Fig. 2
The treatment of tooth specimens in Group A and Group B. a: The crown surfaces of experimental tooth specimens were coated with 2 layers of acidproof varnishes, except a reserved area on buccal surface 1 mm away from CEJ; b: After turned upside down with the occlusal surface pointed downwards and 25 μL of 2 mol/L acetate buffer added into the pulp chamber, the tooth specimens were immersed in DW or 30% H2O2 solution for 30 min at 37 °C with the level of the liquid lower than the cut surfaces of the teeth