Effect of MMP Inhibitors on Shear Bond Strength of Adhesive to Dentin after Different Drying Techniques: An In-Vitro...

Instead of excessive drying or wetness, maintaining an optimal moisture level on the dentin surface may enhance the polymerization process of certain monomers. The study was intended to contrast and evaluate the effect of Matrix metalloproteinases (MMPs) inhibitors (Chlorhexidine (CHX) and Doxycycline (DOX)) on the shear bond strength (SBS) of adhesive dentin interface after different drying techniques (blotting with tissue paper (TP) and damp cotton pellet (CP)).

Ninety molars collected were split into three groups according to the materials used during the acid etching step: Group A (control): 37% phosphoric acid only; Group B: 37% phosphoric acid followed by 2% CHX; Group C: 37% phosphoric acid followed by 2% DOX. Each group was categorized into 2 subgroups based on the drying methods used after etching (TP and damp CP). A universal bonding agent was applied after this and composite restoration was placed onto the dentin and cured. The samples underwent thermocycling for 500 thermocycles for degradation of the adhesive surface. The SBS of the specimens was appraised with a universal testing machine until fracture.

The CHX group blotted with TP (20.98 ± 0.29 MPa) had the highest SBS among the study sample. This was eventually followed by the CHX group blotted with the CP (18.99 ± 0.28 MPa), DOX blotted with TP (19.73 ± 0.51 MPa), and DOX blotted with the CP (17.09 ± 0.55 MPa). The least SBS was observed in the control group blotted with TP (16.9 ± 0.22 MPa) and then by CP (13.78 ± 0.55 MPa).

The study showed that CHX had a superior effect on the SBS when compared to DOX. Among the drying agents used TP yielded better results than drying with a damp CP. The overall SBS was high in the CHX group dried with TP and the least strength was shown by the control group where treatment with an MMP inhibitor was done.