Study of the self life of three kinds of experimental dentin self-etching primers / 实用口腔医学杂志

ABSTRACT

Objective:To observe the effect of storage period of three experimental dentin self-etching primers on the shear bond strength.Methods:Three experimental primers with 2-hydroxyethyl methacrylate (HEMA)or N-methacryloyl glycine (NMGly)as a hydrophilic monomer and 1 0-methacryloxydecyl dihydrogen phosphate(MDP)or N-methacryloyl-2-aminoethylphosphonic acid (NMEP) as an acid monomer,were designed.Immediately after preparation of the samples of MDP-HEMA,MDP-NMGly and NMEP-NMGly, the primers were stored at 40 ℃for 0,6 and 1 4 weeks.At the end of each storage period,the shear bond strength of resin to dentin(n=1 4)and the pH value of the primers were measured.Results:After storage at 40 ℃ for 1 4 weeks,the shear bond strength of MDP-HEMA decreased from (1 7.61 ±1 .56)MPa to (7.53 ±1 .76)MPa;however the bond strenth of MDP-NMGly and NMEP-NMGly did not decrease;most of the specimens of MDP-HEMA and MDP-NMGly exhibited an interfacial failure of the resin from the dentin sur-face;however NMEP-NMGly exhibited a cohesional failure of the dentin and/or resin.The SEMimages showed a separation of resin and dentin of MDP-HEMA and MDP-NMGly had storaged at 40 ℃for 1 4 weeks;while the interface of NMEP-NMGly did not change.Con-clusion:The NMEP-NMGly primer has noticeably higher hydrolytic stability than the MDP-HEMA and MDP-NMGly primers.