In vivo evaluation of inflammation and matrix metalloproteinase expression in dental pulp induced by luting agents in dogs

Abstract

Objectives: To evaluate the inflammatory tissue response and matrix metalloproteinase (MMP)-2 and -9 expression in the pulp-dentin complex in response to RelyXTM Unicem (RU) and Ketac CemTM Easymix (KC) cements. Methods: Class V cavities were prepared in 56 teeth from six dogs, and indirect pulp capping was performed using RU (n=20), KC (n=20), zinc oxide, and eugenol cement (control, n=16). At 7 and 70 days following indirect pulp capping, the animals were euthanized, and tissues were removed for histological evaluation. The distance from the cavity floor to the odontoblastic layer was measured, and the numbers of inflammatory cells, fibroblasts, and odontoblasts were counted in pulp tissue. MMP-2 and -9 expression levels were immunohistochemically assessed. Statistical analyses were performed for all experiments (significance level=5%). Results: The dentin remnant thickness between the cavity floor and the pulp chamber was similar for all materials, ranging from 469 to 739 µm (p>0.05). At 7 days, KC and RU induced a small inflammatory response in the pulp-dentin complex, similar to the control (p>0.05). At 70 days, RU induced a tissue response characterized by fewer odontoblasts and more mononuclear cells (p 0.05). Luting agents induced low levels of MMP-2 and MMP-9 expression, similar to the control (p>0.05). Conclusion: KC and RU luting agents are compatible materials for use in deep cavities close to dental pulp tissue, although RU led to a slightly diminished odontoblastic population with a higher percentage of mononuclear cells.