Declining US dental amalgam restorations in US Food and Drug Administration-identified populations: 2017-2023.

BACKGROUND: In light of the Minamata Convention on Mercury and efforts to phase down dental amalgam use, tracking dental amalgam proportions across US Food and Drug Administration (FDA)-identified at-risk populations is of interest to optimize material selection aligned with patient needs. METHODS: A retrospective observational study of Epic's Cosmos electronic health records data set was conducted to calculate the rates of dental amalgam restorations from 2017 through 2023 and stratified using the social vulnerability index (quartile 4 indicates the highest social vulnerability and quartile 1 indicates the lowest) and payer type (Medicare, Medicaid, self-pay, miscellaneous or other). The authors included the following FDA-identified at-risk populations: pregnant people, children younger than 6 years, people with preexisting neurologic conditions, and people with impaired kidney function (n = 1,897,976). RESULTS: The overall rate of dental amalgam restoration placements in the general population declined from 21.8% in 2017 to 4.1% in 2023. Dental amalgam restoration trends, according to social vulnerability index quartile and payer type, decreased consistently across all 4 evaluated populations. Of all the social vulnerability index quartiles, quartile 4, representing the most socially vulnerable group, had the smallest decrease in dental amalgam placement rates among the FDA-identified populations examined. CONCLUSIONS: The study results showed a decreasing trend in dental amalgam restorations from 2017 through 2023 among FDA-identified populations, consistent with the Minamata Convention on Mercury directive for a phasedown in dental amalgam use. Notwithstanding improvements, lingering disparities persist among the most vulnerable population. PRACTICAL IMPLICATIONS: Even within the groups identified as most vulnerable to harm, more targeted interventions and strategies are required to improve treatment among the most socially vulnerable.

Stabilization of residual mercury from gold mining as metacinnabar and cinnabar in ball mills on a pilot scale.

Waste liquid mercury generated as a by-product of the Merrill-Crowe process in gold mining and recovered from mercury-containing waste must be stabilized for secure storage or disposal. This study developed a procedure for mercury stabilization. A ball mill with a 0.5 m3 capacity and a rotational speed of 43 rpm was used to stabilize the residual mercury with sulfur. The treatments were conducted for 30, 60, and 90 min at mercury: sulfur molar ratios of 1.0, 0.8, and 0.67. The ball loading ratio was 7.0 with residual mercury, and the temperature was below 40 °C. The treatment efficiency was evaluated by measuring the concentrations of mercury and other metals using the Toxicity Characteristic Leaching Procedure (TCLP), examining the stabilized residual mercury by X-ray diffraction, and conducting bioassays on Daphnia magna and Lactuca sativa. Principal component analysis (PCA) was performed on the aforementioned variables. The 90-min treatment, with a mercury-to-sulfur molar ratio of 0.67, stabilized mercury mainly as cinnabar compared with the other treatments and presented leachate mercury values below the detection limit <0.003. The leachate from the treatments also showed values of 21.28-38.44 toxic units, classified as very toxic, and generated toxicity, particularly for D. magna, because of the presence of other metals such as Al, Ba, B, Ca, Cu, Cr, Fe, Mn, Ni, and Zn. The variability of the residues in the PCA analysis was explained by the treatment effect and the presence of other metals in the residual mercury. The stabilized residual mercury obtained was classified as non-hazardous and could be stored or disposed of as ordinary waste in a security landfill.

Pin-Retained Amalgam: An Intricate Restorative Case Study.

Amalgam has made dental restorations more manageable, especially in difficult cases, due to its strength, durability, and relatively low cost. There can be pros and cons of each dental material depending on which class of cases it is applied or not applied for, depending on the patient's need, and, of course, the dentist's choice. These materials are used frequently for their hardness and durability and are ideal for extensive restoration procedures. On the other hand, composite resins are considered to be more aesthetic for the profitable areas where esthetics are more important. In contrast, glass ionomer cement is considered to be ideal for low-stress-bearing areas. The following case report of pin-retained amalgam restoration presents an example of its application in practical situations and the factors that must be considered to justify the use of this material against others. This paper explains various factors in considering pin-retained amalgam restorations and the procedure for a better and positive outcome.

Determining the Failure Rate of Direct Restorations-Chart Review versus Electronic Health Record Reports.

