Abstract: Objective　To analyze the effect of 10-MDP-calcium salt formation on dentin bonding performance. Methods　Using the etch-and-rinse technique mode, the teeth were randomly divided into the following 4 groups(n=5) according to the treatment method of the dentin surface and the choice of the adhesive, and the dentin/resin bonding specimens were made：① in the control group, the single bond 2(SB2) was directly treated and bonded;② in the 10-MDP group, the dentin surface was pretreated with a self-prepared primer containing phosphate monomer 10-MDP before using SB2 treatment for bonding;③ in the CHX group, the dentin surface was pretreated with chlorhexidine(CHX) before bonding with SB2;④ in the SBU group, single bond universal(SBU), a MDP-containing universal adhesive, was directly used for bonding. The bonding strength was measured by micro-tensile bond strength(μTBS), and the dentin surface treated with self-prepared 10-MDP primer and two kinds of dentine adhesives was characterized by X-ray diffraction(XRD) and in situ zymography test to analyze the effect of 10-MDP-calcium salt formation on the dentin bonding performance. Results　The results of micro-tensile bond strength test showed that there was no significant statistical difference between the adhesive specimens treated with different methods after 24 h water-storage(P>0.1). After 6 months water-storage, compared with the 10-MDP group and the SBU group, the micro-tensile strength test of the control group was significantly reduced(P<0.05), while the micro-tensile strength test of the CHX group did not change significantly(P>0.05). The XRD results showed that the characteristic peaks of 10-MDP-calcium salt formation were detected in both the 10-MDP group and the SBU group, indicating the formation of 10-MDP-calcium salt. The results of in situ zymography showed that there was no significant difference between the 10-MDP group and the SBU group. The fluorescence intensity of the hybrid layers in the control group was significantly higher than that of the 10-MDP group and the SBU group, while the fluorescence intensity of the CHX group was lower than that of the 10-MDP group and the SBU group. Conclusion　The formation of 10-MDP-calcium salt can protect the exposed collagen fibers from contacting MMPs and avoid hydrolysis, thereby enhancing the dentin/resin bonding performance.

Key words: Dentin bonding, MMPs, MDP, MMPs inhibitor