Presence Of Amalgam Research Articles

Impact of dental restorations and removable prostheses on potentially malignant oral mucosal disorders in the general population

Statement of problemDental restorations and removable dental prostheses have been considered as risk factors for potentially malignant disorders of the oral mucosa. It remains unclear whether amalgam, composite resins, and prosthesis materials can induce potentially malignant disorders. PurposeThe purpose of this clinical study was to determine the relationship between the presence of amalgam and composite resin restorations, crowns and fixed partial dentures, and removable prostheses in potentially malignant disorders. Material and methodsThe data of 6041 participants in the population-based Studies of Health in Pomerania (SHIP) were accessed. Potentially malignant disorders had been clinically diagnosed by calibrated dentists and documented with photographs. Dental treatment was subdivided into restored and replaced teeth. Dental restorations were subclassified as buccal composite resin or amalgam restorations. Prosthetic treatment was subclassified into removable partial or complete prostheses and definitive restorations with crowns and fixed partial dentures. ResultsIn the maxilla, participants with removable prostheses had a higher incidence of potentially malignant disorders than participants not undergoing treatment with removable prostheses (OR 2.12; 95% CI: 1.08-4.18), but not in the mandible (OR 1.30; 95% CI: 0.67-2.53). The surfaces with composite resin restorations were associated with a slightly higher risk of mucosal lesions than those without the restorations (OR 1.04; 95% CI: 1.01-1.07). No significant association was found between amalgam restorations and mucosal lesions. ConclusionsParticipants with removable prostheses have a higher risk of potentially malignant disorders. Composite resin restorations are associated with a higher risk of mucosal lesions, whereas no significant association was found between amalgam restorations and mucosal lesions.

The Galvanic Effect of Titanium and Amalgam in the Oral Environment.

The effects of the presence of amalgam on titanium (Ti) dissolution in the oral environment under acidic, neutral, and basic conditions was studied. The presence of amalgam was found to suppress Ti release under acidic conditions due to the redeposition of TiOx/SnOx on the surface of the Ti. The redeposition of SnOx was due to the amalgam releasing its components (Hg, Cu, Sn, Ag) and the thermodynamic preference of Sn to oxidize, which was confirmed using mass measurements, ICP-MS analyses, and X-ray Photoelectron Spectroscopy (XPS). XPS depth profiling was performed to characterize the composition and oxidation states of the redeposited SnOx/TiOx film. Under basic conditions, the amalgam hindered Ti dissolution, but no redeposition of amalgam components was observed for the Ti.

Dose perturbation due to dental amalgam in the head and neck radiotherapy: A phantom study

Dental amalgam, causes perturbation in photon dose distribution of head and neck (H&N) radiotherapy. The aim of this study was to evaluate the effects of dental amalgam on dose distribution of H&N radiotherapy and accuracy of dose calculations algorithm of commercial treatment planning system (TPS). In this study, the measurements were performed using a constructed H&N anthropomorphic. The sample of healthy teeth and teeth filled by amalgam inserted in the desired segment of the phantom in turn. After scanning and organs segmentation of phantom, intensity-modulated radiation therapy (IMRT) plan including 7 fields in the absence (plan 1) and presence (plan 2) of dental amalgam were created separately. Phantom was irradiated using 6 MV linear accelerator (SIMENS-ARTISTE, 5918). Assessment of the effects of dental amalgam on dose distribution and the accuracy of dose calculation algorithm of TPS was done by measurement and comparing of organ's received dose using thermoluminescent dosimeter (TLDs), placed on a phantom and TPS calculations. The scattering and attenuation due to the presence of dental amalgam led to an increase in parotid glands received dose (up to 24.38%) and a decrease in mean dose (up to −6.25%) PTV70. Results of this study revealed that discrepancies between the collapsed cone convolution (CCC) algorithm calculations Prowess Panther TPS and TLD measurements were −19.77% to 27.49% in presence of amalgam and −1.09% to 5.03% in presence of healthy teeth in phantoms. Attenuation and scattering due to amalgam in IMRT of H&N cancer may lead to a significant dose perturbation which is not predictable by dose calculation of TPS.

