated surfaces were evaluated for morphology as well as elemental and molecular composition using SEM/EDX and ATR-FTIR.
Results: The mean shear bond strength (SBS) of the repaired specimens was 53.9 ± 8.6 MPa, with no significant difference among the various reaction times, but significantly lower compared to the control (88.1 ± 12.5 MPa). Tribochemical treatment created an irregular surface morphology with particles imbedded in the aged surface. Interfacial SEM/EDX analysis showed a 5-μm non-uniform high atomic number zone rich in Al and Si.
Conclusion: Tribochemical treatments for repairing composite using a short silane reaction period (1 min) are equally effective as the prolonged reaction periods (2 to 5 min), yielding interfacial shear strength of ~60% of unrepaired material.
Keywords: resin composite, repair, tribochemical, silane, reaction time, surface, interfacial characterization