The research aims to evaluate the micro shear bond strength of the calcium silicate cement (Biodentine) and the glass ionomer cement (GIC) to dentine. The study was performed using upper or lower premolars, and samples were divided into six equal subgroups according to the time period (3 h, 1 day, 1 week, 2 weeks, 4 weeks, 8 weeks), in order to study changes in the values of shear bond strength with time. The comparative study showed that the success rate of adhesion in the Biodentine group was smaller than that in the GIC group for the tested premolars after 3 hours and one day, whereas the success rate in the Biodentine group was greater than that in the GIC group for the tested premolars after 8 weeks. Results showed a positive correlation between the mean values of shear bond strengths and the studied time in Biodentine group, which ranged from 1.49 ± 0.18 MPa at 3 hours to a maximum value of 2.65 ± 0.26 MPa after 8 weeks. While there was a negative correlation between the mean values and the studied time in the GIC group and values ranged from 3.02 ± 0.13 MPa at 3 hours and 2.06 ± 0.09 MPa at 8 weeks. The study showed the advantage of Biodentine compared with GIC in terms of micro-bonding to dentine, which can have a clinically significant importance in preventing the micro leakage and reducing bacterial contamination.