Amalgam and composite restorations are used to treat minor dental issues. University of Michigan, School of Dentistry Electronic Health Record (EHR) reports show a 2.31% failure rate for amalgam and 1.14% for composite. Our study aims to determine the true failure rates through manual EHR chart reviews. Patient data from the University of Michigan School of Dentistry were utilized-216 amalgam restorations from 2020 to 2022 and 350 composite restorations in 2021 were searched. We defined failure and retreatment as replacing a restoration with the same material and failure and alternate treatment as replacing restoration with an alternative treatment within one year. The failure rate refers to a combination of replacement with the same and alternative treatment material within one year. For Amalgam: 1.85% failed and were retreated; 7.87% failed and were received an alternate treatment. Composite: 9.71% failed and retreated; 2.86% failed and received alternate treatment. In total anterior composite: 10.5% retreated, 2.6% failed; posterior composite: 9.1% retreated, 3.0% failed. Our study revealed higher restoration failure rates than the reports extracted in the EHR. This highlights the need to foster a culture of precise documentation to align EHR reports with hand-search findings.

The accuracy of Eclipse AXB and AAA dose algorithms with dental amalgam.

High-density materials used for dental restorations are poorly defined in CT imaging due to scanner limitations. Studies have established that Eclipse offers poor agreement with delivered dose in situations involving high-density material. Defining the accuracy of dose algorithms in situations involving high-density overrides would improve clinical outcomes both for target coverage and OAR sparing. Dental amalgam was placed within a solid water phantom and measurements were taken at 1 cm increments beneath the amalgam down to a depth of 6 cm. Exposed film was compared with Eclipse Treatment Planning system (TPS) calculations on a CT of the experimental setup. The amalgam was overridden with a range of HU values and material selections for dose calculation. AXB performs poorly at describing depth dose downstream of Amalgam, regardless of the override material selected. Applying the known mass density with the Anisotropic Analytical Algorithm (AAA) predicts an average of 1.8% and 2.8% for 6 MV and 10 MV beams. The closest agreement achieved using the Acuros XB (AXB) was overriding with stainless steel, which predicted approximately 1.1% and 1.8% above measured dose for 6 MV and 10 MV respectively. Without overriding the density of amalgam, AAA and AXB return depth dose predictions of 7.3% and 5.8% above film measurement for a 6 MV and 7.6% and 6.5% for 10 MV static beams. Applying override options to a clinical case using an anthropomorphic phantom showed using AXB with Stainless Steel as amalgam override returns the same results as AAA with mass density applied for amalgam. Both of these were in close agreement to the TPS.

Neurobehavioral, neurotransmitter and redox modifications in Nauphoeta cinerea under mixed heavy metal (silver and mercury) exposure.

Heavy metals are encountered in nature, and are used in several human endeavors, including in dental fillings. It is well known that the safety of metals depends on their chemical form, as well as the dose and route through which biological systems are exposed to them. Here, we used the Nauphoeta cinerea model to examine the mechanism by which salts of the heavy metals used in dental fillings - silver and mercury - exert their neurotoxicity. Nymphs exposed to heavy metals presented with reduced motor and exploratory abilities as they spent more time immobile, especially in the periphery of a novel object, and covered less distance compared with control nymphs. Exposure to AgNO3 and HgCl2 also exacerbated levels of oxidative stress markers (MDA & ROS) and the neurotransmitter regulators - AChE and MAO, while reducing antioxidant activity markers, both in biochemical (thiol & GST) and RT-qPCR (TRX, GST, SOD, Catalase) examinations, in neural tissues of the cockroach. The observed disruptions in neurolocomotor control, synaptic transmission and redox balance explain how heavy metal salts may predispose organisms to neurological disorders.

Radiofrequency-Induced Heating of Amalgam Restorations and Dental Implants during 1.5T Magnetic Resonance Imaging.

