Mercury in dental restoration: is there a risk of nephrotoxicity?
BACKGROUND
Concern has been voiced about exposure to mercury (Hg) from dental amalgam fillings, and there is a need to assess whether this leads to signs of nephrotoxicity.


METHODS
A total of 101 healthy adults (80 males and 21 females) were included in this study. The population as grouped into those having amalgam fillings (39 males and 10 females) and those without (41 males and 11 females). Hg was determined in blood, urine, hair and nails to assess exposure. Urinary excretion of beta2-microglobulin (beta2M), N-acetyl-beta-D-glucosaminidase (NAG), gamma-glutamyltransferase (gammaGT) and alkaline phosphatase (ALP) were determined as markers of tubular damage. Albuminuria was assayed as an early indicator of glomerular dysfunction. Serum creatinine, beta2M and blood urea nitrogen (BUN) were determined to assess glomerular filtration.


RESULTS
Hg levels in blood and urine were significantly higher in persons with dental amalgam than those without; in the dental amalgam group, blood and urine levels of Hg significantly correlated with the number of amalgams. Urinary excretion of NAG, gammaGT and albumin was significantly higher in persons with dental amalgam than those without. In the amalgam group, urinary excretion of NAG and albumin significantly correlated with the number of fillings. Albuminuria significantly correlated with blood and urine Hg.


CONCLUSIONS
From the nephrotoxicity point of view, dental amalgam is an unsuitable filling material, as it may give rise to Hg toxicity. Hg levels in blood and urine are good markers of such toxicity. In these exposure conditions, renal damage is possible and may be assessed by urinary excretions of albumin, NAG, and gamma-GT.
Mortada
Wael L
WL
Urology and Nephrology Center, Mansoura University, Faculty of Science, Egypt.
Sobh
Mohamed A
MA
El-Defrawy
Mohamed M
MM
Farahat
Sami E
SE
D000118:Acetylglucosaminidase / Q000652:urine*; D000328:Adult; D000469:Alkaline Phosphatase / Q000652:urine*; D015415:Biomarkers / Q000097:blood / Q000652:urine; D003404:Creatinine / Q000097:blood*; D003723:Dental Amalgam / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000209:etiology / Q000652:urine; D008297:Male; D008628:Mercury / Q000009:adverse effects* / Q000097:blood / Q000652:urine; D001613:beta 2-Microglobulin / Q000097:blood / Q000652:urine*; D005723:gamma-Glutamyltransferase / Q000652:urine*
D015415:Biomarkers; D001613:beta 2-Microglobulin; D003723:Dental Amalgam; D003404:Creatinine; D005723:gamma-Glutamyltransferase; D000469:Alkaline Phosphatase; D000118:Acetylglucosaminidase; D008628:Mercury