Abstract:

Objective To analyze chemical mechanism of bonding improvement of zirconia via 10-methacryloyloxydecyl dihydrogen phosphate (MDP) conditioning. Methods Various models were created for tetragonal zirconia crystals, molecular MDP, and MDP complex, and tetragonal zirconia crystal. Thermodynamic methods were used to analyze configuration between MDP and tetragonal zirconia crystal through calculation of their Gibbs free energy values and equilibrium constants. Results Two potential configurations (double- and single-coordinate) may occur between MDP and ZrO₂ crystal clusters. Thermodynamic calculations showed that -147.761 and -158.073 kJ·mol^-1 Gibbs free energy were required to form single- and double-coordinate configurations; their negative signs indicate that reactions for both configurations can occur. Equilibrium constant for single-coordinate configuration was 7.72×10²⁵, which was less than that of double-coordinate configuration (4.95×10²⁷), suggesting that the latter was more stable. Conclusion MDP can spontaneously establish a double-coordinate configuration with zirconia.

Key words: quantum chemistry, reaction mechanism, zirconia, bonding, phosphate monomer, primer