A A

La position alambiquée du Scenihr sur le mercure dentaire – avec le RES et NAMD

18 Sep 2014

Communiqués, Medias

Communiqué de presse commun – Michèle RIVASI, députée européenne, le « Réseau Environnement Santé » et « Non au Mercure Dentaire »

Paris, le 18 septembre 2014,

 

Le Comité européen chargé des risques émergents (Scenihr) vient de publier son nouvel avis sur les amalgames dentaires[i]. Certes, les experts ne s’empressent pas de déclarer qu’il faut éliminer au plus vite un dispositif médical qui empoisonne les Européens depuis 150 ans ; mais ils reconnaissent que :

1) Les amalgames dentaires sont de loin la première source d’exposition au mercure des Européens[ii] ;

2) En conséquence, ils sont susceptibles d’induire un dépassement des valeurs d’exposition tolérables[iii] ;

3) Les professionnels de la dentisterie continuent d’être contaminés en proportion du nombre d’amalgames qu’ils posent, et ils sont en moyenne bien plus intoxiqués que la population générale[iv].

Voici qui pourrait largement suffire à justifier l’interdiction du mercure dentaire, dans la mesure où les alternatives sont bel et bien disponibles[v]. Mais le Scenihr continue :

4) Les femmes enceintes porteuses d’amalgames intoxiquent leur bébé à naître[vi] ;

5) Certains patients présentent des symptômes généraux invalidants qui s’améliorent après le retrait de leurs amalgames[vii] ;

6) Les publications montrent un effet délétère du mercure dentaire sur :

a) le système nerveux[viii] ;

b) le système immunitaire[ix] ;

c) le système endocrinien[x] ;

d) les reins[xi].

7) Même si l’état de la science ne permet pas de trancher avec certitude, les amalgames dentaires pourraient favoriser l’autisme, la maladie d’Alzheimer, la maladie de Parkinson, la maladie de Charcot (SLA), la sclérose en plaques  et des neuropathies périphériques[xii] ;

8) Les résultats contradictoires des études épidémiologiques s’expliqueraient du fait que certains individus sont génétiquement plus vulnérables au mercure[xiii] ;

9) Les assistantes dentaires présentent des symptômes neurologiques plus fréquents que la population générale[xiv] et des travaux mettent en lumière que les dentistes souffrent davantage de problèmes rénaux et de troubles neurocognitifs que la population générale[xv].

Selon toute vraisemblance, les vieilles institutions représentant les dentistes, passionnément attachées à leur vieil amalgame, ne retiendront de ce rapport rien d’autre que la conclusion, éminemment contradictoire avec le contenu du rapport : « l’usage actuel de l’amalgame dentaire ne présente aucun risque de maladie systémique[xvi] ».

Pour autant, nous dit le Scenihr, les amalgames ne sont indiqués ni pour les enfants, ni pour les femmes enceintes, ni pour les patients souffrant de maladies du rein ou d’allergie au mercure[xvii].

Alors, pour qui l’intoxication au mercure dentaire est-elle particulièrement indiquée ? Imagine-t-on de rechercher le profil génétique (car plusieurs gènes sont impliqués) de tout patient avant de procéder à la pose d’un amalgame, pour évaluer la vulnérabilité au mercure de chacun d’entre nous ?  C’est tout simplement impossible.

En fait, le Scenihr se défausse : ce sera au praticien de l’expliquer à son patient, en vertu du principe du « consentement éclairé »[xviii]. Nous souhaitons bonne chance au chirurgien-dentiste pour délivrer une information claire à ce sujet.

 


Notes

 

[i] http://ec.europa.eu/health/scientific_committees/consultations/public_consultations/scenihr_consultation_24_en.htm

Toutes les citations ci-dessous sont extraites de ce rapport.

