The objective of this study was to determine if Gluma dentin desensitizer (5.0% glutaraldehyde and 35% HEMA in water) can inhibit the endogenous MMPs of dentin matrices in 60s and to evaluate its effect on dentin matrix stiffness and dry mass weight.Dentin beams of 2mm×1mm×6mm were obtained from extracted human third molars coronal dentin. To measure the influence of Gluma treatment time on total MMP activity of dentin, beams were dipped in 37% phosphoric acid (PA) for 15s and rinsed in water. The acid-etched beams were then dipped in Gluma for 5, 15, 30 or 60s, rinsed in water and incubated into SensoLyte generic MMP substrate (AnaSpec, Inc.) for 60min. Controls were dipped in water for 60s. Additional beams of 1mm×1mm×6mm were completely demineralized in 37% PA for 18h, rinsed and used to evaluate changes on the dry weight and modulus of elasticity (E) after 60s of Gluma treatment followed by incubation in simulated body fluid buffer for 0, 1 or 4 weeks. E was measured by 3-pt flexure.Gluma treatment inhibited total MMP activity of acid-etched dentin by 44, 50, 84, 86% after 5, 15, 30 or 60s of exposure, respectively. All completely demineralized dentin beams lost stiffness after 1 and 4 weeks, with no significant differences between the control and Gluma-treated dentin. Gluma treatment for 60s yielded significantly less dry mass loss than the control after 4 weeks.The use of Gluma may contribute to the preservation of adhesive interfaces by its cross-linking and inhibitory properties of endogenous dentin MMPs.