(French amalgame, - a device for softening blows) - a metal system, one of the components of which is. One of the oldest materials (known for more than 2000 years), the widespread use of which began in the 19th century. There are simple amalgams, containing, in addition to mercury, one metal, and mixed (complex), to-rye contain, in addition to mercury, two or more metals.

Amalgam is obtained by electrochemical and chemical methods, as well as by the direct interaction of metals and mercury. At room temperature, amalgam is liquid, semi-liquid (suspension) and solid. Liquid include amalgam of metals that are highly soluble in mercury (silver, gold, tin, zinc, cadmium, thallium, lead, magnesium and indium), if their concentration does not exceed the solubility limit; to semi-liquid - amalgamation of metals poorly soluble in mercury (aluminum, cobalt, iron, titanium, nickel, etc.); to solid - A. metals, highly soluble in mercury, if their concentration exceeds the solubility limit. A. differ in a liquid state in a wide t-r range, inertness with respect to some aggressive media, good thermophysical properties, high density.

Some intermetallics with metals have semiconductor and superconducting properties. Amalgamated surfaces protect certain metal products, e.g. zinc, from the action of sulfuric acid. Liquid amalgams are widely used, on the basis of which amalgam metallurgy of indium, cadmium, thallium, lead and gallium is created.

Amalgam of gold is used for gilding items made of silver, copper, brass and bronze. The possibility of using aluminum as heat carriers in ferrous metallurgy is being studied. Solid diamonds are used in dentistry (alloy 59-66% Hg, 32-37% Cu, 2-4% Zn), as solder (alloy 4% Hg, 3% Sn, 93% Pb), in the production of mirrors ( alloy 30% Hg, 70% Sn). Mercury toxicity somewhat limits the use of amalgam.

Yet onea remarkable property of mercury: the ability to dissolve others, forming solid or liquid solutions - amalgams. Some of them, such as silver amalgamsAnd cadmium, are chemically inert and hard at human body temperature, but soften easily when heated. Of them making dental fillings.Thallium amalgam, which hardens only at -60°C, is used in special designs of low-temperature thermometers.

Antique mirrors were covered not with a thin layer of silver, as is done now, but with an amalgam, which included 70% tin and 30% mercury. In the past, amalgamation was the most important technological process when extracting gold from ores. In the 20th century, it could not stand the competition and gave way to a more advanced process - cyanidation. However, the old process is still used today, mainly in the extraction of gold, finely interspersed in the ore. Some, in particular, are practically not amenable to amalgamation. This makes it possible to transport liquid metal in plain steel containers. (Especially clean is transported in containers made of glass, ceramics or plastic.)

In addition to iron and its analogues, they are not amalgamated, and there are almost all used for alloying steel. This means that alloyed steel is not terrible. But, for example, it is very easy to amalgamate. Sodium amalgam is easily decomposed by water. These two circumstances have played and continue to play a very important role in the chlorine industry. In the production of chlorine and caustic soda by the electrolysis of common salt, cathodes from metallic mercury are used. To get a ton of caustic soda, you need from 125 to400 g item no. 80. Today, the chlorine industry is one of the largest consumers of metallic mercury.

Lit .: Gavze MN Interaction of mercury with metals and alloys.

Article on Amalgam

The beautiful word "amalgam" is widely known, but not everyone can say exactly what it means. Moreover, this concept has a lot of meanings.

Translated from Latin, amalgama is simply "alloy", but in Russian this word is more specific and refers to an alloy of one or more metals with mercury. At room temperature, mercury is a liquid and is capable of reacting with silver, tin, etc. to form solid materials as a result. Ancient alchemists believed that mercury was endowed with a special mystical power.

Synonyms of the word "amalgam" in the figurative meaning of this word - "mixture" - connection, conglomerate, collection, composition. Hence the multiple associations with old books, and the popularity of the term "amalgam" in the names of some modern companies, in particular, specializing in the translation of foreign texts and films.

Perhaps the most famous meaning of the word "amalgam" is associated with the technology of making mirrors that was widely used in its time.

antique mirrors

For the first time, mirror manufacturing technology using amalgam, an alloy of mercury and tin, was used in the 16th century. However, over time, it was abandoned, because. such mirrors gave a pale reflection, moreover, in their manufacture, workers sometimes received severe mercury vapor poisoning. In the 19th century, instead of mercury, glass began to be coated with a thin layer of silver.

