In experimental studies, chewing gum has been shown to increase the release rate of mercury vapor from dental amalgam fillings. The aim of the present study was to investigate the influence of long-term frequent chewing on mercury levels in plasma and urine. Mercury levels in plasma (P-Hg) and urine (U-Hg), and urinary cotinine were examined in 18 subjects who regularly used nicotine chewing gum, and in 19 referents. Age and number of amalgam surfaces were similar in the two groups. Total mercury concentrations in plasma and urine were determined by means of cold vapor atomic absorption spectrometry. Urinary cotinine was determined by gas chromatography-mass spectrometry. The chewers had been using 10 (median) pieces of gum per day for the past 27 (median) months. P-Hg and U-Hg levels were significantly higher in the chewers (27 nmol/L and 6.5 nmol/mmol creatinine) than in the referents (4.9 nmol/L and 1.2 nmol/mmol creatinine). In both groups, significant correlations were found between P-Hg or U-Hg on the one hand and the number of amalgam surfaces on the other. In the chewers, no correlations were found between P-Hg or U-Hg and chewing time per day or cotinine in urine. Cotinine in urine increased with the number of pieces of chewing gum used. The impact of excessive chewing on mercury levels was considerable.
Abraham JE, Svare CW, Frank CW (1984). The effect of dental amalgam restorations on blood mercury levels. J Dent Res63:71-73.
2.
Acgih (1994-1995). Threshold limit values for chemical substances and physical agents, and biological exposure indices.
3.
Akesson I., Schutz A., Attewell R., Skerfving S., Glantz P.-O (1991). Status of mercury and selenium in dental personnel: Impact of amalgam work and own fillings. Arch Environ Health46:102-109.
4.
Aronsson AM, Lind B., Nylander M., Nordberg M. (1989). Dental amalgam and mercury. Biol Metals2:25-30.
5.
Barregard L. (1993). Biological monitoring of exposure to mercury vapor . Scand J Work Environ Health19(Suppl 1):45-49. Barregard L., Sallsten G., Jarvholm B. (1995). People with high mercury uptake from their own dental amalgam fillings . Occup Environ Med52:124-128.
6.
Bergdahl IA, Schutz A., Hansson GA (1995). Automated determination of inorganic mercury in blood after sulfuric acid treatment, using cold vapour-atomic absorption spectrometry and an inductively heated gold trap. Analyst120:1205-1209. Berglund A. (1990). Estimation by a 24-hour study of the daily dose of intra-oral mercury vapor inhaled after release from dental amalgam. J Dent Res69:1646-1651.
7.
Berglund A. (1993). An in vitro and in vivo study of the release of mercury vapor from different types of amalgam alloys. J Dent Res72:939-946.
8.
Bjemer B., Sundberg H. (1994). Vuxenbefolkningens tandhalsa i Sverige. Tandläkartidningen16:1005-1018 (in Swedish). Bjorkman L., Lind B. ( 1992). Factors influencing mercury evaporation rate from dental amalgam fillings. Scand J Dent Res100:354-360.
9.
Bolewska J., Holmstrup P., Moller-Madsen B., Kenrad B., Danscher G. (1990). Amalgam associated mercury accumulations in normal oral mucosa, oral mucosal lesions of lichen planus and contact lesions associated with amalgam. J Oral Pathol Med19:39-42.
10.
Clarkson TW (1992). Principles of risk assessment. Adv Dent Res6:22-27.
11.
Einarsson Ö., Lindstedt G., Bergstrom T. (1984). A computerized automatic apparatus for determination of mercury in biological samples. J Autom Chem6:74-79.
12.
Freden H., Hellden L., Milleding P. (1974). Mercury content in gingival tissues adjacent to amalgam fillings. Odont Revy25:207-210.
13.
