Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04459013 |
| Other study ID # |
APHP200328 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
June 3, 2020 |
| Est. completion date |
December 16, 2020 |
Study information
| Verified date |
November 2023 |
| Source |
Assistance Publique - Hôpitaux de Paris |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial 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).
Description:
For several years, we have been wondering about the potential deleterious effects of
bisphenol A (BPA) on our organism. Known as an endocrine disruptor, its action has been
demonstrated at different levels of the human body and by different mechanisms. Its endocrine
activity is due to its structure close to that of estradiol. Cytotoxicity is the property of
a chemical or biological agent to be toxic to cells, possibly destroying it. Bisphenol A
(BPA) has received increasing attention in recent years. It is used in the monomer
manufacturing process of composites customary in orthodontics, as a precursor of Bis-DMA and
Bis-GMA, but is not normally found in pure form in these composites. In the mouth, these
materials are subject to numerous degradation constraints, initial and long-term: thermal
variations, pH change, mechanical wear, enzymatic, bacterial and salivary attack. They are
therefore responsible for the possible release of BPA, found in many human biological fluids,
including saliva. The monomers present in the composite resins are released in 2 stages:
immediate release where the non-polymerized monomers are found in the saliva for a few hours
after the treatment, delayed release where the monomers can be released following the
treatment by the various mechanisms of wear and degradation of the composite. If the BPA is
mainly released in saliva within three hours after the establishment of the dental
restoration, the long-term release remains to be determined, which explains the patient's
follow-up time of 6 months.
The main objective of this research is the quantification of the Bisphenol A monomer released
during the placement of a mandibular orthodontic compression in order to raise awareness
among professionals and the comparison of this quantification to that without orthodontic
restraint. The study relates to the analysis of patients followed in the dental department at
the Pitié Salpetrière hospital. The study briefing note will be presented to patients during
the visit. Non-opposition will be collected and notified in the patient's medical file after
a 15-day cooling-off period.
The salivary samples will be collected at 5 defined times: before removal of the orthodontic
brackets (T0), after removal (T1), just after application of the compression (T2), then at
one hour (T3), one month (T4) and 6 months (T5), as part of the end of their orthodontic
treatment. Control samples will be taken from patients who do not have a composite
restoration in their mouth. The inclusion criteria are patients undergoing orthodontic
treatment (multi-attachment device) with planned debagging and requiring compression with
mandibular bonded wire from canine to canine and maxillary groove, without composite
restoration in the mouth, with good hygiene and not gingival inflammation. The exclusion
criteria are patients requiring maxillary bonded compression, with composite restoration in
the mouth, carious lesions, smokers, with chronic pathologies and / or drugs, with chronic
exposure to Bisphenol A (construction sites, service stations ... ). The composite cartridges
will be weighed before and after their use, to have the exact quantity of material placed in
the mouth. For laying the compression wire, the protocol will also be identical to the
bonding protocol in adhesive dentistry.
The samples are analyzed by liquid chromatography (HPLC) on the Bioprofiler platform
(Metabolism Platform) of the Functional and Adaptive Biology Unit - CNRS UMR 8251 at Paris
Diderot University.
The analytical method chosen for the identification and quantification of the compounds is
high pressure liquid chromatography (HPLC). This method allows the separation of the
constituents of a very complex mixture. The HPLC consists of two pumps which maintain a
mobile phase under pressure in a column (stationary phase). The sample is injected into the
circulation system of the mobile phase and passes into the column where the different
constituents are more or less retained. The nature of the mobile phase and of the column
allows separation according to the physicochemical properties of the constituents of a
mixture.
Developments and optimizations of extraction and dosage methods allowing the analysis of the
release of bisphenols by orthodontic materials in saliva samples were carried out on this
platform.