 

[ii] “Based on an estimated daily absorption of total mercury from diet, water and air of 2.6 ?g (WHO 1990, 1991), and the estimated daily absorption of mercury vapour from dental amalgam of 3 – 17 ?g (WHO 1990, 1991), in case of individuals with a large number of amalgam fillings, amalgam fillings may account for 87 % (17 ?g out of 19) of the absorbed total mercury. In individuals with only a few amalgam fillings, this source may account for about 50 % (3 ?g out of 5.6 ?g) of the absorbed total mercury (summarised in ATSDR, 1999).”

 

[iii] “In line with JECFA, the EFSA CONTAM Panel (2012) established a tolerable weekly intake (TWI) for inorganic mercury of 4 ?g/kg b.w., expressed as mercury. […] The EFSA stated that dietary inorganic mercury exposure in Europe does not exceed the TWI. Inhalation exposure of mercury vapour from dental amalgam is likely to increase the internal inorganic mercury exposure. The TWI might be exceeded when a high number of dental amalgam fillings is present.”

 

[iv] “Ritchie et al. (2004) showed that dentists had, on average, urinary mercury levels over 4 times that of control subjects”

“Correlations have been found amongst dentists between urinary mercury levels and the number of hours worked in the surgery (r=0.22, P=0.006) and the number of amalgam restorations placed (r=0.38, P<0.001) and removed (r=0.29, P<0.001) in a week”

“Dental personnel may now be exposed to much less mercury than in the past, in view of the increased use of encapsulated dental amalgam, improvements in amalgam capsule design, the heightened awareness and practice of appropriate dental mercury hygiene measures, and the increasing use of alternative, non-mercury-containing materials (Hørsted-Bindslev 2004).

However, despite trends to reduce exposure to mercury, large, highly statistically significant differences (P<0.0001) may be found between dental personnel (in particular dentists) and controls, with respect of mean urinary, hair (head and pubic) and nail (finger and toe) mercury levels (Morton et al. 2004).”

 

[v] “We conclude that dental health can be adequately ensured by alternative types of restorative material.”

 

[vi] “Mercury vapour, like methyl mercury, is capable of passing the placental barrier. Thus, in a study of 99 mother-child pairs, a strong positive correlation between maternal and cord blood total Hg levels was found (?=0.79; P<0.001). Levels of Hg in the cord blood were significantly associated with the number of maternal amalgam fillings (?=0.46, P<0.001) and with the number of years since the last filling.”

“Brain tissue obtained from 35 children below 5 years of age showed mercury concentrations up to 20 ?g/kg and a significant correlation (p< 0.05) with the mother’s number of amalgam fillings (grouped as less than 2 or more than 10 fillings), and the same correlation was found for kidney cortex samples from 38 foetuses and 35 infants.”

 

[vii] “Follow-up studies on the above-mentioned patient study were recently published (Sjursen et al 2011, Lygre et al 2012). Three years after removal of amalgam fillings most of the health complaints decreased, being statistically significant for taste disturbances, pain from muscles and joints, gastrointestinal complaints, complaints from ear/nose/throat and fatigue.”

 

[viii] “In conclusion, there are some publications that indicate that exposure to mercury may be associated with some decline in the auditory and visual system.”

 

[ix] “In conclusion, inorganic mercury exposure may cause adverse effects on the immune system. However, there is no evidence that autoimmune disease is provoked in humans by mercury exposure from amalgam fillings. In some patients with allergy to mercury, clinical improvement is seen after removal of amalgam fillings. There is some evidence that exposure to mercury influences proinflammatory cytokine levels, but the clinical implications are not clear.”

 

[x] “A study of 75 mother-child pairs from Slovakia showed that exposure to mercury from amalgam and the environment influences thyroid hormone status with e.g. lower thyroxine levels in the mothers. This was correlated to a higher level of thyroid-stimulating hormone in the blood of the newborn children (Ursinyova et al 2012). Although the findings appear meaningful, the clinical implications are not clear.”

