2-Hydroxyethyl methacrylate (HEMA) promotes IgG but not IgM antibody production in vivo in mice

The Effect of Flowable Composite Resins on Periodontal Health, Cytokine Levels, and Immunoglobulins

Objective

This study investigated the effects of flowable resin composites (FCR) on the restoration of noncarious cervical lesions (NCCL) and their impact on periodontal tissues.

Materials and Methods

30 periodontally healthy patients were assigned into three groups randomly; group VF: self-adhering FCR, group NF: fluoride-releasing FCR, and group SF: microhybrid FCR. Gingival crevicular fluid (GCF) volume levels of osteoprotegerin (OPG), immunoglobulins (IgA, IgM), and interleukins (IL-1, IL-1β, and IL-10) in GCF were analyzed with ELISA tests. Clinical success rates were evaluated using USPHS criteria during the 12-month follow-up.

Results

The GCF volume was increased mostly in group SF (1.34 ± 0.09 μl). While the titer of interleukin was increased in all groups, higher increases were observed in IL-1 and IL-1β in group NF (170.78 pg/ml and 39.35 pg/ml). Increased IL-10 was observed in group VF (14.33 ± 0.85 pg/ml). IgA levels varied partially among all groups (p > 0.05), and even IgM levels were elevated immediately after the restoration process but returned to normal on the 28th day (p < 0.05). Group NF failed in most of the USPHS criteria, while the material group VF and group SF presented acceptable results except in the marginal adaptation criterion (p < 0.05).

Conclusions

Clinical efficacy of self-adhering FCR was found the best for restoration of NCCL while fluoride-releasing FCR stimulated the periodontal response and had negative effects on GCF volume, cytokine, and immunoglobulin levels.

The effects of the dental methacrylates TEGDMA, Bis-GMA, and UDMA on neutrophils in vitro

Objectives

The prevalent usage of methacrylates in modern dentistry demands good knowledge of their biological impacts. While there have been several studies demonstrating the effects of different methacrylic monomers on mononuclear white blood cells, very little is known about the effects caused by these monomers on neutrophilic granulocytes. The objective of this study was to add novel knowledge about how neutrophils are affected by exposure to triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), and bisphenol A glycol dimethacrylate (Bis‐GMA) alone or in combinations.

Materials and Methods

Isolated neutrophils were cultured in the presence or absence of methacrylates. The IL‐8 release was measured using a DuoSet ELISA development kit. Apoptosis and necrosis were analyzed using flow cytometry. The formation of neutrophil extracellular traps (NETs) was investigated using Sytox green DNA staining combined with microscopically examination of released DNA and myeloperoxidase (MPO).

Results

The release of IL‐8 was significantly increased after exposure to TEGDMA, Bis‐GMA, UDMA, or TEGDMA in combination with Bis‐GMA or UDMA compared to the unstimulated controls. Exposure to TEGDMA, UDMA, and Bis‐GMA for 24 hr separately or in combination did not affect apoptosis or necrosis of the exposed neutrophils. NET structures were formed by neutrophils after exposure to the different combinations of the methacrylates.

Conclusion

The combination of TEGDMA and Bis‐GMA had a synergistic proinflammatory effect on neutrophils by increasing the release of IL‐8 and the formation of NET structures. The changes in the normal functions of neutrophils caused by methacrylate exposure may lead to altered inflammatory response and relate to previously reported adverse immune reactions caused by these substances.

Sublingual administration of 2-hydroxyethyl methacrylate enhances antibody responses to co-administered ovalbumin and Streptococcus mutans

OBJECTIVE

The oral mucosa of patients undergoing dental procedures is often exposed to residual monomers leaking from incompletely cured acrylic resins. We investigated whether 2-hydroxyethyl methacrylate (HEMA) monomers applied to the sublingual mucosa in mice modulate the antibody responses towards co-administered ovalbumin (OVA) or live oral bacteria.

