Inhibition of MMP activity and preservation of dentin collagen structure of zinc-releasing glass ionomer cement.

Objective: This study evaluated the ability of a novel zinc-releasing glass ionomer cement (GIC), Caredyne Restore (CR), to inhibit matrix metalloproteinase (MMP) activity and preserve dentin collagen integrity, compared with a conventional GIC (Fuji IX, FIX) and chlorhexidine (CHX), a widely used MMP inhibitor.

Methods: Demineralized bovine dentin beams were allocated to four groups: deionized water (negative control), CHX (positive control), FIX eluate, and CR eluate. MMP Activity was assessed before and after treatment using a colorimetric assay. Dentin matrix degradation was evaluated by measuring dry mass loss over 21 days in simulated body fluid and collagen fragment release after one week using Sirius Red staining.

Results: CR exhibited the greatest reduction in MMP activity (65.5 %), significantly higher than FIX (44.8 %, p = 0.02) and comparable to CHX (61 %). CR also demonstrated the lowest cumulative dry mass loss (4 %), significantly less than the control (45.8 %, p = 0.001) and FIX (p = 0.03), and comparable to CHX (13 %). Collagen fragment release was significantly reduced in the CR group (32.5 %) relative to the control (p < 0.001), comparable to CHX (27.7 %).

Conclusion: CR demonstrated significant inhibition of MMP activity and effective preservation of dentin matrix integrity compared to a conventional GIC.

Clinical Significance: The use of CR may help protect dentin collagen from enzymatic degradation, potentially improving the durability and longevity of restorations in caries-affected dentin, especially in cases with a high risk of secondary caries.