eng Science and Education Publishing International Journal of Dental Sciences and Research 2333-1259 2018-01-04 5 6 150 158 10.12691/ijdsr-5-6-4 IJDSR2017564 article Labib Mohamed Labib 1 Sameh Mahmoud Nabih 2 Ahmed Mohammed El-Marakby labibrlabib@gmail.com 3 4 Departments of Restorative Dental Sciences and Preventive Dental Sciences, Alfarabi Colleges, Riyadh, Kingdom of Saudi Arabia Department of Operative Dentistry, Al Azhar University, Cairo, Egypt Department of Restorative Dental Sciences, Al-Farabi colleges, Riyadh, Saudi Arabia 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. http://pubs.sciepub.com/ijdsr/5/6/4/ijdsr-5-6-4.pdf SEM EDX microtensile nanoleakage Heliobond G-aenial bond