 

[xi] “Concerning the urinary system, several studies show that parameters of kidney function may be influenced by mercury from amalgam, but there is no convincing evidence that dental amalgam is associated with a clinically decreased kidney function (decreased renal clearance) in the patients in the short or long term. On the other hand, decreased kidney function (decreased renal clearance) is likely to decrease the ability to eliminate mercury and other substances via the urine.”

 

[xii] “For the neurological system, there is no clear evidence for an increased risk for Alzheimer’s disease, Parkinson’s disease or amyotrophic lateral sclerosis associated with amalgam fillings.

The data are inconclusive for multiple sclerosis.

Likewise, a possible association between amalgam fillings and clinical signs of peripheral neuropathy (paraesthesia) has not been replicated in more recent studies.

The visual and auditory system may be influenced by mercury from amalgam fillings. There is some evidence that indicates that exposure of the mother in early pregnancy to mercury from amalgam may promote the development of autism in the child.”

 

[xiii] “The presence of dental amalgam has been suggested to be associated with a variety of systemic conditions, particularly neurological and psychological/psychiatric diagnoses, including Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis as well as kidney disease.

These possible risks are not substantiated. However, recent studies suggest that the genetic make up may be the cause of a higher mercury internal dose for some individuals, possibly making them more vulnerable to mercury toxicity than the average.”

 

[xiv] “However, even recent studies support the notion that dental assistants have more frequent neurological symptoms, although the association to mercury vapour exposure is uncertain, as the symptoms are generally nonspecific, and other chemical risk factors may have been present (Ngim et al. 1992, Moen et al,2008, Hilt et al., 2009).”

 

[xv] “Dentists were significantly more likely than control subjects to have suffered from disorders of the kidney (6.5 % vs. 0.6 %) but these self-reported symptoms were not significantly associated with their level of mercury exposure as measured in urine (Ritchie et al., 2004).

This difference between dentists and controls remained significant after correcting for multiple comparisons and after adjusting for age and sex using logistic regression (adjusted odds ratio of kidney disorders for dentists: 15.2 (95% CI = 1.8 to 126.3; p = 0.01). As exposure was assessed cross-sectionally, it is possible that the kidney disease resulted in a decreased urinary mercury excretion.

A US study of dentists and dental assistants suggested that an increased prevalence of symptoms of depression, anxiety, and memory was associated with two genetic polymorphisms thought to convey hypersusceptibility to mercury vapour toxicity (Heyer et al 2009).”

“Neurobehavioural tests in 98 dentists (mean age 32, range 24-49) and 54 unexposed controls (mean age 34, range 23-50) consisting of motor speed, visual scanning, visuomotor coordination and concentration, verbal and visual memory, visual memory, and visuomotor coordination speed showed a deficient performance of the dentists compared to the controls.”

 

[xvi] “It is generally concluded that no increased risks on adverse systemic effects have been documented in the general population as a whole and it is considered that the current use of dental amalgam does not pose any risk of systemic disease.”

 

[xvii] “The use of amalgam restorations is not indicated in primary teeth, in patients with mercury allergies, and persons with chronic kidney diseases.”

“Furthermore, to generally reduce the use of mercury-added products in line with the intentions of the Minamata Convention (reduction of mercury in the environment) and under the above mentioned precautions, it can be recommended that for primary teeth, and in pregnant patients, alternative materials to amalgam should be the first choice. This decision should be made after informed consent from the patient or the legal guardians”

 

[xviii] “As a general principle, the relative risks and benefits of using dental amalgam or the various alternatives should be explained to patients to assist them to make informed decisions. This has implications concerning the provision of improved product information from the manufacturers.”

 

Articles similaires :

Tags: , , ,

Leave a Reply

Bienvenue !

Bienvenue sur le site de Michèle Rivasi.


Twitter FaceBook Flux RSS

Rechercher :

Dernière vidéo :
Ad Ad

Suivez-moi sur Facebook!

Associations

Archives