Hahn LJ, Kloiber R., Leininger RW, Vimy MJ, Lorscheider FL (1990). Whole-body imaging of the distribution of mercury released from dental fillings into monkey tissues. FASEB4:3256-3260. Horstedt-Bindslev P., Bolewska JE, Arenholt-Bindslev D., Danscher G. (1991). Dentinal transport of mercury from dental silver
14.
amalgam restorations. Progr Histo- Cytochem23:321-326. Klaassen CD (1986). Principles of toxicology . In: Casarett and Doull's toxicology. Klaassen CD, Amdur MO, Doull J, editors. 3rd ed. New York: Macmillan Publishing Co., pp. 11-32. Lentz DL, Buchanan JT, Zardiackas LD, Alexander JJ (1989). Mercury penetration into the pulp of teeth restored with amalgam. Am J Dent2:171-173.
15.
Langworth S., Elinder C-G., Gothe C-J., Vesterberg O (1991). Biological monitoring of environmental and occupational exposure to mercury. Int Arch Occup Environ Health63:161-167. Molin M., Bergman B., Marklund SL, Schutz A., Skerfving S. (1990). Mercury, selenium and glutathione peroxidase before and after amalgam removal in man. Acta Odontol Scand48:189-202. Moller B. (1978). Reaction of the human dental pulp to silver amalgam restorations. Swed Dent J2:93-97.
16.
Ngim CH, Foo SC, Boey KW, Jeyaratnam J. (1992). Chronic neurobehavioural effects of elemental mercury in dentists. Br J Ind Med49:782-790.
17.
Nylander M., Friberg L., Lind B. ( 1987). Mercury concentrations in the human brain and kidneys in relation to exposure from amalgam fillings. Swed Dent J11:179-187.
18.
Olsson S., Bergman M. (1992). Daily dose calculations from measurements of intra-oral mercury vapor. J Dent Res71:414-423. Olsson S., Berglund A., Pohl L., Bergman M. (1989). Model of mercury vapor transport from amalgam restorations in the oral cavity. J Dent Res68:504-508.
19.
Ott Khr, Krafft T., Kroncke A., Schaller K-H., Valentin H., Weltle D. (1986). Untersuchungen zum zeitlichen verlauf der quecksilberfreisetzung aus amalgamfullungen nach dem kauen. Dtsch Zahnärztl Z41:968-972.
20.
Patterson JE, Weissberg BG, Dennison PJ (1985). Mercury in human breath from dental amalgams. Bull Environ Contam Toxicol34:459-468.
21.
Ramstrom LM (1994). Use of nicotine replacement therapy with and without prescription. In: Future directions in nicotine replacement therapy. Proceedings, Paris , 1993. Chester: Adis International Limited, pp. 28-34.
22.
Schiele R., Hilbert M., Schaller K-H., Weltle D., Valentin H., Kroncke A. (1987). Quecksilbergehalt der pulpa von ungefüllten und amalgamgefüllten zahnen. Dtsch Zahnärztl Z42:885-889. Skare I., Bergstrom T., Engqvist A., Weiner JA (1990). Mercury exposure of different origins among dentists and dental nurses. Scand J Work Environ Health16:340-347.
23.
Skarping G., Willers S., Dalene M. (1988). Determination of cotinine in urine using glass capillary gaschromatography and selective detection, with special reference to the biological monitoring of passive smoking. J Chrom454:293-301.
24.
Snapp KR, Boyer DB, Peterson LC, Svare CW (1989). The contribution of dental amalgam to mercury in blood. J Dent Res68:780-785.
25.
Soleo L., Urbano ML, Petrera V., Ambrosi L. (1990). Effect of low exposure to inorganic mercury on psychological performance. Br J Ind Med47:105-109.
26.
Vimy MJ, Lorscheider FL (1985). Serial measurements of intra-oral air mercury: estimation of daily dose from dental amalgam. J Dent Res64:1072-1075.
27.
Willers S., Attewell R., Bensryd I., Schutz A., Skarping G., Vahter M. (1992). Exposure to environmental tobacco smoke in the household and urinary cotinine excretion, heavy metals retention, and lung function. Arch Environ Health47:357-363. World Health Organization (WHO) (1991). Environmental health criteria 118. Inorganic mercury. Geneva: WHO.
