Labib Mohamed Labib¹, Sameh Mahmoud Nabih², Ahmed Mohammed El-Marakby^{3, 4,}

Purpose: The purpose of the present study is to evaluate nanoleakage and microtensile bond strength of different resin composite materials bonded to dentin. Material and methods: Teeth will be divided into three main equal groups according to filling material. Each main equal group will be subdivided into two equal subgroups according to application mode (self-etch vs. Etch and rinse mode) (n=20). Then each subgroup will be further divided in to smaller Subgroups. Subgroup 1: using filtek TM Z250 with G-bond plus (G-aenial) (self-etching mode), then application of hydrophopic resin coating (Heliobond). Subgroup 2: using filtek TM Z250 with G-bond plus (G-aenial) (self-etching mode), without application of hydrophobic resin coating (Helio bond). Subgroup 3: using filtek TM Z250 with G-bond plus (G-aenial) (etch and rinse mode), then application of hydrophobic resin coating (Heliobond). Subgroup 4: using filtek TM Z250 with G-bond plus (G-aenial) (etch and rinse mode), without application of hydrophobic resin coating (Heliobond). Conclusion: An extra hydrophobic layer coating improved the immediate in vitro performance (µTBS and NL) of the universal adhesive systems that studied in SE mode. However, NL pattern is material-dependent and aging stability seems not to be related with the adhesive strategy.

SEM, EDX, microtensile, nanoleakage, Heliobond, G-aenial bond