The reflection in the silver mirrors was bright and clear. In modern technologies, aluminum is used in the manufacture of mirrors, sometimes silver, tin, copper, as well as chemical activators. From above, the reflective layer applied to the glass is covered with protective varnishes or paints.

Dental fillings

Until recently, silver amalgam was widely used in dentistry as one of the most durable filling materials. Now it is being successfully replaced with composite resins and all-ceramics, however, for the restoration of large areas of teeth, silver amalgam fillings with the addition of copper are still used today.

The amount of mercury coming from the fillings into the patient's body does not exceed the permissible values. But the medical staff permanent job with amalgams, safety rules must be carefully observed.

In addition, to prevent mercury vapor from being absorbed into the walls, the inside of the dental office should be painted with nitro enamel or oil paint, and wooden furniture should not be present in it.

When removing amalgam fillings, the load on the patient's body increases, so the working field should be maximally isolated from the oral cavity by applying sealed materials. It is very important to prevent the discharge of mercury compounds into the sewer.

Getting into environment, in particular - in the water course, organic mercury compounds can be converted into inorganic forms and absorbed by living organisms. Such seafood, when eaten, can cause severe poisoning.

Other applications

Compounds with mercury are also used in metallurgy, in gilding and silvering. jewelry, are used in various devices, take part in cold welding in microelectronics.

And the very concept of "amalgam", as noted above, is interpreted in a much broader sense - it is used in higher mathematics, literature, in naming to refer to various forms of compounds, etc.

Definition

Properties

Receipt

Application

Amalgam in dentistry

Functions of the amalgam alloy components

Classification

Properties

Receipt

Corrosion

Amalgam representatives

Work space

Definition

Amalgams- alloys of metals with mercury.

Amalgams- intermediate products in the extraction of yellow metal and other noble metals from ores and concentrates.

Amalgam - liquid or solid mercury alloys with other metals. Also, the amalgam can be a solution of ionic complexes behaving similarly to metals (for example, ammonium).

Amalgam is the professional name for one of the filling materials, the properties of which use the ability of mercury to dissolve certain metals.

Amalgam is an alloy of one or more metals with mercury.

Amalgams - the so-called compounds (alloys) of mercury with other metals; hence - amalgamate, combine with mercury, cover (from the surface) metal objects with mercury.

Amalgam is a mixture of mercury and other metals. At room temperature, mercury is a liquid and easily reacts with metals such as , and , during which solid materials are formed.

Properties

Depending on the ratio of components, the nature of the metal and temperature, they are homogeneous systems (liquid or solid solutions, solid intermetallic compounds) or heterogeneous.

For example, for Ga-Hg in the range of 28-204 °C, there are two immiscible liquid phases - a solution of Ga in Hg and a solution of Hg in Ga.

Solubility (at. %) of metals in mercury at 250 C is: In-70.3, Tl-43.7, Cd-10.1, Zn-6.4, Pb-1.9, Bi-1.6, Sn-1.2, Ga-3.6 Mg-3.0, Au-0.13, Ag-0.078, Al-1.5*10-2, Mn-3.7*10-3, Cu-7 .4*10-3, Ni-1.5*10-5, Ti-2.1*10-5, Zr-2.3*10-6, Co-1.1*10-7, Fe-1 .0*10-7, Pt-3.1*10-7.

The eutectic Hg-Tl (8.55 at.% Tl) with a melting point of -59°C is the most fusible metal alloy. When mercury is applied to the surface of metals and platinum, which are noticeably soluble in it, a wetting film of liquid amalgam is formed; this process called amalgamation.

Solid intermetallic compounds (sometimes called mercurides) are formed in most of the studied systems - mercury.

So, with Mg, mercury forms MgHg2, MgHg, Mg5Hg3, Mg2Hg, Mg5Hg2, Mg3Hg. The melting point of mercurides is higher than that of mercury, and sometimes even higher than that of the second component. For example, for LiHg it is 596 °C. They do not form mercurides, for example, Zn, Al, Ga, Pb, Bi, Sb.

