Types Of Amalgam Research Articles

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.

Silver, cobalt and nickel mineralogy and geochemistry of shale ore in the sediment-hosted stratiform Nowa Sól copper–silver deposit, SW Poland

The Nowa Sól deposit is a part of the newly discovered Northern Copper Belt and is situated some 30 km NW of the Lubin–Sieroszowice mining district (the so-called New Copper District) in SW Poland. The ore horizon spans across the upper part of the Lower Permian (Rotliegend) terrestrial redbeds and the lower part of the Upper Permian (Zechstein) marine rocks. It comprises three lithotypes: sandstone, shale and carbonate. The high-grade shale ore has polymetallic characteristics and is a crucial host for by-product metals such as Ag, Co and Ni (studied in this paper), but also Mo, V and Re. The results of bulk-rock and electron microprobe as well as mineralogical (optical and scanning electron microscope) data of the mineralized, organic-rich shale ore from the Nowa Sól deposit are presented. This thin stratigraphic horizon, ranging from 0.06 to 0.59 m, shows notable concentrations of critical metals, including on average 15.9 wt% Cu, 715 grams per tonne (g t -1 ) Ag, 318 g t -1 Co and 345 g t -1 Ni. It constitutes less than 10% of the total ore mass, but accounts for 36% of the Ag, 40% of the Ni and 42% of the Co found within the deposit. The ore sulfides in the mineralized shale in the Nowa Sól deposit include chalcocite, djurleite and bornite, accompanied by digenite, covellite, tennantite, galena, sphalerite and pyrite. The Ag content within the Cu sulfides exhibits a linear decrease: chalcocite &gt; djurleite &gt; bornite. Three primary Ag minerals are identified within the shale ore, namely native Ag, Ag amalgam and stromeyerite. Two types of Ag amalgam are observed: Hg-rich and Hg-poor. Cobaltite and gersdorffite represent the primary Co and Ni minerals, occurring as micrometre-sized inclusions within chalcocite and djurleite. Textural observations suggest that the Ag, Co and Ni mineralization postdates the major phase of Cu sulfide precipitation. It is shown that in the Nowa Sól deposit, the Kupferschiefer horizon has acted as a geochemical barrier for the above-mentioned metals during protracted time, from early syndepositional to late epigenetic stage of basin evolution. Supplementary material: The supplementary material contains the results of the electron microprobe analyses and the specific experimental conditions employed for these analyses – available at https://doi.org/10.6084/m9.figshare.c.6873631

From a dialogue of cultures to a dialogue of ideas: The Swedish theosophist Emanuel Swedenborg in the perception of the German psychiatrist Karl Leonhard in the context of the current discussion

This article completes a series of works on the reception of Scandinavian and Dutch cultural heritage in the works of the outstanding German psychiatrist and psychologist Karl Leonhard (1904–1988). His assessments already deserve attention because the portraits of remarkable artists, writers, and thinkers presented in his works, thanks to the research and undoubted literary talent of their author, on the one hand, go beyond the usual pathographies in terms of depth of analysis and mastery of presentation. On the other hand, the portraits serve as artifacts of an era in the history of medicine, when on the foundation of a cultural dialogue between Russia and Germany a unique dialogue of the German and Russian psychiatric thought developed — something that the historical vicissitudes of the twentieth century could not prevent. The authors of the article make an attempt to bring together the approaches available to the history of culture to study the perception of the personality and work of Emanuel Swedenborg (1688–1772) as reflected in Leonhard’s last book. Leonhard’s assessments not only capture a certain period in the reception history of the Swedish thinker and naturalist in German culture — they are a monument to the peculiar naturalistic culture of German nosological psychiatry, inscribed in the history of medical thought. Clinical experience leads the German psychiatrist to conclude that Swedenborg’s diagnosis of schizophrenia in its traditional Kraepelinian sense, which the Russian school of psychiatry is inclined to follow, is wrong, but the German psychiatrist himself comes to the conclusion that Swedenborg has an amalgam type of psychosis — phonemic confabulation paraphrenia. Following Leonhard, the authors of the article examine Swedenborg’s works, the testimonies of his contemporaries about him and his family as well as reproduce the picture of symptoms of mental illness taking into account the latest historical, cultural and medical-psychological works about the Swedish mystic. In their critical analysis, the authors emphasize the relevance of the classification of Leonhard’s endogenous psychoses, drawing the reader’s attention to the evidence about Swedenborg’s emotional- volitional and cognitive sphere within the historical and cultural context of 18th century Sweden. In conclusion, the authors announce the publication of the full text of Leonhard’s essay translated into Russian with historical, cultural and medical-psychological commentary.

