[Mercury impregnation in dentists and dental assistants in Monastir city, Tunisia].
BACKGROUND
The property of mercury to amalgamate with other metals is used to create a material for filling teeth. This material remains the cheapest and most efficient in tooth restoration. Mercurial toxicity has been documented since Antiquity but the metal remains widely used in some countries. This study compared mercury impregnation in dentists and dental assistants in Monastir (Tunisia) to another population not exposed professionally.


METHODS
A cross-sectional study was made on 52 dentists and dental assistants working in private offices and in the stomatology unit of the Monastir teaching hospital, with a control group of 52 physicians and nurses working in the Monastir Fattouma Bourguiba hospital. The groups were paired according to age and gender. The study lasted three months. A questionnaire investigated the socioprofessional features of the study population, non professional mercury exposure, work environment, the various amalgam handling and preparation techniques, and preventive hygiene measures. Urinary and salivary sampling was performed so as to prevent any accidental mercurial contamination. Mercury level was assessed by atomic absorption spectroscopy in an automatic sampler, urine creatinine with Jaffé's colorimetric reaction. The results of mercury level assessment were expressed in microg/g of creatinine, salivary mercury in mug/l. The statistical analysis was made with the Epi.info 6 software. Khi(2) and Fisher tests were used to compare qualitative variables. The ANOVA test was used to compare averages with a statistic significance threshold at 0.05.


RESULTS
Sixty-one percent of individuals with risk exposure worked in a dental clinic. Bruxism and onychophagia were more important in the control group with a significant statistical difference (respectively, p=0.01 and p<0.0001). The urinary and salivary mercury levels were significantly increased in the exposed group, with respective values of 20.4+/-42.4microg/g of creatinine and 10.6+/-13.02microg/l versus 0.04+/-0.3microg/g of creatinine and 0microg/l in the control group. Disposing of amalgam waste was inadequate in 94% of the cases. The variation of mercury in urine was significantly influenced by the presence of fabric curtains (p=0.04). Eating lunch at meals at the work place was also linked to a significant increase of mercury levels in urine (p=0.04). The storage mode of mercury in open containers was a significant factor for variation of mercury level (p=0.03).


CONCLUSIONS
Most dentists' private offices in Monastir do not comply or comply weakly with prevention measures linked to risk of mercury poisoning. Awareness campaigns were launched as well as actions for the improvement of work conditions: efficient aspiration of offices containing fixed sources of mercury, adequate storage of mercury and waste, and compliance to occupational hygiene rules.
Service de médecine du travail et de pathologies professionnelles, CHU de Monastir, Tunisie. chaari_ne@yahoo.fr
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N
Chaari
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A
Kerkeni
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Saadeddine
F
F
Neffati
T
T
Khalfallah
M
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Akrout
D000328:Adult; D002012:Bruxism / Q000150:complications; D016022:Case-Control Studies; D003124:Colorimetry; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D003723:Dental Amalgam / Q000633:toxicity*; D003726:Dental Assistants; D003770:Dental Offices; D003796:Dental Service, Hospital; D018057:Dental Waste; D003815:Dentists; D004781:Environmental Exposure; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D008297:Male; D008505:Medical Staff, Hospital; D017744:Medical Waste Disposal; D008628:Mercury / Q000032:analysis / Q000633:toxicity* / Q000652:urine; D009259:Nail Biting / Q000009:adverse effects; D009741:Nursing Staff, Hospital; D016273:Occupational Exposure; D016272:Occupational Health; D012307:Risk Factors; D012463:Saliva / Q000737:chemistry; D013054:Spectrophotometry, Atomic; D014416:Tunisia; D017132:Workplace
D018057:Dental Waste; D017744:Medical Waste Disposal; D003723:Dental Amalgam; D003404:Creatinine; D008628:Mercury