Development of new bonding materials with high adhesive strength to dentin using blended calcium salts of MDP

In this experiment, calcium salt (MDP-Ca) was synthesized from methacryloyloxydecyl dihydrogen phosphate (MDP), which is an adhesive monomer, and blended into a bonding system (Hybrid Coat: HC). The results from the microtensile and the indentation hardness revealed that HC with 1.50% MDP-Ca (MDCP) had higher values. In the FE-SEM observations, MDCP began to change its structure with a dense etching pattern after 24 h of immersion earlier than HC. These results indicated that MDP-Ca strengthened the mechanical structure of the hybrid layer because the initial bonding strength and indentation hardness of MDCP were greater than those of HC. Then MDCP was observed to have a dense structure that was resistant to ion etching treatment within 24 h. Thus, the addition of an appropriate concentration of MDP-Ca improved the initial bonding strength and mechanical properties of the prototype bonding material and formed a hybrid layer that was useful as a coating material.