When the amalgam is heated, the mercury evaporates. From metal amalgams with a high boiling point, mercury can be removed almost completely by heating. Because the dissolved metal in the liquid amalgam is crushed to the atomic state and a dense metal oxide film is not formed on the surface of the alloy, most amalgams are chemically very active. Thus, in amalgam, in contrast to a compact metal, it quickly reacts with O2 in air at room temperature.

Amalgams of low-melting metals (Ga, In, Tl, Sn, Cd, etc.) are easily formed when they are heated with mercury. Alkali metals interact with Hg with a significant release of heat; therefore, when obtaining amalgams, they are added to mercury in small portions. Gold, on the surface of which there is no oxide film, when in contact with mercury, it instantly forms an amalgam, which can be removed by the action of HNO3.

When heated amalgam cuprum, silver, gold etc. mercury is distilled off. does not form an amalgam, so mercury can be transported in steel vessels.

Receipt

Amalgam (Amalgams) is

The formation of amalgams of most metals is prevented by an oxide film on their surface. Therefore, for the preparation of amalgam, electrochemical separation of metal on a mercury cathode, removal of a protective film with the help of various reagents, reactions of displacement of mercury from solutions of its salts by metals, etc. are often used.

Yes, amalgam aluminum formed by the action of processed hydrochloric acid A1 to Hg(NO3)2 solution. Preparation of amalgam (except for precious metal amalgams) is advisable to carry out in an inert atmosphere or under a layer of protective liquid, because. Metals dissolved in mercury are easily oxidized by atmospheric O2.

Obtained by the interaction of the Metal with mercury (when the surface of the Metal is wetted with mercury) at ordinary temperatures or by heating, by electrolytic separation of the Metal or a cationic complex on a mercury cathode, or by other methods. Alkaline and alkaline earth metals and some other elements form stable compounds with mercury.

Under the action of sodium amalgam on concentrated solutions of ammonium salts and during the electrolysis of these solutions with a mercury cathode, ammonium amalgam is formed, in which the neutral particle NH04 behaves like a metal atom. At room temperature, this Amalgam rapidly decomposes releasing NH3 and H2.

Application

Amalgam (Amalgams) is

Using the methods of amalgam metallurgy, Ga, In, Tl, Pb, Zn, Sb, REE and other elements are isolated and subjected to deep purification in electrolyzers with a mercury cathode, extracted from the products of processing of polymetallic ores Cd, Cu, Ag, etc., receive powdered metals and alloys, incl. alloys of components with high melting points (Ti-Zr, W-Zr, etc.) and with very different melting and boiling points (Cd-Pd, Cd-Ti, etc.).

Sodium amalgam is used in the preparation of high purity NaOH.

Alkali metal amalgam and Zn-reducing agents in organic synthesis. Amalgams are used in various devices (normal Weston elements, electrodes in polarographs, etc.).

Amalgam is used in the gilding of metal products, in the production of mirrors.

Amalgams of alkali metals and zinc are used in chemistry as reducing agents.

Amalgam is used in the electrolytic production of rare Metals, the extraction of certain Metals from ores.

amalgam Silver used in dentistry as a material for dental fillings.

Amalgam is used in cold welding in microelectronics.

The most famous Amalgam is the mirror guide, the tin Amalgam. Tin-zinc Amalgam is used for rubbing the cushions of electrical machines in order to enhance their effect. The most common and suitable for this purpose, the so-called Kinmayer Amalgam consists of 2 parts of mercury, 1 part of mercury. Zinc and 1 h. Tin.

Amalgamation is carried out on a small scale in the workshops of gilders and coppersmiths, where (when gilding through fire) they cover gold amalgam, bronze, brass, nickel silver, etc .; In this case, the amalgam is superimposed on the surface of metal objects, which are then placed in an oven, at which mercury evaporates and sticks to the surface of the Metal; things gilded in this way are polished.

On an enormous scale, amalgamation is carried out in factories in order to extract Metals from ores. In chemical research, sodium amalgam is often used in those cases where the reduction reaction is carried out in an alkaline medium; in this case, the active principle of chemical interaction is the liberated hydrogen of water, on which the named Amalgam acts like free sodium, but only much less energetically.