Measuring mercury in urine among students &amp; professors at the faculty of dentistry exposed to mercury vapor by cold vapor atomic absorption technique

Introduction: Dentists are exposed to mercury vapor due to the occupational exposure to amalgam, which can endanger their health. The aim of this study was to determine the effect of mercury vapor on urinary mercury concentration of dental students and the restorative specialists in one of the dental schools of Iran. Methods: The study population consisted40 dental students and 10 restoration specialists. Sample urine at the end of work time was collected, and the concentration of mercury in urine was measured by cold vapor atomic absorption spectrophotometry. A questionnaire was completed to determine the effects of some personal and environmental factors on the amount of urinary mercury. Data were analyzed using SPSS-22 software. Results: The mean concentration of urinary mercury in dental students was 15.18±4.34μg/L and the restoration specialists were 4.11±1.05μg/l. In addition, there was a significant difference between the concentrations of urinary mercury in the two groups (P &lt;0.001). At specialist professors there was a negative correlation between urinary mercury and working hours per day (r=-0.78, p=0.007). Also, in this study, there was a significant relationship between urine mercury and sex, age, type of amalgam consumed, consumption of smoking and the number of amalgam restorations. Conclusion: The level of urine mercury in all samples was lower the recommended amount of ACGIH. The study is recommended mercury level monitoring for regularly evaluation of the workplace.

A weighted inequality for potential type operators

AbstractWe establish a weighted inequality for fractional maximal and convolution type operators, between weak Lebesgue spaces and Wiener amalgam type spaces on {\mathbb{R}} endowed with a measure which needs not to be doubling.

An evaluation of the Effect of Surface Treatment On Amalgam Repair

The purpose of this in vitro study was to evaluate the effect of different surface treatments on shear bond strength of repaired amalgam using two types of amalgam. 120 acrylic blocks (2.7cm diameter by 2.0cm high) were constructed from cold cure resin, each one contained cylindrical hole (7mm diameter by 2mm high) on its circular face that filled with amalgam. The samples were divided into immediate repair group and delayed repair group, which was stored and incubated at 37C0 for one month. After aging the amalgam surface of delayed repair was finished with carbide bur and polished with abrasive rubber cup then divided into three groups according to the surface treatment that include group with out surface treatment, group roughened with diamond bur and the last group was abraded with aluminum oxide (50m) particles size, both immediate and delayed repair were further subdivided according to the type of amalgam used into three subgroups. The repair procedure was done by using a Teflon split mold which containing an opening (3mm diameter by 5mm high) then all the samples were storage and incubated at 37C0 for one week prior to testing.Testing was done by applying shear force at the interface between the initial and repair amalgam with special designed chisel shape rod by using Zwick testing machine at across head speed of 5mm/min.Analysis of the results showed that the shear bond strength in immediate repair were significant higher than of delayed repair and the group roughened with diamond bur is higher than group treated with aluminum oxide and untreated group.The shear bond strength of delayed repair of amalgam is less than that of immediate repair, the surface produced by roughening the samples with a diamond bur will give best strength than the surface treated by aluminum oxide and untreated surface (smooth surface) and the same types of amalgam restorations used in amalgam repair gave better result than different type of amalgam.

고출력 무전극램프의 가스압 및 아말감종류에 따른 특성분석 및 최적화에 관한 연구

고출력 무전극램프의 가스압 및 아말감종류에 따른 특성분석 및 최적화에 관한 연구

Increased mercury emissions from modern dental amalgams

All types of dental amalgams contain mercury, which partly is emitted as mercury vapor. All types of dental amalgams corrode after being placed in the oral cavity. Modern high copper amalgams exhibit two new traits of increased instability. Firstly, when subjected to wear/polishing, droplets rich in mercury are formed on the surface, showing that mercury is not being strongly bonded to the base or alloy metals. Secondly, high copper amalgams emit substantially larger amounts of mercury vapor than the low copper amalgams used before the 1970s. High copper amalgams has been developed with focus on mechanical strength and corrosion resistance, but has been sub-optimized in other aspects, resulting in increased instability and higher emission of mercury vapor. This has not been presented to policy makers and scientists. Both low and high copper amalgams undergo a transformation process for several years after placement, resulting in a substantial reduction in mercury content, but there exist no limit for maximum allowed emission of mercury from dental amalgams. These modern high copper amalgams are nowadays totally dominating the European, US and other markets, resulting in significant emissions of mercury, not considered when judging their suitability for dental restoration.

