## 1 Introduction
Mercury can be released from dental amalgams through three principal mechanisms: mechanical wear, the dissolution or volatilization of elemental mercury, and electrochemical degradation [28; 29]. During the placement or removal of amalgam restorations, patients may be exposed to minute amounts of mercury vapors and particulates. The extent of elemental mercury emission into the oral cavity has been reported to be directly proportional to the number of amalgam-covered surfaces [29]. Moreover, mercury and other constituents of amalgam restorations can be absorbed into the body, potentially triggering allergic reactions in susceptible individuals. For the vast majority of patients, routine exposure to amalgam does not adversely affect systemic or oral health. However, certain symptoms--such as discoloration of the oral mucosa, amalgam tattoos, lichen planus, mood disturbances including irritability and depression, paresthesia of the extremities, noturia, persistent fatigue, cold intolerance, bloating, cognitive impairment, anger, and constipation--have been sporadically documented [30]. Additionally, research has identified a significant association between urinary mercury concentrations in children and both the quantity and duration of their amalgam restorations [25]. The World Health Organization estimates that the typical daily mercury absorption from amalgams ranges between 1 and 22 ug, with the majority of individuals being exposed to doses under 5 ug per day. However, there is substantial variability, with the upper end reaching as much as 100 \(\upmu\)g per day, particularly in association with gum chewing. Factors influencing exposure include the total surface area of the amalgam, its physical and chemical composition, mechanical stresses from chewing and bruxism, proximity to other metals, and oral conditions such as temperature, pH, and negative air pressure. The FDA's current regulations regarding amalgam assume an exposure range of 1 to 5 \(\upmu\)g per day [31]. Recent estimates, based on pharmacokinetic parameters applied to steady-state plasma levels in individuals with amalgam, report an average intake between 5 and 9 \(\upmu\)g per day [32]. In a study conducted by [PERSON] et al., which examined the relationship between urinary mercury excretion and the number of amalgam surfaces, it was estimated that 10 amalgam surfaces would result in a 1 \(\upmu\)Hg/L increase in urinary mercury levels [33]. Dental amalgam is a primary source of elemental mercury in the general population. Numerous studies have demonstrated a correlation between urinary mercury levels and the number of dental amalgam fillings in children [25; 34; 35]. In accordance with in vivo studies, it has been determined that mercury released from dental amalgam restorations ranges between 0.014 and 0.016 \(\upmu\)g/mm\({}^{2}\)[36]. According to the World Health Organization, the recommended maximum daily intake of mercury is 40 \(\upmu\)g per kilogram of body weight, while the provisional tolerable weekly intake limit is estimated at 300 \(\upmu\)g of total mercury and 200 \(\upmu\)g of methylmercury for an individual weighing 60 kg [37]. Extensive efforts have been made to quantify mercury release into body fluids, particularly saliva, with estimates suggesting a daily release of between 0.2 and 3.2 mg from dental amalgam [38; 39]. In another study, unstimulated saliva collected from five subjects over 40 min revealed total mercury levels ranging from 1.8 to 13.8 ng Hg/min [40]. Furthermore, the mercury vapor exposure limit set by the Occupational Safety and Health Administration in the United States is 100 times higher than the exposure level encountered by an individual with nine dental amalgam restorations [41]. The loss of metal ions and atoms from dental amalgams is a significant issue that has been extensively discussed in numerous previous investigations [20; 21; 31]. Mercury vapor can be dissolved in saliva, swallowed, and absorbed through the mucous membrane and the gastrointestinal system.