Objectives: This study aimed to evaluate radiofrequency-induced heating of different amalgam restorations and dental implants during 1.5T magnetic resonance imaging (MRI). Materials and Methods: Standardized class I cavities (5 mm long, 3 mm wide, and 3 mm deep) were prepared on the occlusal surface of 45 extracted human third molars. The samples were restored by three different types of amalgam including Cinalux amalgam (non-gamma-2, spherical), GS-80 (non-gamma-2, admix), and GK-110 amalgam (non-gamma-2, admix in silver). As a separate intervention group (G4), five titanium mini drive-lock implants with 2mm diameter and 10mm length were also selected and mounted to the base of the Eppendorf tube with 3mm of the implants extending above the mounting putty. The box containing the specimens was placed parallel to the long axis of the standard head and neck coil of the MRI device (64MHz radio-frequency energy with 25kW amplifier, 1.5T). Temperature fluctuations of the metallic materials in each group were monitored during MRI scans using a calibrated thermometer. One-way ANOVA was used to compare temperature changes among the amalgam groups (P<0.05). Results: Temperature elevations ranged from 0.21°C to 0.70°C in amalgam restorations and from 0.35 to 0.47°C in dental implants. The temperature changes among the three amalgam agents were not statistically significant. Conclusion: According to our findings, the radiofrequency-induced heating of amalgam restorations and dental implants during MRI examination can be considered within acceptable ranges. Therefore, amalgam restorations and dental implants can be categorized as "MR safe" in terms of radiofrequency-induced heating during 1.5 T MRI.

Effect of Polishing and Universal Bonding Application on Mercury Release from Aged Amalgam after Exposure to Bleaching Agents.

Objectives: Teeth bleaching is an accepted and modern treatment in cosmetic dentistry. Bleaching agents may affect amalgam restorations and increase mercury release; therefore, patients are at increased risk of mercury exposure in the body. The aim of this study was to investigate the effect of polishing and universal bonding application on mercury release from aged amalgams exposed to bleaching. Materials and Methods: In this in-vitro experimental study, 64 dental amalgam specimens with dimensions of 3×5×10 were prepared and divided into two experimental and control groups. Each group was further divided into 4 subgroups and received one of the following treatments: no intervention, surface bonding, polishing, or polishing and surface bonding. Subsequently, the samples were immersed in bleaching agent containing 7% hydrogen peroxide and the amount of mercury released after 96h was measured. The results were analyzed by two-way ANOVA and Tukey post hoc tests (α≤0.05). Results: The results showed that the type of solution (P<0.05) and surface treatment (P<0.001) significantly affected the level of mercury release. However, there was no significant interaction between surface treatment methods in the bleaching group and those in the phosphate buffer group (P=0.621). Conclusion: Bleaching agents were found to enhance mercury release from dental amalgam. The application of polishing and universal bonding on amalgam surfaces exhibited significant effects on the reduction of the mercury release.

Survival Rates of Amalgam and Composite Resin Restorations from Big Data Real-Life Databases in the Era of Restricted Dental Mercury Use.

Tooth decay, also known as caries, is a significant medical problem that harms teeth. Treatment is based on the removal of the carious material and then filling the cavity left in the tooth, most commonly with amalgam or composite resin. The consequences of filling failure include repeating the filling or performing another treatment such as a root canal or extraction. Dental amalgam contains mercury, and there is a global effort to reduce its use. However, no consensus has been reached regarding whether amalgam or composite resin materials are more durable, and which is the best restorative material, when using randomized clinical trials. To determine which material is superior, we performed a retrospective cohort study using a large database where the members of 58 dental clinics with 440 dental units were treated. The number of failures of the amalgam compared to composite resin restorations between 2014 and 2021 were compared. Our data included information from over 650,000 patients. Between 2014-2021, 260,905 patients were treated. In total, 19,692 out of the first 113,281 amalgam restorations failed (17.49%), whereas significantly fewer composite restorations failed (11.98%) with 65,943 out of 555,671. This study indicates that composite is superior to amalgam and therefore it is reasonable to cease using mercury-containing amalgam.

Tribochemical silicoating of amalgam promotes effective amalgam-resin repairs.

