El Wakeel A.M.Elkassas D.W.Yousry M.M.Department of Conservative DentistryFaculty of Dental MedicineModern Sciences and Arts UniversityCairoEgypt; Department of Operative DentistryFaculty of Oral and Dental MedicineMisr International UniversityCairoEgypt; Department of Operative DentistryFaculty of Oral and Dental MedicineCairo UniversityCairoEgypt2020-01-092020-01-09201513057456https://doi.org/10.4103/1305-7456.156799PubMed ID :https://t.ly/2ddpGScopusObjective: This study was conducted to evaluate the microshear bond strength (?SBS) and ultramorphological characterization of glass ionomer (GI) cements; conventional GI cement (Fuji IX, CGI), resin modified GI (Fuji II LC, RMGI) and nano-ionomer (Ketac N100, NI) to enamel, dentin and cementum substrates. Materials and Methods: Forty-five lower molars were sectioned above the cemento-enamel junction. The occlusal surfaces were ground flat to obtain enamel and dentin substrates, meanwhile the cervical one-third of the root portion were utilized to evaluate the bonding efficacy to cementum substrate. Each substrate received microcylinders from the three tested materials; which were applied according to manufacturer instructions. ?SBS was assessed using a universal testing machine. The data were analyzed using two-way analysis of variance (ANOVA) and Tukey's post-hoc test. Modes of failure were examined using stereomicroscope at 25 magnification. Interfacial analysis of the bonded specimens was carried out using environmental field emission scanning electron microscope. Results: Two-way ANOVA revealed that materials, substrates and their interaction had a statistically significant effect on the mean ?SBS values at P values; ?0.0001, 0.0108 and 0.0037 respectively. RMGI showed statistically significant the highest ?SBS values to all examined tooth substrates. CGI and RMGI show substrate independent bonding efficiency, meanwhile; NI showed higher ?SBS values to dentin and cementum compared to enamel. Conclusion: Despite technological development of GI materials, mainly the nano-particles use, better results have not been achieved for both investigations, when compared to RMGI, independent of tooth substrate. � 2015 Dental Investigations Society.EnglishOctober University for Modern Sciences and Artsجامعة أكتوبر للعلوم الحديثة والآدابUniversity of Modern Sciences and ArtsMSA UniversityCementumConventional glass ionomerDentinEnamelMicroshear bond strengthNano-ionomerResin-modified glass ionomerArticlehttps://doi.org/10.4103/1305-7456.156799PubMed ID :