Self-adhesive resin cements (RCs) activate matrix metalloproteinase
(MMP) and cathepsin-related collagen degradation, and gallic acid (GA)
inhibits the activity of both MMPs and cysteine cathepsins. The purpose
of this study was to evaluate the setting time, biaxial flexural
strength, and Vickers hardness of self-adhesive RCs after the addition
of two different concentrations of GA. RelyX U200 (3M ESPE) and Panavia
SA (Kuraray) were modified with 0.5 and 1 wt% GA. The setting time of
five samples in each RC group was assessed using a thermocouple
apparatus as described in the ISO 4049 test. Biaxial flexure strength
was measured using a universal testing machine until failure. Vickers
hardness was measured with three randomized indentations on the surface
of each resin disc. RCs without GA were used as control. Data were
analyzed using a one-way analysis of variance and Tukey’s HSD test (α =
0.05). The setting times ranged from 2.4 to 4.6 min for RelyX and from
4.9 to 6.0 min for Panavia. The biaxial flexure strength ranged from
76.5 to 109.7 MPa for RelyX and from 73.3 to 108.2 MPa for Panavia.
Vickers hardness values ranged from 41.6 to 58.6 for RelyX and 27.2 to
33.6 for Panavia. The addition of 0.5 and 1 wt% GA to improve durability
of resin-dentin bonds had no adverse effects on setting time, whereas
the biaxial flexure strength and Vickers hardness values for the tested
materials were significantly reduced.