[PERSON]  
1 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (M.B.-P.j. ); [EMAIL_ADDRESS] (S.J.K. ); [EMAIL_ADDRESS] (I.M.) Uzay Koc Vural  
2 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (M.B.-P.j. ); [EMAIL_ADDRESS] (S.J.K. ); [EMAIL_ADDRESS] (I.M.) [PERSON]  
1 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (M.B.-P.j. ); [EMAIL_ADDRESS] (S.J.K. ); [EMAIL_ADDRESS] (I.M.) Uzay Koc Vural  
2 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (U.K.V.) Uzay Koc Vural  
2 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (M.B.-P.j. ); [EMAIL_ADDRESS] (S.J.K. ); [EMAIL_ADDRESS] (I.M.) Uzay Koc Vural  
2 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (U.K.V.) Uzay Koc Vural  
2 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (M.B.-P.j. ); [EMAIL_ADDRESS] (S.J.K. ); [EMAIL_ADDRESS] (I.M.) Uzay Koc Vural  
2 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (M.B.-P.j. ); [EMAIL_ADDRESS] (S.J.K. ); [EMAIL_ADDRESS] (I.M.) Uzay Koc Vural  
2 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (M.B.-P.j. ); [EMAIL_ADDRESS] (S.J.K. ); [EMAIL_ADDRESS] (I.M.) Uzay Koc Vural  
2 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (U.K.V.) Uzay Koc Vural  
2 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (M.B.-P.j. ); [EMAIL_ADDRESS] (S.J.K. ); [EMAIL_ADDRESS] (I.M.) Uzay Koc Vural  
2 School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia; [EMAIL_ADDRESS] (M.B.-P.j. ); [EMAIL_ADDRESS] (S.  
The hardness of restorative material is critical for the clinical longevity of restorations [10]. Previous research has shown that microhardness determined by the Vickers method is a valid measure of the surface properties of GICs [11; 12]. An increased roughness can be a predisposing factor for bacterial colonization [13]; when exceeds 0.2 m, the caries risk is increased because of bacterial accumulation, plaque maturation, and acidity [14]. Therefore, surface roughness (SR) of GIC materials is often defined as a measure of the wear of materials, which strongly influences the success of restoration [15]. The main effects of GIC's anticariogenic and remineralization effects are largely due to fluoride release (FR), which is considered to be an important property of restorative dental materials and its release level has been shown to be influenced by material composition, storage conditions, and curing method [16; 17; 18]. Furthermore, it is suggested that addition of nano-sized particles enhances the release of fluoride from the GIC [19]. Having in mind the idea of developing the material with suitable biological and mechanical properties, the aim of this study was to evaluate the effect of incorporation of 2, 5, and 10 wt % HA, derived from the cuttle-fish bone by the hydrothermal method [20] in conventionally cured and light cured GIC, on microhardness and SR of GICs and to investigate its effects on chemical feature and fluoride release. The null hypothesis is that there will be no changes in microhardness, SR and FR properties of GIC after the addition of HA.