Human and rat mononuclear cell proliferation show different sensitivity, in vitro, to single constituents of dental composite resins

Biocompatibility of Resin-based Dental Materials

Oral and mucosal adverse reactions to resin-based dental materials have been reported. Numerous studies have examined the biocompatibility of restorative dental materials and their components, and a wide range of test systems for the evaluation of the biological effects of these materials have been developed. This article reviews the biological aspects of resin-based dental materials and discusses the conventional as well as the new techniques used for biocompatibility assessment of dental materials.

Histo-blood group antigen expression and proliferative activity of fibroblasts treated with dental monomers

The present work is focused on examining the effect of the structurally similar dental monomers bis-GA and bis-GMA on the expression of histo-blood group antigens (HBGAs) in comparison with fibroblast vitality and proliferation. The fibroblast cell line McCoy-Plovdiv was cultivated in a serum-free medium and was treated with both monomers. Cell vitality was measured by the crystal violet test. Mitotic index and cell morphology were assessed. An immunocytochemical technique was applied to follow the expression of proliferative antigens PCNA and Ki-67 and of HBGA. The expression level of HBGA was measured by an improved pixel selection algorithm with proprietary software. The lowest concentration of 2.5 micromol/L did not significantly affect morphology, vitality, or proliferation activity. Interestingly, the quantitative analysis revealed augmented expression of HBGA B at 2.5 micromol/L. The higher concentrations of the dental monomers reduced cell vitality and mitotic indices and altered proliferative antigen expression. Bis-GA proved to be more toxic than bis-GMA and caused more prominent alterations including greater enhancement of HBGA B expression. We present novel evidence for altered expression of proliferative antigens and enhanced expression of HBGA B in fibroblasts treated with dental monomers bis-GA and bis-GMA suggesting that these substances affect cell morphology, proliferative activity, and antigenic profile.

HEMA bound to self-protein promotes auto-antibody production in mice

While several studies report that acrylic monomers contained in dental materials may cause hypersensitivity reactions, little is known of the associated immune response. Here we address the potential of 2-hydroxyethyl-methacrylate (HEMA) to bind to endogenous protein and elicit auto-antibody production in vivo. Albumin was incubated with HEMA at various times and pH. Following confirmation of the conjugation by inhibition of trinitrophenyl (TNP) binding, female Balb/c mice received HEMA conjugated to mouse serum albumin (MSA) in Freund's incomplete adjuvant or saline subcutaneously. ELISA was used to determine the serum antibody responses to native and modified MSA. IL-2 production in spleen cell cultures stimulated with HEMA-conjugated MSA was measured. HEMA reacted with serum albumin at physiological conditions. HEMA-conjugated MSA induced IL-2 secretion and production of IgG antibodies to native MSA. The results suggest that modification of an endogenous protein like serum albumin with HEMA may defeat the control of immune responses to this self-protein.