Pin Retained Restoration: A Case Report

Pin retained amalgam restoration are a type of amalgam or resin restoration of a complex nature requiring the placement of one or more pins in the dentin to provide adequate retention and resistance forms. The pin-retained amalgam is a valuable treatment aid in the restoration of teeth with extensive carious lesions or fractures. The pins help in binding the amalgam/composite to the tooth structure. The case report given in this article presents the recovery of fractured anterior teeth with dentinal pins and composite restoration.

Graphite oral tattoo: case report

Pigmented oral lesions compose a large number of pathological entities, including exogenous pigmentat oral tattoos, such as amalgam and graphite tattoos. We report a rare case of a graphite tattoo on the palate of a 62-year-old patient with a history of pencil injury, compare it with amalgam tattoos, and determine the prevalence of oral tattoos in our Oral Pathology Service. We also compare the clinical and histological findings of grafite and amalgam tattoos. Oral tattoos affect women more frequently in the region of the alveolar ridge. Graphite tattoos occur in younger patients when compared with the amalgam type. Histologically, amalgam lesions represent impregnation of the reticular fibers of vessels and nerves with silver, whereas in cases of graphite tattoos, this impregnation is not observed, but it is common to observe a granulomatous inflammatory response, less evident in cases of amalgam tattoos. Both types of lesions require no treatment, but in some cases a biopsy may be done to rule out melanocytic lesions.

Is high-viscosity glass-ionomer-cement a successor to amalgam for treating primary molars?

ObjectivesTo assess and compare the cumulative survival rate of amalgam and atraumatic restorative treatment (ART) restorations in primary molars over 3 years. Methods280 children aged 6–7 years old were enrolled in a cluster randomized controlled clinical trial using a parallel group design covering two treatment groups: conventional restorative treatment with amalgam (CRT) and atraumatic restorative treatment (ART) using a high-viscosity glass-ionomer (HVGIC) Ketac Molar Easymix. Three pedodontists placed 750 restorations (364 amalgam and 386 ART in 126 and 154 children, respectively) which were evaluated at 0.5, 1, 2 and 3 years. The proportional hazard rate regression model with frailty correction, ANOVA and Wald tests, and the Jackknife procedure were applied in analysing the data. ResultsThe cumulative survival rates over 3 years for all, single- and multiple-surface CRT/amalgam restorations (72.6%, 93.4%, 64.7%, respectively) were no different from those of comparable ART/HVGIC restorations (66.8%; 90.1% and 56.4%, respectively) (p=0.10). Single-surface restorations had higher survival rates than multiple-surface restorations for the both treatment procedures (p<0.0001). A higher proportion of restorations failed because of mechanical reasons (94.8%) than of secondary caries (5.2%). No difference in reasons for restoration failures between all types of amalgam and ART/HVGIC restorations were observed (p=0.24). SignificanceThe high-viscosity glass-ionomer used in this study in conjunction with the ART is a viable option for restoring carious dentin lesions in single surfaces in vital primary molars.

Fourier transforms on an amalgam type space

We introduce an amalgam type space, a subspace of \(L^1(\mathbf R_+)\). Integrability results for the Fourier transform of a function with the derivative from such an amalgam space are proved. As an application, we obtain conditions for the integrability of trigonometric series.

The effect of 3 T MRI on microleakage of amalgam restorations

To evaluate the effects of 3 T magnetic field on microleakage of amalgam restorations containing three different types of silver (Ag). 60 extracted teeth were restored with three different types of amalgam filling materials. Restored teeth were sectioned mesiodistally and divided into experimental and control groups. Experimental groups were exposed to a magnetic field of 3 T for 20 min. All samples were plunged into 2% basic fuchsin solution and examined under a digital microscope by three different observers with regard to microleakage. Statistical analysis showed significant differences in microleakage between the groups exposed to MRI and controls, whereas differences in microleakage between amalgam types were insignificant. The primary risk of MRI systems arises from the effects of its strong magnetic field on objects containing ferromagnetic materials. An MRI of 1.5 T is known to be safe for amalgam restorations. However, our research indicates that MRI is not completely devoid of any effects on amalgam restorations.

