Cell Mediated Immune Affection Among Dental Staff Exposed to Mettalic Mercury

For more than a century and half, silver/mercury amalgam fillings have been used in dental practice as the preferred tooth filling material. Currently, occupational exposure of dental staff to mercury vapor released from the amalgam, has been an issue of concern because of its possible adverse outcomes. Aim: The aim of this work was to determine the mercury body burden in dental staff exposed to elemental mercury during their work course and the relation of this burden with exposure conditions. Besides, the study aimed at investigating the potential impact of metallic mercury vapor on the cellular immune system and cytokine (IL6) as a possible mechanism of its immunotoxicity. Study Population: The study population consisted of group of dental staff (n=39) and a matched control group (n=42). Dental staff group was further subdivided into a group of dentists (n=21), and a group of nurses (n=18). Methods: Each individual was subjected to detailed occupational and medical history taking and estimation of urinary mercury (U-Hg) and blood mercury (B-Hg) as indicators of mercury of body burden and exposure, respectively. Measurement of IL-6, CD3, CD4 and CD8 as immunological parameters. Results: The study revealed statistically significant higher U-Hg and B-Hg levels in the dental staff compared to their controls. This elevation of mercury body burden was associated with marked significant reduction in CD3, CD4, and CD8 and increase in Il-6 among exposed group compared to the control group. Recommendations: Exposure to mercury vapour produced in operating rooms is the main concern for dentists. Every effort should be made to avoid contact with mercury vapour if possible by using barrier techniques, reducing the temperature of the operating room and of the amalgam restoration. Air conditioning and proper ventilation of the operating room, the use of coolant sprays, good suction and proper handling of amalgam waste is recommended.