Evaluation of the Release of Monomers From Composite Bonding Resins in Orthodontics

Plain-language summary

In recent decades, the field of public health has become increasingly interested in endocrine disruptors, and their effects on humans. Indeed, various scientific studies have highlighted an evolution in the frequency of pathologies due to these substances, affecting in particular the reproductive organs. Many concerns are expressed about the impact of these substances, present in the environment or in consumer products, on the hormonal system. Effects have been observed in animals in experimental studies, but the question of extrapolating these results to humans arises, especially for exposures at low doses. In orthodontics, the composite is the material of choice mainly for bonding fasteners, then bonding a compression wire. These composite materials contain many monomers. The polemics launched on Bisphenol A and the questions of our patients on the nature and toxicity of dental products oblige us to reflect on their harmfulness after their placement in the oral cavity. Many questions arise today about dental composites and their participation in the release of endocrine disruptors. Indeed, Bisphenol A is used in the manufacturing process of the monomers of orthodontic composites, as precursors of Bis-GMA and Bis-DMA. The objective of this study is to search for the presence of BPA, TEGDMA, BisGMA, BisDMA and UDMA monomers, and to carry out the samples and their analysis at different clinical times (at T0, after the removal of orthodontic attachments, after the placement of the compression, one hour later, one week later, one month later and 6 months later) and the comparison of this quantification to that without orthodontic restraint. Studies have been performed in vitro, but very little in vivo. In addition, these studies are only carried out on release at the time of installation, but few are interested in the continuation of the phenomenon over time and the deterioration of the composite. Although the short-term toxicity of BPA is low, its dangerousness lies in its potential endocrine disrupting effect and which can induce long-term chronic toxicity. Compounds such as TEGDMA, BisGMA, BisDMA and UDMA differ greatly in their volatility due to their different chemical structures as well as in their stability in saliva; Many methods have been developed to study each monomer individually or to study them simultaneously using different analytical techniques to determine their presence and to quantify them after their release from dental products. The analysis of the samples is carried out by liquid chromatography (HPLC).

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