Effect of 10% Carbamide Proxide on Mercury Release from Two Types of Dental Amalgam

Statement of Problem: The chemical reactions occur at the amalgam surface when exposed to bleaching agents. Mercury ion is released from dental amalgam when bleached. Purpose: The aim of this in vitro study was to investigate the effect of carbamide peroxide (CP) on the release of mercury ion from two types of spherical dental amalgam. Materials and Method: Two commercial brands of dental amalgam, Cinalux and GS-80, were selected. 18 amalgam discs of any brand were prepared in silicon moulds according to the manufacturer's instructions. After 60 minutes, the discs were removed and individually immersed in artificial saliva (AS) for 24 h at 37 0C . Then, the discs of any amalgam were divided into two equal test group (A) and control group (B). Each specimen in the test group was treated in eighthour cycles with 10% CP. The specimens of the control group was treated in similar cycles with AS. All of the solutions were taken for Hg ion release determination, using cold-vapor atomic absorption mercury analyzer system. The data were analyzed using General Linear Model followed by Repeated Measures ANOVA. Results: The results indicated that the bleaching agent significantly caused more mercury ion to be released into the solutions ( p <0.05) but artificial saliva did not show this effect. The release rate of mercury from the Cinalux during the two weeks of treatment period with 10% CP showed an increase from 11.63 µg/lit in the first day to 228.85 µ g/lit in the last day. The release rate from GS-80 showed a decrease from 130.96 µg/lit in the first day to 80.68 µ g/lit in the last day. Conclusion: Treatment with %10 carbamide peroxide increased mercury release from dental amalgam in comparison with the artificial saliva. The release of Hg from 2 brands of dental amalgam was in a safe range.

The Effect of a 16% Carbamide Peroxide Gel on Mercury and Silver Ion Release from Admixed and Spherical Dental Amalgams

The aim of this study was to investigate the effect of 16 percent carbamide peroxide gel on mercury and silver ions released from admixed and spherical dental amalgams. A total of 96 amalgam discs were prepared from two different types and brands of dental amalgam (admixed and spherical). The samples were stored at room temperature in glass tubes containing distilled water for 24 hours. The specimens were then polished and again immersed in distilled water at room temperature and stored for one month. Samples of both types of dental amalgam were treated with carbamide peroxide 16 percent gel (Nite White, Discus Dental, Inc., Culver City, CA, USA) for 14 and 28 hours (experimental group) and compared to samples not exposed to the bleaching agent but stored continuously in distilled water. Mercury and silver levels of each solution were measured using the VAV-440 analyzer system. Mercury and silver ions released from the experimental group were significantly greater than from the control group (p<0.001). There was no significant difference between the mean levels of mercury and silver ions in the two kinds of amalgams after treatment with 16 percent carbamide peroxide (p=0.119 for mercury and p=0.199 for silver). Increasing the storage time in the carbamide peroxide gel from 14 to 28 hours did not result in significant changes in the amount of ions released (p=0.329 for mercury and p=0.082 for silver). Also, the interaction effect between amalgam particles' shape (admixed and spherical) versus storage time (14 versus 28 hours) was not statistically significant (p=0.901 for mercury and p=0.951 for silver). Treatment with 16 percent carbamide peroxide gel increased mercury and silver ions released from admixed and spherical amalgams, compared to samples in the control group, but the difference between the two amalgams was not statistically significant. The amount of mercury and silver ions released from high-copper dental amalgams during bleaching with 16 percent carbamide peroxide is in the safe range of mercury intake for patients.

Costing Dental Restorations in Public Sector Dental Clinics

The objective of this study is to share cost analysis methodology and to obtain cost estimates for posterior restorations in public sector dental clinics. Two urban and 2 rural dental clinics in Selangor state were selected. Only cases of 1 posterior restoration per visit by dental officers were included over 6 months. One capsulated amalgam type, 1 capsulated tooth-colored, and 1 non-capsulated tooth-colored material were selected. A clinical pathway form was formulated to collect data per patient. Annual capital and recurrent expenditures were collected per clinic. The mean cost of an amalgam restoration was RM 30.96 (sdRM 7.86); and tooth-colored restorations ranged from RM 33.00 (sdRM 8.43) to RM 41.10 (sdRM 10.61). Wherein 1 USD = RM 2.8. Restoration costs were 35% to 55% higher in clinics in rural areas than in urban areas. The findings demonstrate economy of scale for clinic operation and restoration costs with higher patient load. Costs per restoration were higher in rural than in urban dental clinics. More studies are recommended to address the dearth of dental costs data in Malaysia.