The purpose of this study was to determine the most effective method for bonding composite resin to artificially aged amalgam. A spherical amalgam alloy was triturated and condensed by hand into cylindrical plastic molds (6 mm in diameter and 4 mm in height) to create 90 specimens, which were then aged for 2 weeks in closed plastic containers at 23°C. The amalgam surfaces underwent 1 of 3 surface treatments (n = 30 per treatment): (1) air particle abrasion (APA) with 50-µm aluminum oxide particles applied with a force of 45 psi from a 10-mm distance, followed by rinsing with deionized water for 60 seconds; (2) APA following the same protocol with subsequent application of a metal primer (Alloy Primer); or (3) coating with 30-µm silica (CoJet) at a force of 45 psi from a 10-mm distance until the surface turned black. Specimens were then treated with 1 of 3 adhesives (n = 10 per adhesive per surface treatment): (1) 2-step total-etch adhesive (OptiBond Solo Plus), (2) 1-step self-etching adhesive (Scotchbond Universal), or (3) dual-cured resin cement (Panavia F 2.0). Each adhesive was applied to the treated amalgam surfaces following its manufacturer's instructions. The specimens were placed in a bonding clamp, and nanocomposite resin columns, 2.38 mm in diameter and 2.00 mm in height, were photocured (40 seconds, 500 mW/cm2) against the treated amalgam surfaces. The specimens were stored for 24 hours in 37°C deionized water and underwent shear bond strength testing at a crosshead speed of 0.5 mm/min. Data were analyzed using 2-way analysis of variance and post hoc analysis with the Tukey test at 95% confidence. The mean (SD) shear bond strength values ranged from 12.3 (1.2) MPa for aluminum oxide-treated surfaces bonded with OptiBond Solo Plus to 25.9 (4.6) MPa for silicoated surfaces bonded with Panavia F 2.0. All bonding agents produced the highest shear bond strength when the amalgam surface was silicoated. These results indicate that composite can be effectively bonded to amalgam via silicoating.

Evaluating the accuracy of Chat Generative Pre-trained Transformer version 4 (ChatGPT-4) responses to United States Food and Drug Administration (FDA) frequently asked questions about dental amalgam.

BACKGROUND: The use of artificial intelligence in the field of health sciences is becoming widespread. It is known that patients benefit from artificial intelligence applications on various health issues, especially after the pandemic period. One of the most important issues in this regard is the accuracy of the information provided by artificial intelligence applications. OBJECTIVE: The purpose of this study was to the frequently asked questions about dental amalgam, as determined by the United States Food and Drug Administration (FDA), which is one of these information resources, to Chat Generative Pre-trained Transformer version 4 (ChatGPT-4) and to compare the content of the answers given by the application with the answers of the FDA. METHODS: The questions were directed to ChatGPT-4 on May 8th and May 16th, 2023, and the responses were recorded and compared at the word and meaning levels using ChatGPT. The answers from the FDA webpage were also recorded. The responses were compared for content similarity in "Main Idea", "Quality Analysis", "Common Ideas", and "Inconsistent Ideas" between ChatGPT-4's responses and FDA's responses. RESULTS: ChatGPT-4 provided similar responses at one-week intervals. In comparison with FDA guidance, it provided answers with similar information content to frequently asked questions. However, although there were some similarities in the general aspects of the recommendation regarding amalgam removal in the question, the two texts are not the same, and they offered different perspectives on the replacement of fillings. CONCLUSIONS: The findings of this study indicate that ChatGPT-4, an artificial intelligence based application, encompasses current and accurate information regarding dental amalgam and its removal, providing it to individuals seeking access to such information. Nevertheless, we believe that numerous studies are required to assess the validity and reliability of ChatGPT-4 across diverse subjects.

Repair versus replacement of defective direct dental restorations: A multinational cross-sectional study with meta-analysis.

OBJECTIVES: When dental practitioners encounter a defective restoration, they are faced with a crucial decision whether to repair or replace it. This study aims to explore international preferences for repair procedures and the clinical steps taken during the repair process. METHOD: An 11-question survey was distributed to dentists across 21 countries via different platforms. The survey comprised two sections: the first included five questions aimed at gathering demographic information, while the second consisted of six questions focusing on participants' practices related to the repair of composite or amalgam restorations A meta-analysis was employed to ascertain the pooled odds ratio of repairing versus replacement. The statistical analysis was carried out using the RevMan 5.3 program and forest plots were generated using the same program to visualize the results. RESULTS: The survey was completed by 3680 dental practitioners. The results indicated a strong tendency to repair defective composite restorations (OR: 14.23; 95 % CI: 7.40, 27.35, p < 0.001). In terms of amalgam, there was a significant tendency to replace the restorations (OR: 0.19; 95 % CI: 0.12, 0.30, p < 0.001). When repairing restorations, the most common protocols were etching with orthophosphoric acid and creating an enamel bevel, regardless of the restorative material used. CONCLUSION: The findings of this study indicate that there exists a knowledge gap among dental practitioners regarding restoration repair. It is imperative that dental practitioners receive proper education and training on restoration repair, to ensure the usage of adequate protocols and restoration survival. CLINICAL SIGNIFICANCE: A significant portion of dental practitioners lack the necessary knowledge and education required for the repair of restorations. Therefore, it is imperative to establish guidelines aimed at enhancing the management of defective restorations, along with protocols for clinical interventions. This includes the incorporation of proper courses in undergraduate, graduate, and continuing education programs.