Evaluation of mercury levels in hair of children resident in artisanal gold mining area in the city of Chapada de Natividade - Tocantins

ABSTRACT The objective of the work is to evaluate the mercury exposure of children living in an artisanal gold mining area and in a control area, without mining. A cross-sectional study was conducted with children living in the municipalities of Chapada de Natividade and Porto Nacional, in the State of Tocantins, where hair samples were collected for laboratorial analysis of mercury concentrations, comparing between municipalities, gender, monthly fish consumption, profession of parents and the presence of amalgam in dental restorations. The hair samples were analyzed by the methods of neutron activation analysis and also by means of the DMA (Direct Mercury Analyzer) equipment, in the last case being a partnership with CETESB. There was no evidence of mercury-related diseases in the studied children. The mean concentration of mercury in children in Chapada de Natividade was significantly higher than in Porto Nacional. Children exposed to artisanal gold mining areas have higher concentrations of mercury than children living in non- artisanal gold mining areas. There was no significant relationship between mercury concentrations and gender, monthly fish consumption, parental profession and amalgam presence in dental restorations. The results suggest that the children living in an area exposed to mining experience greater environmental exposure to mercury, regardless of their eating habits.

The impact of the use of amalgam in dental treatment on the prevalence of restless legs syndrome in older people.

The link between restless legs syndrome (RLS) and the number of amalgam fillings in older people was investigated. Restless legs syndrome decreases the quality of life and impairs normal functioning. Mercury (in amalgam) may be toxic to nerve cells and may account for the incidence of RLS. The relationship between RLS and the presence of amalgam in the teeth of 104 people aged 60-97 years old was determined. By using 4 questions, together with the diagnostic criteria from the internationally used questionnaire produced by the International Restless Legs Syndrome Study Group (IRLSSG), authors assessed the extent of the symptoms and occurrence of RLS. Careful medical history and medical examination were used for ascertaining each subject's type of restorative materials (i.e., amalgam or other metal) and the number of such fillings. Subjects who answered "yes" (indicating presence of RLS) to the 4 subsequent questions had a significantly higher number of amalgam dental fillings as compared to the subjects without RLS symptoms. Presence of other metal dental restorative materials and the number of amalgam dental fillings reported in the past had no significant influence on RLS symptomatology. Authors conclude that while examining the correlates of the appearance of restless legs syndrome the use of amalgam in the dentition should be taken into account. Med Pr. 2019;70(1):9-16.

THE INCREASED NUMBER OF EPITHELIAL CELLS DETACHED FROM ORAL MUCOSA BECAUSE OF AMALGAM FILLINGS

Amalgam is a filler material containing toxic mercury. One of the main risks comes from the mercury vapor released in the mouth. The presence of amalgams in the oral cavity changes the metabolism of epithelial cells in the oral mucosa. Exfoliative cytology is a fast and easy method because the examination is only performed on the surface of the oral mucosa, and epithelial cells can be released without anesthesia. The research method was an analytical descriptive with a cross-sectional design. Epithelial cells from oral mucosa were collected from 32 samples using the cytobrush method. The epithelial cells were collected on the closest buccal mucosa of the amalgam restoration. The number of epithelial cells in the oral mucosa was seen through micrographs from a microscope with 100x magnification. The data were analyzed using the Mann Whitney U test to determine the number of epithelial cells released. The Mann Whitney U test results showed that there was a significant difference in the number of oral mucosal epithelial cells obtained ​​between subjects with amalgam and subjects without amalgam with p<0.05. In addition, there was a difference in the features of oral mucosal epithelial cells between subjects with amalgam and subjects without amalgam. In conclusion, the number of epithelial cells obtained from amalgam users was higher than the subjects without restorations. The forms of epithelial cells which experience desquamation in the subjects with amalgam were more irregular than those of subjects without restorations.

Evaluation of the effect of tooth and dental restoration material on electron dose distribution and production of photon contamination in electron beam radiotherapy.

