Bonding performance of a newly developed step-less all-in-one system on dentin

Abstract

The purpose of this study was to evaluate the short-term µTBS (Micro-tensile bond strength) and microscopic (SEM and TEM) observation of four recent adhesives. One adhesive was an experimental step-less 1-step system (LLB-2, Tokuyama Dental), which is an all-in-one system without the light-curing step in the application process. The other two were self-adhering light-cured flowable composite resin systems FLD (Fusio Liquid Dentin, Pentron Clinical Technologies) and VF (Vertise Flow Dental Restorative Materials, Kerr Corporation), which combine all the bonding steps together. A 2-step self-etching system MG (Clearfil MegaBond, Kuarary Medical) was employed as the control group in this study. The µTBS of MG was the highest (79.0 MPa) followed by that of LLB-2 (63.1 MPa), FLD (23.6 MPa), and VF (13.1 MPa). The microscopic observations showed that MG and LLB-2 had an approximately 20 µm and 5 µm adhesive layer respectively, without bubble or gap-formation at the resin-dentin interface, which were found in FLD and VF.

Microtensile bond strength of a newly developed resin cement to dentin

“…This is also backed by both TEM and SEM observations, which agree with the high µTBS of ECD under both light and dark conditions 19,20) . TEM observation showed a very thin hybrid layer, which may be caused by the structural characteristics of 3D SR monomer and the intermediate acidity of the primer as was reported previously 19,20) ( Figs. 2b and d).…”

“…This unique curing system was so called "Touch and Cure". These unique characteristic of "Touch and Cure" system could contribute to the high µTBS regardless of the curing condition 19) . ECD primer contains nano-fillers.…”

“…The primer and the resin cement for ECD were required to be used together. The primer contains several co-initiators, and the resin cement paste contains an initiator, thus, the self-curing interaction between the primer and the resin cement may initiate conversion when they were contacted even without light curing 19) . Free radicals released by BPO, contained in resin composite cement paste could improve polymerization of the primer layer.…”

“…This result suggested that the 3D SR monomer could contribute to better bond durability 16) . Fu et al also reported about this functional monomer, which was a component of a new self-bonding system for direct restoration 19) . In their study, 3D SR monomer could produce good bonding with dentin structure.…”

Bond performance of “Touch and Cure” adhesives on resin core systems

“…As for the comparison between light-and darkcondition, DC and UN resulted in lower µTBS under dark condition 24) . This effect might be explained by a lower degree of conversion of the two adhesives under dark condition 23) .…”