Amalgam in dentistry

Amalgam is the most durable filling material that has been used in dentistry for over 100 years.

During this composition, Amalgam has undergone many changes. In dentistry, copper and silver amalgam are used. At present, almost all countries use a silver amalgam with a significant addition of cuprum, the so-called high-copper amalgams.

Amalgams are most widely used in pediatric practice. They are produced by the Industry in the form of sawdust, tablets, as well as amalgamated alloys.

The Silver Amalgam is composed of Mercury, Silver, Tin, Zinc etc. Silver gives Amalgam hardness, slows down Process hardening, increases strength and ensures the fit of the seal to the edges of the cavity.

The advantage of the silver Amalgam is its hardness, plasticity, the ability not to change the color of the tooth (Amalgams of the latest generations), it does not collapse and does not change in the oral cavity. The disadvantages of Amalgam are poor adhesion, high thermal conductivity, shrinkage and the presence of mercury in its composition, which, as is known, can have a toxic effect.

The issue of the adverse effects of mercury has been discussed since the beginning of the use of amalgam fillings. It has been established that mercury from Amalgam enters the oral fluid, and then into the body. However, the amount of mercury entering the body from fillings (even if there are 7-10 fillings) does not exceed the maximum allowable doses. There is a possibility of intoxication of employees dental offices which requires careful compliance with safety standards and requirements.

Dental Amalgam is a special type of Amalgam used as a filling material.

Amalgam alloy is a special alloy in powder form for creating dental amalgam. Silver, Copper, Tin are used as alloy components, sometimes, in smaller quantities, palladium, platinum, indium, villages.

Dental amalgam is one of the oldest filling materials. The first mention of its use dates back to 1800. Its popularity throughout the world is due to its ease of use, as well as the reliability of restorations, especially in the lateral areas, and the low cost of components. Despite such a long Period application of Amalgam, its alloy remained almost unchanged until the 60s of the XX century. Around 1960, a high cuprum amalgam was introduced. Currently, most alloys belong to this group.

Functions of the components of the amalgam alloy.

Silver provides strength and resistance to corrosion and causes expansion when solidified.

Tin causes shrinkage during curing, reduces strength and corrosion resistance, and increases curing time.

Copper at a content of less than 6% plays the same role as Silver. Such Amalgams (alloys) are called conventional, or low Cuprum.

Zinc in the Amalgam Manufacturing Process reduces the oxidation of other alloy Metals. Amalgams with a zinc content of more than 0.01% are called zinc-containing. The role of Zinc has been debated for many years, and recent studies have proven the longevity of Zinc Amalgam fillings. However, if during filling the cavity is contaminated with moisture or saliva, there is a significant increase in the volume of the filling.

Other Metals are added in a volume not exceeding a few percent and do not drastically change the properties of the Amalgam.

Amalgam classification

The size and shape of the alloy particles.

1. Needle, or traditional (usual). Such an alloy powder is obtained by grinding an ingot of an amalgam alloy on lathe to get sawdust. It is characterized by rigidity when packing.

2. Spherical - obtained by spraying molten Amalgam in an inert gas. Requires less mercury for the curing reaction, i.e. has better final physical properties. It is characterized by softness during packing, which is not always convenient.

3. Mixed - obtained by mixing powders of the first two types. "Packability" of Amalgam is regulated by changing the proportions of these components.

1. Amalgam alloys with a low content of Cuprum (silver) have in their composition less than 6% Cuprum (CSTA). Before 1960 almost all Amalgams were of this type. Schematically, the reaction proceeds as follows:

excess Ag3Sn (gamma) + Hg = unreacted Ag3Sn (gamma) + + Ag2Hg3 (gamma-1) + Sn8Hg (gamma-2), OR

y + Hg = g + 7, + 72

2. Amalgam alloys with a high content of Cuprum (copper) usually have 10-30% Cuprum in their composition (CSTA-43, "Tytin", "Contour", Kerr; "Septalloy", Septodont). Most modern amalgams have this composition.

There are several reasons for this.

