Reproductive toxicity evaluation of the dental resin monomer bisphenol a glycidyl methacrylate (CAS 1565-94-2) in mice

Light-curable urushiol enhanced bisphenol A glycidyl dimethacrylate dentin bonding agent

OBJECTIVES

The low durability of composite resin restorations can be attributed to the degradation of the resin dentin bonding interface. Owing to the presence of hydrophilic components in the adhesive, the integrity of the resin dentin bonding interface is easily compromised, which, in turn, leads to a reduction in bond strength. The hydrophilic nature of the adhesive leads to water sorption, phase separation, and leaching of the resin component. Therefore, hydrophobic adhesives could effectively be used to stabilize the integrity and durability of the resin dentin bonding interface.

METHODS

We synthesized a novel hydrophobic dentin adhesive by partially replacing bisphenol A glycidyl dimethacrylate (Bis-GMA) with a light-curable urushiol monomer. The properties of the produced adhesive, including the degree of conversion, viscosity, contact angle, water sorption/solubility, and mechanical strength, were comprehensively examined and compared to those of the commercially adhesive Adper Single Bond2 as a positive control. The adhesive properties were determined using microtensile bond strength measurements, laser confocal microscopy, scanning electron microscopy observations, and nanoleakage tests. Finally, the novel adhesive was subjected to biocompatibility testing to determine its potential cytotoxicity.

RESULTS

At a light-curable urushiol content of 20 %, the synthesized adhesive exhibited high degrees of conversion and hydrophobicity, low cytotoxicity, good mechanical properties, and outstanding adhesive strength.

CONCLUSIONS

The introduction of the light-curable urushiol into dentin adhesives can significantly enhance their hydrophobic, mechanical, and bonding properties, demonstrating potential to significantly improve restoration longevity.

CLINICAL SIGNIFICANCE

The integration of light-curable urushiol has endowed the experimental adhesives with several enhanced functionalities. These notable benefits underscore the suitability of this monomer for expanded applications in clinical practice.

Elution from direct composites for provisional restorations

Purpose To assess elution from direct composite materials for provisional restorations and compare them with elution from direct restorative composites for permanent restorations.Methods Two dual-cure (Integrity Multi-Cure and Tempsmart DC) and two self-curing composites (Protemp 4 and Structur 3) were used, with Essentia serving as a reference. Cylindrical specimens (n=20) were cured according to the manufacturer's instructions; the dual-cure materials were prepared in both self- and dual-curing modes. Elution experiments were performed using water and absolute ethanol. The samples were incubated at 37 °C for either 24 h or four weeks; the extraction solvents were refreshed weekly. The eluted BisEMA (-3 / -6 / -10), BisGMA, CQ, UDMA, and TEGDMA were quantified using UHPLC-MS/MS.Results Monomer elution was detected in all provisional composites at 24 h and four weeks, but the amounts released did not exceed those released by the reference composite. When prepared in self-curing mode, Integrity Multi-Cure exhibited significantly higher elution of BisEMA-3, -6, and -10 in ethanol both after 24 h and cumulatively after four weeks. Self-cured Tempsmart DC released significantly more CQ, TEGDMA, and UDMA in both water and ethanol after immersion for 24 h and four weeks, along with significantly more BisGMA in ethanol both after 24 h and four weeks comparison to dual-cured Tempsmart DC (two-way ANOVA, post-hoc Tukey, P < 0.05).Conclusions Provisional composite materials did not elute higher amounts of monomers than a restorative composite. Dual-cured materials, prepared in the self-curing mode, show a trend towards higher monomer elution.

Evaluation of the toxic potential of Bisphenol-A glycidylmethacrylate (BisGMA) on the third instar larvae of transgenic Drosophila

Introduction

In the present study the cytotoxic and genotoxic effects of Bisphenol-A glycidyl methacrylate (BisGMA) was studied on the third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ)Bg9.

Materials and methods

The concentration of BisGMA i.e. 0.005, 0.010, 0.015 and 0.020 M were established in diet and the larvae were allowed to feed on it for 24 h.

Results

A dose dependent significant increase in the activity of β-galactosidase was observed compared to control. A significant dose dependent tissue damage was observed in the larvae exposed to 0.010, 0.015 and 0.020 M of BisGMA compared to control. A dose dependent significant increase in the Oxidative stress markers was observed compared to control. BisGMA also exhibit significant DNA damaged in the third instar larvae of transgenic D. melanogaster (hsp70-lacZ)Bg9 at the doses of 0.010, 0.015 and 0.020 M compared to control.

Conclusion

BisGMA at 0.010, 0.015 and 0.020 M was found to be cytotoxic for the third instar larvae of transgenic D. melanogaster (hsp70-lacZ) Bg9.

Do resin-based composite CAD/CAM blocks release monomers?

OBJECTIVE

The present study aimed to identify and quantify the elution of monomers of five different resin-based CAD/CAM blocks (RCBs) using HPLC.

METHODS

Five different RCBs were used in the study: GC Cerasmart (CS), Voco Grandio blocs (GR), 3M Lava Ultimate (LU), Shofu Block (SB), and Vita Enamic (VE). Fifteen samples from each material were prepared using a low-speed precision diamond saw (ISOMET Buehler, Lake Bluff, IL, USA) at 5 × 5 × 4 mm size. After the preparation of samples, an extraction solution was mixed with %75/%25 ethanol/water. The samples were stored in the amber-colored bottles during three different immersed periods as 1 h, 24 h, and 90 days (n = 5). After immersion, 0.5 ml solutions were taken from each bottle and analyzed using HPLC.

RESULTS

A total of 16.7 μg/ml of monomers from SB, 13.4 μg/ml of monomers from GR, 13.2 μg/ml of monomers from CS, and 6.7 μg/ml of monomers from LU were found after 3-m immersion. TEGDMA after 3-m of immersion was only released from the SB group, and also BisEMA was released from the CS group. Among the specimens immersed for 1 h, UDMA was released the least from the LU group and the most from the GR group (p < 0.05). Correspondingly, 24 h and 3 m after immersion, the highest release of monomers was found in the GR (p < 0.05).

CONCLUSIONS

When the monomer release from RCBs was evaluated, it was shown that these materials released methacrylate-based monomers except VE, especially if they were kept in a solvent solution for a long time such as 3 m.

CLINICAL SIGNIFICANCE

The novel resin-based CAD/CAM blocks might monomer release, which may cause cytotoxic effects. But, the detected amount of monomer release is below the estimated daily limit.

Synthesis and characterization of a novel resin monomer with low viscosity

OBJECTIVE

In this study, we designed and synthesized a novel macromolecule (tetramethyl bisphenol F acrylate, TMBPF-Ac) with low viscosity, excellent mechanical properties, and good biocompatibility. It could be used as a monomer for dental resin composites, which could reduce the risk of human exposure to bisphenol A derivatives in the oral environment. In addition, the monomer could be used without diluent, thereby avoiding the negative effect of a diluent METHODS: TMBPF-Ac was synthesized by a multistep condensation reaction. Its structure was confirmed by ¹H NMR spectra. Different resin mixtures were prepared, and then a number of performance and cytotoxicity tests were performed on these specimens.

RESULTS

¹H NMR spectra showed that the structure of TMBPF-Ac was in accordance with the design. The viscosity of TMBPF-Ac was obviously lower than that of bisphenol-A diglycidyl methacrylate. The three kinds of resins used in this study were in line with ISO 4049:2009 and ISO 10993-5:2009. TMBPF-Ac-based resin had better physical and biological properties.