In Vitro Evaluation of Dental Resin Monomers, Triethylene Glycol Dimethacrylate (TEGDMA), and 2-Hydroxyethyl Methacrylate (HEMA) in Primary Human Melanocytes: A Pilot Study

Abstract

Triethylene glycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA), two resin monomers often used in dental restorative materials, are leached due to insufficient polymerization and contact cells of the oral cavity. Despite reports on the cytotoxicity of these monomers on different oral cells, their effects on oral melanocytes remain unknown. This first report provides novel data on the impact of TEGDMA and HEMA monomers on melanocyte viability and functions by utilizing primary human melanocytes from lightly pigmented (HEMn-LP) foreskin as a representative model of oral melanocytes. Results show that TEGDMA induced higher cytotoxicity than HEMA and significant morphological alterations (increased dendricity) in melanocytes at the lowest concentration of 0.25 mM onwards. HEMA achieved similar effects but only at an 8-fold higher concentration (2 mM), while lower concentrations did not induce any change in cellular melanin or morphology. HEMA suppressed intracellular tyrosinase activity at 1 and 2 mM, while TEGDMA had no effect, although none of the monomers altered tyrosinase activity directly in an acellular system. TEGDMA and HEMA did not alter cellular ROS production. TEGDMA suppressed LPS-induced IL-6 cytokine secretion in cells to a greater degree than HEMA, indicating its greater capacity to dampen the immune response. Our findings demonstrate that TEGDMA and HEMA at different concentrations induce cytotoxicity to melanocytes, stimulate their dendricity and impair immune responses, indicative of altered melanocyte homeostasis. Furthermore, it is worth considering alternative monomers in light of the cytotoxicity exhibited by TEGDMA at lower millimolar concentrations compared to HEMA as well as its significant impact on melanocyte differentiation and immune function.

Dental Resin-Based Luting Materials—Review

“…Extant evidence suggests that such undesirable effects may lead to hypersensitivity reactions in some patients [15] and even facilitate the development of cariogenic bacteria [91]. Extant research, however, shows that due to its easy solubility in patients' saliva, TEGDMA has a greater cytotoxic potential compared to other dimethacrylate monomers [92][93][94]. We concur with the statements made by other authors who have evaluated these monomers in other cells, such as pulp cells and fibroblasts or macrophages.…”

Comparative Study of the Effects of Curcuminoids and Tetrahydrocurcuminoids on Melanogenesis: Role of the Methoxy Groups

“…The evaluation of the direct effects of the six compounds on tyrosinase enzyme activity was conducted with mushroom tyrosinase enzyme in conjunction with L-DOPA substrate. This evaluation was performed utilizing the methodology outlined in our previous publications [38,49].…”

Cyclocurcumin, a Minor Curcuminoid, Is a Novel Candidate for Hypopigmentary Skin Disorders with Melanogenesis-Stimulating Capacity

“…The direct effects of CYC (5,10,20,40,50, and 80 µM) on tyrosinase activity using a mushroom tyrosinase enzyme source and L-DOPA substrate solution were determined based on the method in our previously published studies [45,79]. KA at 0.5 mM was used as a control that is known to inhibit mushroom tyrosinase activity [185]. Briefly, 80 µL of samples was combined with 100 µL of 6 mM L-DOPA solution in a microplate, and the rate of dopachrome formation was measured kinetically for 10 min at 475 nm.…”