An Unusual Case of Sinusitis in a Flight Attendant.

Foreign body sinusitis is a rare but important condition that should be taken into account when considering differential diagnoses. In this case report, we present a unique case of sinusitis caused by a foreign body originating from a dental procedure. Additionally, the complexity of the case was compounded by the patient's occupation as a flight attendant. A 49-year-old female flight attendant presented with a two-month history of facial pressure exacerbated by flying. A computed tomography (CT) of her paranasal sinuses confirmed the presence of a radiopaque foreign body near the left maxillary infundibulum, with minimal left ethmoid sinus mucosal thickening. Initially, she elected for non-operative management due to schedule conflicts. Upon follow-up over the next year, she complains of recurring severe facial swelling and congestion. A repeat CT scan shows that she has a dental amalgam that migrated from her left maxilla to the ethmoid infundibulum, lodged between her uncinate process and ethmoid bulla. The patient subsequently underwent foreign body removal. The patient recovered well, and a follow-up CT confirmed the complete removal of the foreign body. This case provides excellent insight into the mechanism of foreign body migration and sinusitis complicated by the unique circumstances of barotrauma associated with regular air travel.

Assessment of Prevalence and Causative Factors for Replacement of Composite and Amalgam Restorations: An Observational Study.

Aim: This study intends to evaluate the frequency and causes of replacement for failed amalgam and composite dental restorations. Methodology: A cross-sectional study comprising female patients with failed permanent composite and amalgam restorations aged 15-60 years old was carried out at the dental clinics of Qassim University. Using a self-structured proforma, demographic data and causes for restoration failure were recorded. The effectiveness of the restorations was assessed by using the Ryge criteria after performing clinical and radiographic examinations. The Statistical Package for Social Science was used for the statistical analysis. Results: It is found that 84.6% of the 299 unsuccessful restorations examined were composite, and 15.4% were amalgam. The main reason for dental failure for both amalgam (95.6%) and composite (93.28%) restorations was secondary caries. Failure of amalgam restoration was largely caused by poor marginal adaptation. With varied incidences between amalgam and composite restorations, typical complaints included discomfort, sensitivity, pain, and food impaction with soreness. The main justification for replacement in amalgam restorations was sensitivity. Repair and replacement rates were similar for amalgam, composite, and mandibular/maxillary restorations. Moreover, 21.1% of individuals overall reported no symptoms, with 8.7% in the amalgam group and 23.3% in the composite group with significant differences (χ2 = 34.28, P = 0.001). Conclusion: According to the current study, secondary caries was found to be the main reason for both amalgam and composite restoration failure. The main problems reported were sensitivity, discomfort, and pain with amalgam showing more sensitivity-related failures.

Catalysis of Indium Ion Electroreduction in the Presence of Acetazolamide in Chlorates(VII) Solutions with Varied Water Activity.

The influence of acetazolamide (ACT) on the kinetics and the mechanism of electroreduction of In(III) ions as a function of changes of the water activity was investigated using electrochemical methods (DC, SWV, CV and EIS, CV). The multi-step mechanism of the electroreduction process should take into account the dehydration step of indium ions and the presence of In-ACT (,,cap-pair" effect) active complexes, mediating electron transfer, located in the adsorption layer. Differences in the electrode mechanism in the presence of ACT were observed for higher chlorates(VII) concentrations (above 4 mol ⋅ dm-3 chlorates(VII)) reflected by a lack of step wise nature of the electrode process. The highest catalytic activity was observed in 4 mol ⋅ dm-3 chlorates(VII).

Elastofibromatous changes in giant cell fibroma and amalgam tattoo: Unusual findings in common oral lesions.