The aim of this study is to evaluate the effect of tooth and dental restoration materials on electron dose distribution and photon contamination production in electron beams of a medical linac. This evaluation was performed on 8, 12 and 14 MeV electron beams of a Siemens Primus linac. MCNPX Monte Carlo code was utilized and a 10 × 10 cm(2) applicator was simulated in the cases of tooth and combinations of tooth and Ceramco C3 ceramic veneer, tooth and Eclipse alloy and tooth and amalgam restoration materials in a soft tissue phantom. The relative electron and photon contamination doses were calculated for these materials. The presence of tooth and dental restoration material changed the electron dose distribution and photon contamination in phantom, depending on the type of the restoration material and electron beam's energy. The maximum relative electron dose was 1.07 in the presence of tooth including amalgam for 14 MeV electron beam. When 100.00 cGy was prescribed for the reference point, the maximum absolute electron dose was 105.10 cGy in the presence of amalgam for 12 MeV electron beam and the maximum absolute photon contamination dose was 376.67 μGy for tooth in 14 MeV electron beam. The change in electron dose distribution should be considered in treatment planning, when teeth are irradiated in electron beam radiotherapy. If treatment planning can be performed in such a way that the teeth are excluded from primary irradiation, the potential errors in dose delivery to the tumour and normal tissues can be avoided.

Scalp hair and urine mercury content of children in the Northeast United States: The New England Children's Amalgam Trial

Children may be at particular risk from toxic effects of mercury (Hg). Previous studies of hair (organic) and urine (inorganic) Hg levels in US children were unable to assess Hg levels while accounting for exposure to amalgam dental restorations. This analysis describes, over a 5-year period, levels and correlates/predictors of scalp hair (H-Hg) and urinary (U-Hg) mercury in 534 New England Children's Amalgam Trial (NECAT) participants, aged 6–10 years and without exposure to dental amalgam at baseline. Results: Mean H-Hg levels were between 0.3 and 0.4 μg/g over 5 years. 17–29% of children had H-Hg levels ⩾0.5 μg/g, and 5.0 to 8.5% of children had levels ⩾1 μg/g, in any given study year. In adjusted models, fish consumption frequency was the most robust predictor of high H-Hg. U-Hg mean levels were between 0.7 and 0.9 μg/g creatinine over two years. The percentage of those with U-Hg ⩾2.3 μg/g creatinine ranged from 4% to 6%. Number of amalgam restorations had a significant dose-response relationship with U-Hg level. Daily gum chewing in the presence of amalgam was associated with high U-Hg.

The effect of amalgam exposure on mercury- and antibiotic-resistant bacteria

Antibiotic resistance genes can be found on the same mobile genetic elements as genes coding for resistance to metals such as mercury (Hg). Amalgam restorations contain ca. 50% Hg and, therefore, it could be expected that exposure to such dental restorative materials may promote Hg resistance and thereby antibiotic resistance. An in vitro biofilm model was used to grow microcosm dental plaques on enamel or amalgam substrata. The number and proportion of Hg-resistant organisms over time were determined by viable counts. Microcosm dental plaques grown in the presence of amalgam had a higher number and proportion of Hg-resistant bacteria than those grown on enamel. The levels of these Hg-resistant bacteria remained elevated for a period of 48 h, however after 72 h the proportions returned to baseline levels. Of the 42 Hg-resistant bacteria isolated, 98% were streptococci, with Streptococcus mitis predominating. A high proportion of the Hg-resistant isolates (71%) were also resistant to a range of antibiotics, with resistance to tetracycline being encountered most frequently. The results of this in vitro study indicate that placement of amalgam restorations may play a role in promoting the levels of Hg- and antibiotic-resistant bacteria present in the oral cavity.

