IADR Abstract Archives
Nanomolar Inhibitor of MMP Activity for Hybrid Layer Preservation
Objectives: N-Isobutyl-N-(4-methoxyphenylsulfonyl)-glycyl hydroxamic acid (NNGH) has been shown to strongly inhibit MMP3 and modulate cancer progression and metastasis. The aim of this study is to evaluate its potential effect in preserving the hybrid layer, increasing the longevity of dental restorations.
Methods: MMP-2 and -9 activity was measured through a fluorometric assay using DQ™-gelatin as substrate. Rat tendon collagen (RTT) degradation was measured in disks (n=3) crosslinked with NaOH/DMEM. Disks were incubated with collagenase solution with no inhibitor, 50μM or 100μM NNGH, at 37°C for 6, 24 or 72h. Lyophilized discs were weighed and imaged with SEM. Microtensile bond strength (MTBS) was assessed in human third molars restored with BisGMA/HEMA experimental adhesives with 0 or 50/100μM NNGH in a 40% EtOH solvent system, with or without dentin pre-treatment with 50μM NNGH solutions. 1x1 mm2 sticks were incubated in water or biofilm for 1 week (n=3). Data were analyzed with one-way ANOVA or Kruskal-Wallis/Tukey’s test (α=0.05).
Results: Enzymatic activity of both MMPs -2 and -9 was significantly reduced with all NNGH concentrations (p<0.001). The collagen degradation statistically increased with incubation time (p<0.001) except for 100μM NNGH, where no degradation was observed in relation to the control (p<0.001). The MTBS was not affected by the addition of NNGH (water: p=0.052; biofilm: p=0.175). However, the control groups showed statistically significant reduction in MTBS between water and biofilm storage, whereas the NNGH groups were able to sustain MTBS values after being challenged in biofilm.
Conclusions: NNGH was able to inhibit MMP activity at the nanomolar scale, which led to reduced collagen degradation at 100μM. The groups pretreated with NNGH solutions or restored with NNGH-containing adhesives were able to sustain MTBS values after tested in biofilm.
Methods: MMP-2 and -9 activity was measured through a fluorometric assay using DQ™-gelatin as substrate. Rat tendon collagen (RTT) degradation was measured in disks (n=3) crosslinked with NaOH/DMEM. Disks were incubated with collagenase solution with no inhibitor, 50μM or 100μM NNGH, at 37°C for 6, 24 or 72h. Lyophilized discs were weighed and imaged with SEM. Microtensile bond strength (MTBS) was assessed in human third molars restored with BisGMA/HEMA experimental adhesives with 0 or 50/100μM NNGH in a 40% EtOH solvent system, with or without dentin pre-treatment with 50μM NNGH solutions. 1x1 mm2 sticks were incubated in water or biofilm for 1 week (n=3). Data were analyzed with one-way ANOVA or Kruskal-Wallis/Tukey’s test (α=0.05).
Results: Enzymatic activity of both MMPs -2 and -9 was significantly reduced with all NNGH concentrations (p<0.001). The collagen degradation statistically increased with incubation time (p<0.001) except for 100μM NNGH, where no degradation was observed in relation to the control (p<0.001). The MTBS was not affected by the addition of NNGH (water: p=0.052; biofilm: p=0.175). However, the control groups showed statistically significant reduction in MTBS between water and biofilm storage, whereas the NNGH groups were able to sustain MTBS values after being challenged in biofilm.
Conclusions: NNGH was able to inhibit MMP activity at the nanomolar scale, which led to reduced collagen degradation at 100μM. The groups pretreated with NNGH solutions or restored with NNGH-containing adhesives were able to sustain MTBS values after tested in biofilm.
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