Several cases of elastofibromatous lesion affecting the oral mucosa have been reported. Clinically, these lesions may appear as small exophytic lesions or less often as white lesions. Therefore, fibrous hyperplasia and leukoplakia are not uncommonly considered in clinical differential diagnosis. Microscopically, elastic and fibrous connective tissue deposition is seen. Rarely, elastofibromatous changes can be detected when assessing intraoral lesions, including cysts, salivary gland neoplasms, and epithelial dysplasia. Here we report two oral lesions showing elastofibromatous changes, expanding their clinicopathological spectrum. The first case was a 46-year-old man with a history of asymptomatic nodular lesion on the palate 1 year ago, diagnosed as giant cell fibroma with elastofibromatous changes. The second case was a 79-year-old woman who presented a pigmented and mildly symptomatic lesion on the mandibular alveolar mucosa several months ago, diagnosed as amalgam tattoo associated with elastofibromatous changes.

Association between dental restorations and artefacts on head magnetic resonance images in paediatric patients.

BACKGROUND: Magnetic resonance imaging (MRI) has become an important diagnostic tool for paediatric patients. The association between dental restorations and MRI artefacts/distortions, however, is unclear. AIM: To investigate the association between dental restorations and artefacts in head MRI in children. DESIGN: This retrospective analysis included patients who underwent head MRI and dental examination at Ramathibodi Hospital from January 2015 to March 2021. From dental records and dental radiographs, a dentist reviewed the amount and type of restorative materials used. Two radiologists examined the MRI scans in five sequences for the presence of distortions and quantified the magnitude and grading of any artefacts. RESULTS: Ninety-four patients aged 3-15 years were included. Twenty-four patients who received preformed metal crowns (PMCs) had MRI distortions. Subjects with no restorations or with tooth-coloured material or amalgam restorations or both did not exhibit distortions. The number of PMCs was related to the size of an artefact. Almost all distortions were confined to the oral cavity and maxillary sinus and did not affect the diagnostic brain area. CONCLUSION: Among the commonly used dental restorative materials for children, only PMCs were associated with artefacts on head MRI scans.

Potassium Amyl Xanthate (PAX) as an alternative organic reactive for mercury removal from cyanidation process of amalgamation tailing.

Mercury is the heavy metal that is most difficult to remove from cyanide solution. This situation brings with it many environmental, health and economic problems. This study aims to effectively utilize xanthate by presenting a new strategy for purifying mercury in the cyanidation process of amalgamation residues. In the study, the removal of mercury by precipitation using PAX from cyanidation leach solutions of a well-characterized amalgamation residue was investigated. The dosage of the precipitation reagent is the most important parameter in the removal of mercury. The mercury removal efficiency increases with the increase in the PAX/Hg ratio, and when the removal ratio is 60, the precipitation efficiency reaches a value of 66.7%. Applying coagulation and flocculation procedures after the precipitation process increases the mercury removal efficiency. It is seen that with this application, mercury can be removed with an efficiency of 95.6% at the same reagent rate. With this application, the particle sizes of the precipitates are enlarged and their filtration properties are improved. It has also been determined that the precipitates formed are in the form of HgS, a stable mercury compound. These results indicate that mercury can be effectively removed in its steady state. It was found that the concentration of Au and Cu did not change significantly, while the concentration of Ag decreased during the precipitation processes.

Mercury Concentration in Saliva and the Impact of Chewing: An Inductively Coupled Plasma Mass Spectrometry Study.

Mercury, which is found in dental amalgams, is considered to be the most toxic non-radioactive element. However, the health policies of different countries have not reached a consensus on the use and safety of amalgam. This study aims to investigate the effect of amalgam restorations on mercury concentration in saliva, as well as the effect of restoration number, surface number, and chewing on this concentration. A total of 86 participants were included in this study (an equal number for the study and control groups). The number of amalgam restorations and their surfaces were recorded. While both unstimulated and stimulated saliva were collected from the study group, only unstimulated saliva was collected from the control group. The effect of chewing on mercury concentration was examined in the study group with unstimulated and stimulated saliva specimens using inductively coupled plasma mass spectrometry device. Mercury concentration in the unstimulated saliva was found to be higher in the study group compared to the control group (p= 0.000). As the number of amalgam restorations and the number of amalgam restoration surfaces increased, the mercury concentration in the saliva increased (p= 0.015 and p= 0.021, respectively). There was no statistically significant difference between mercury levels in the unstimulated saliva and the stimulated saliva (p=0.316). Chewing presented an insignificant difference in mercury concentration. Given this surprising result, the effect of chewing on mercury concentrations should be explored more extensively in future research.