Introduction: Glass-ionomer cements (GICs) may be the restoration of choice in patients with a high caries risk, owing to their anticariogenic and remineralizing capabilities. Regrettably, as compared to other restorative materials, it has lower flexural and tensile strength, fracture resistance, and a higher rate of wear, all of which have an implication on its survival rates when used in load bearing areas. Materials and methods: Dentin Conditioner (10% Polyacrylic acid), EQUIA®Forte Fil (Glass ionomer with glass hybrid technology), EQUIA®Forte Coat (Low-viscosity nano-filled resin) and Zirconomer®Improved (Zirconia-reinforced glass ionomer) were used. Sixty patients with high caries risk were selected. Class II occlusal slot cavities were prepared in the first permanent molar and restored randomly by two restorations, either; EQUIA®Forte Fil or Zirconomer ® Improved. Restorations were evaluated at baseline, after six months and one year. Results: There was no statistically significant difference between both materials for the tested properties at base line. At six months follow up time, 92% of the EQUIA®Forte Fil group and 68% of the Zirconomer ® Improved group were clinically successful. Meanwhile, at 12 months follow up time, 88% of the EQUIA®Forte Fil group and 40% of the Zirconomer ® Improved group were clinically successful with significant difference between them at both six and 12 months. Conclusions: Glass ionomer with glass hybrid technology exhibited better clinical performance than zirconia-reinforced glass ionomer in class II slot cavities after six months and one year with high success rate in the purpose of restoring posterior permanent teeth.