RESIN MONOMERS TEGDMA, HEMA AND SELFT-ETCHING ADHESIVES DON'T REGULATE IL6 GENE EXPRESSION IN HPCS

OBJECTIVES The evolution of dental materials used in clinical practice, is a research area of considerable involvement. The resin monomers are the most commonly utilized materials in restorative dentistry; one of the outstanding problems, in the employment of dental polymer resins, is represented by micro-leakage that occur at the interface between the sealer and the tooth surface, causing bacterial invasion and secondary caries [1]. The diffusion of monomers through dentin residual influence the viability of odontoblasts and the physiological activity of dental pulp. TEGDMA and HEMA can reach the pulp tissue and penetrate into the cytosol, induce cytotoxicity, genetic damage, oxidative stress in several cell phenotypes [2] and stimulate interleukin -6 (IL-6) production [4]. Currently it is not clear whether TEGDMA, HEMA regulate the IL6 gene transcription but the target of our research is to evaluate the activation or inhibition of IL6 caused by different resin dental materials (monomers and dentin adhesive systems XT primer and bond) in primary human pulp cells. METHODS Human pulp fibroblasts (HPCs), were isolated from the pulp of the eighths extracts from different patients. HPCs were stimulated with the monomers TEGDMA, HEMA and three dental adhesives (primer, bound and xt) at different concentrations and after incubation for 24h we carried out the MTT cytotoxicity test and then the quantitative analysis (QRT-PCR) of IL6 gene expression. RESULTS The MTT assay did not shows cytotoxicity with tested materials (HEMA, TEGDMA and primer, bond, xt) at the concentrations indicated in the user manual of the three products. The QRT-PCR assay did not reveal a change in the activity of IL-6 in HPCs stimulated vs. control. CONCLUSIONS IL 6 is an inflammatory cytokine involved in several disorders of the oral cavity; a polymorphism of this cytokine is associated with chronic periodontitis [5]. It was shown that HEMA monomer, is able to reduce the growth of dental pulp mesenchymal stem cells (DP-MSC) and stimulates the IL6 production [6]. Our results show that TEGDMA, HEMA and dental adhesives, does not alter the IL6 gene expression in HPCs stimulated with the materials at the indicated concentrations. Our group is presently committed to confirm the results and also to extend the research to the IL-6 receptor. Our target is demonstrated that resin monomers and dentin adhesives tested, do not trigger an inflammatory process in the dental pulp.