TU‐FF‐A4‐05: Feasibility of Tracking Wireless AC Electromagnetic Transponders in Head and Neck Cancer Environment

Purpose: Precision setup is essential for head and neck IMRT due to the steep dose gradients used. A new device called the Calypso® 4D Localization System (Seattle, WA) has been developed which is capable of performing objective, real‐time target tracking during radiation. This system is based on non‐ionizing AC electromagnetics that utilizes small wireless Beacon® transponders, and could potentially be used to localize transponders embedded in a mouthpiece as a method to track skull movement during head and neck irradiation. Because AC electromagnetics can be influenced by nearby conductive metals, the effect of dental restorations, such as amalgam, on transponder localization accuracy was studied. Method and Materials: A dental prosthesis was casted from a volunteer. 16 of 28 prosthetic teeth were filled with standard dental amalgam. Three transponders set in a fixture were placed under the detection array and baseline measurements of each transponder's x, y and z coordinates away from the array were obtained. Next the prosthesis was placed immediately posterior to the transponders, simulating a worst‐case scenario of nearby amalgam. Each transponder's coordinates from the array were re‐measured. The transponders coordinates in the presence of the prosthesis were compared to the baseline measurement without the prosthesis. The experiment was repeated with transponders up to 20 cm away from the detection array. Results: Results showed that the presence of amalgams had no measurable effect on the system's capability to localize multiple transponders at distances up to 20 cm from the array. Conclusion: This investigation demonstrates the potential of wireless AC electromagnetic technology embedded in a mouthpiece to enable accurate and continuous tracking of the skull during head and neck IMRT. Conflict of Interest: Work supported by Calypso Medical Technologies; Authors Mate, Zeller, Eidens and Vertatschitsch have a financial interest in Calypso Medical.

An in vitro study into the corrosion of intra-oral magnets in the presence of dental amalgam.

The aim of this investigation was to study the corrosion behaviour and products of uncoated neodymium-iron-boron magnets in the presence of dental amalgam. Microcosm plaques were grown on discs of neodymium-iron-boron magnets or amalgam in a constant depth film fermentor. The biofilms were supplied with artificial saliva and growth was determined by viable counting. The results showed that the neodymium-iron-boron magnets corroded with an average daily weight loss of 0.115 +/- 0.032 per cent. However, when the magnets were in close proximity to the amalgam the amount of corrosion was reduced to a daily loss of 0.066 +/- 0.023 per cent. The highest loss of constituent elements from the corrosion products of the magnets was observed for iron. The composition of the microcosm plaques altered markedly between the two materials with less streptococci and more Veillonella spp. present in the biofilms grown on magnets in the presence of amalgam. The corrosion of neodymium-iron-boron magnets is limited and in the presence of amalgam is reduced further. This suggests that amalgam present in the mouth will not cause an increased clinical risk in terms of biocompatibility with neodymium-iron-boron magnets.

Oral lichen planus and dental materials: a case-control study.

The purpose of this study was to examine the association of dental materials with oral lichen planus (OLP) and, particularly, the effects of amalgam, amalgam corrosion status, gold and dissimilar metals in continuous contact. A case-control study was performed with 43 OLP cases from the Oral Medicine Clinic at the School of Dentistry, University of Washington and 78 controls from a general dental care-screening clinic, also at the School of Dentistry, University of Washington. Health histories and oral examinations were obtained. Current metal or metal-based restorations were charted, along with corrosion status of amalgams and the presence of dissimilar metals in continuous contact. Adjusted odds ratios (ORs) and 95% confidence intervals for the following potential risk factors were found to be: (1) number of teeth with amalgam, OR = 1.02 (0.92, 1.13); (2) total surfaces of amalgam, OR = 0.96 (0.92, 1.0); (3) number of teeth with gold, OR = 1.12 (0.95, 1.31); (4) mean amalgam corrosion score, OR = 5.74 (2.34, 14.1); (5) presence of dissimilar metals in contact (per quadrant), OR = 1.25 (0.81, 1.92). These findings suggest that although the presence of amalgam or gold themselves is not associated with increased risk of OLP, corrosion of amalgams and the presence of a 'galvanic effect' from dissimilar dental materials in continuous contact (bimetallism) are associated with an increased risk of OLP.