Comparison of chlorine and chloramine in the release of mercury from dental amalgam

The purpose of this project was to compare the ability of chlorine (HOCl/OCl −) and monochloramine (NH 2Cl) to mobilize mercury from dental amalgam. Two types of amalgam were used in this investigation: laboratory-prepared amalgam and samples obtained from dental-unit wastewater. For disinfectant exposure simulations, 0.5 g of either the laboratory-generated or clinically obtained amalgam waste was added to 250 mL amber bottles. The amalgam samples were agitated by end-over-end rotation at 30 rpm in the presence of 1 mg/L chlorine, 10 mg/L chlorine, 1 mg/L monochloramine, 10 mg/L monochloramine, or deionized water for intervals of 0 h, 2 h, 4 h, 8 h, and 24 h for the clinically obtained amalgam waste samples and 4 h and 24 h for the laboratory-prepared samples. Chlorine and monochloramine concentrations were measured with a spectrophotometer. Samples were filtered through a 0.45 µm membrane filter and analyzed for mercury with USEPA standard method 245.7. When the two sample types were combined, the mean mercury level in the 1 mg/L chlorine group was 0.020 mg/L ( n = 25, SD = 0.008). The 10 mg/L chlorine group had a mean mercury concentration of 0.59 mg/L ( n = 25, SD = 1.06). The 1 mg/L chloramine group had a mean mercury level of 0.023 mg/L ( n = 25, SD = 0.010). The 10 mg/L chloramine group had a mean mercury level of 0.024 mg/L ( n = 25, SD = 0.011). Independent samples t-tests showed that there was a significant difference between the natural log mercury measurements of 10 mg/L chlorine compared to those of 1 mg/L and 10 mg/L chloramine. Changing from chlorine to chloramine disinfection at water treatment plants would not be expected to produce substantial increases in dissolved mercury levels in dental-unit wastewater.

Features of the absorption spectra of thin films of M 2Ag1 − x CuxI3 solid solutions (M = Rb, Cs)

The absorption spectra of thin films of (MI)1 − y (Ag1 − x CuxI)y solid solutions (M = Rb, Cs) with the initial molar concentration y = 0.33 have been investigated. It is established that, at low concentrations x, a local exciton band due to Cu+ ions is split off from the main long-wavelength exciton bands. In Rb2Ag1 − x CuxI3 solutions, the concentration shift of exciton bands indicates the formation of a persistent-type exciton spectrum. However, in Rb2Ag1 − x CuxI3 with x ≥ 0.5 and in Cs2Ag1 − x CuxI3 with x > 0.2, exciton spectra of amalgamation type are observed, which are related to the formation of more stable M 3Ag2 − 2x Cu2x I5 solid solutions. The formation of these solutions leads to broadening of the exciton bands and to the concentration transition from persistent-to amalgamation-type exciton spectra.

Structural and optical properties of polycrystalline CdSe xTe 1− x (0 ≤ x ≤ 0.4) thin films

CdSe x Te 1− x (0 ≤ x ≤ 0.4) ternary thin films have been deposited on quartz substrates at room temperature by a single source thermal evaporation. X-ray diffraction patterns and transmission electron microscope micrographs of these films showed that the films were of polycrystalline texture over the whole range studied and exhibit predominant cubic (zinc blende) structure with strong preferential orientation of the crystallites along (1 1 1) direction. Linear variation of the lattice constant with mole fraction x is observed obeying Vegard's law. The dependence of the optical constants, the refractive index n and extinction coefficient k, of the films on the mole fraction x was studied in the spectral range of 400–2500 nm. The normal dispersion of the refractive index of the films could be described using the Wemple–DiDomenco single-oscillator model. CdSe x Te 1− x thin films of different composition have two direct and indirect transitions corresponding to energy gaps E g d and E g ind . The variation in either E g d or E g ind with x indicates that this system belongs to the amalgamation type. The variation follows a subquadratic dependence and the bowing parameters were found to be 0.36 and 0.48 eV for the direct, and indirect energy gaps, respectively. Direct linear variation of the ratio N/ m * with x is observed.

Spectroscopic properties of the mixed J-aggregate of unsymmetric merocyanine dyes in wide temperature range

The monolayer assemblies incorporating two kinds of unsymmetric merocyanine dye aggregates (MC(X)/MC(Y), X = O, S, Se) have been fabricated by the Langmuir–Blodgett technique. The absorption spectra of the Langmuir–Blodgett films were measured in wide temperature range of T = 6.0–293 K. The absorption spectra of the MC(O)/MC(S) and the MC(O)/MC(Se) assemblies bear two absorption bands which are assigned to the MC(O) aggregate and the MC(S) J-aggregate or the MC(Se) J-aggregate, respectively. In contrast, the absorption spectrum of the MC(S)/MC(Se) assembly shows a single absorption band of the mixed J-aggregate. From detailed considerations of the low-energy tail of absorption spectra based on the Urbach–Martienssen rule, together with other spectroscopic properties, it is concluded that the MC(O)/MC(S) or the MC(O)/MC(Se) assembly forms a mosaic aggregate. The MC(S)/MC(Se) assembly can form high-quality homogeneous aggregate of amalgamation type.