MATERIAL AND METHODS

OVA, live mouse oral commensal Lactobacillus murinus or live human oral commensal Streptococcus mutans were administered sublingually with or without HEMA to BALB/c mice on four weekly occasions. One week after the last administration, the experiment was terminated and serum antibody levels were analyzed using ELISA.

RESULTS

Significantly increased IgG and IgE anti-OVA antibody activity was found in the sera from mice immunized with OVA together with HEMA, as compared to mice immunized with OVA alone. Likewise, S. mutans together with HEMA induced an IgG anti-S. mutans antibody response that was significantly higher than the antibody response detected after application of S. mutans alone. No IgG anti-L. murinus antibody response was detected in mice immunized with L. murinus together with HEMA, as compared to the background activity.

CONCLUSIONS

We report that HEMA monomers have adjuvant properties when sublingually administered in combination with OVA or S. mutans.

Effects of the methacrylate/acrylate monomers HEMA, TEGDMA, DEGDA, and EMA on the immune system

Incomplete curing of dental fillings may lead to leakage of methacrylate/acrylate monomers, which may come in contact with different cells of the immune system in oral tissues. Very little is known about the different immunologic effects caused by these methacrylates/acrylates. The objective of the present study was to study if and how the methacrylate/acrylate monomers ethyl methacrylate (EMA) and diethylene glycol diacrylate (DEGDA) affect the immune system in vivo and in vitro in comparison to 2-hydroxyethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA). Human peripheral blood mononuclear cells were exposed to the different monomers (500 and 1000 μM) for 24 hr in vitro. BioPlex Pro™ assays were used for cytokine analysis. In vivo, BALB/c mice were immunized subcutaneously at the base of the tail with HEMA, TEGDMA, EMA, or DEGDA in combination with ovalbumin (OVA) in order to study adjuvant properties of the 4 monomers. Peripheral blood mononuclear cells exposed to DEGDA had viability less than 50% of the cells. A pattern was observed where the levels of most cytokines were elevated after exposure to HEMA or TEGDMA. Since that, many cells died after DEGDA-exposure, the only observed cytokine secretion was a significantly increased production of interleukin-18. In the in vivo experiments, all mice immunized with DEGDA died after the booster injection. Mice receiving OVA in combination with HEMA, TEGDMA, or EMA developed a higher immunoglobulin G anti-OVA antibody levels compared to the group immunized with OVA alone. We could not demonstrate any significant difference in antibody levels among the mice receiving the various methacrylate/acrylate monomers. The different monomers affected the production, increase and decrease, of different cytokines in vitro but resulted also in vivo in increased antibody production and T-cell activity.

2-Hydroxyethyl methacrylate inflammatory effects in human gingival fibroblasts

AIM

To investigate the inflammatory response in human gingival fibroblasts (HGFs) treated with a relatively low 2-hydroxyethyl methacrylate (HEMA) concentration by studying reactive oxygen species (ROS) production, cyclooxygenase-2 (COX-2) and tumour necrosis factor-alpha (TNF-α) gene expression, and prostaglandin E2 (PGE₂) release.

METHODOLOGY

Cultured HGFs were exposed to 3 mmol L⁻¹ HEMA for 0, 24 or 96 h. ROS production was investigated by flow cytometry; TNF-α and COX-2 gene expression was determined by RT-PCR, and prostaglandin E2 production was detected by an enzyme immunoassay.

RESULTS

After 24- or 96-h HEMA incubation, ROS levels were approximately eightfold and elevenfold higher than controls, whilst COX-2 gene expression was approximately twofold or fourfold higher than controls, respectively. Twenty-four-hour exposure enhanced TNF-α mRNA levels by approximately 66%, whilst after 96-h incubation, TNF-α gene expression was fivefold higher than controls. Ninety-six-hour HEMA treatment increased PGE₂ concentration in the culture medium by around 17% compared with controls.

CONCLUSIONS

2-Hydroxyethyl methacrylate treatment (3 mmol L⁻¹) induced an inflammatory response in HGFs modulated by ROS production, as well as by the increase in TNF-α and COX-2 gene expression and by PGE₂ release.