Firstly, with a high content of Cuprum, there is no reaction between Tin and mercury, i.e., the weakest and most corrosive gamma-2 phase is not formed.

Secondly, Copper replaces some of the Silver in the alloy, which makes Amalgam cheaper. Schematically prote reaction corrosion blowing way.

excess AgSnCu (alloy) + Hg = unreacted alloy + + Ag2Hg3 (gamma-1) + Cu^Sn,..

Amalgams can be described as containing a y2 phase or as not containing it. Amalgams with a low cuprum content have an Hg-Sn(g2) phase in their composition, which worsens their physical properties.

All Amalgams with a high content of Cuprum do not contain the y2-phase a few hours after mixing.

Amalgams with a zinc concentration of more than 0.01% are called zinc-containing (Dispersalloy, Dentsply).

Such Amalgams clinically have high strength, durability and good marginal fit. However, contact with the moisture of such Amalgam prior to its condensation in the oral cavity causes a significant (several hundred micrometers per centimeter) expansion within a few days. This is due to the formation of hydrogen in the Amalgam structure from moisture in the presence of Zinc, which causes a dimensional change. This problem can be avoided by using Amalgams that do not contain hydrogen

Amalgam properties

Amalgams have both positive and negative properties.

Positive properties include high strength, ductility, resistance to abrasion, antiseptic properties of Silver, the ability of Amalgam to cause increased mineralization of hard tissues at the contact boundary, resistance to moisture, which makes Amalgam indispensable for work with children, They are hard, chemically resistant, harden at 37 °C and provide the longest life of fillings.

The negative qualities can be called a pronounced electrical conductivity and high thermal conductivity, which causes a mismatch in thermal coefficients. Two metals with different electronegativity in an electrolyte form a galvanic cell. Saliva is an electrolyte in the mouth, so placing any other non-amalgam structure in the mouth will create an electrical potential, which can cause discomfort, as well as accelerate the corrosion of the more electronegative metal. Amalgams shrink when mercury is deficient, which does not produce a perfect filling. If there are gold dentures in the oral cavity corrosion onks, they can enter into an amalgamation reaction. Amalgam is highly susceptible to corrosion. It has no aesthetic qualities, and in some cases can lead to poisoning of the body, does not match the color of the teeth and poor adhesion to the hard tissues of the tooth. A well-polished Amalgam has a metallic sheen that gradually fades and the filling tarnishes. For filling of chewing teeth, especially in the maxilla, an amalgam filling can be a good alternative to a composite restoration.

Indications for the use of amalgams: cavities 1; 2; 5th grade.

- mechanical properties.

All Amalgams are characterized by good mechanical properties. Depending on the shape of the alloy particles and their composition, the compressive strength varies from 390 to 590 MPa, the diametral strength varies from 122 to 148 MPa, the modulus of elasticity from 41 to 56 GPa, and the static deformation from 0.1 to 2.5%. Spherical Amalgams with a high cuprum content are distinguished by the greatest strength, both immediately after hardening and after a week.

The coefficient of thermal expansion of Amalgam is ten times higher than that of a tooth. This effect should be taken into account when placing metal fillings. To reduce temperature sensitivity in this case, a cement gasket and insulating varnish can.

Dimensional changes in Amalgam are generally small. Shrinkage during curing is negligible, especially in amalgams with a high Cuprum content. However, a Zinc Amalgam filling with a low Cuprum content may increase in volume by 400 microns in the first week. This is due to the ingress of moisture into the cavity of the tooth before placing the filling and can cause severe pain and even split the tooth.

The strength of the restored chips of old amalgam fillings will be 50% lower than the original ones. Adding a second portion of Amalgam to a filling in one visit gives 75% of the strength of a solid filling. The preparation of the cavity in this case should be carried out according to all the rules of mechanical retention.

Mercury is an essential component of Amalgam, its initial content depends on the composition, shape and size of the alloy particles. For the formation of dental amalgam, wetting the surface of the powder particles with mercury is required. Typically, the initial content of mercury, depending on the properties of the powder, ranges from 40 to 53% by weight. Needle Amalgams with low Cuprum content require most mercury, spherical amalgams with a high mercury content are the least. The final content of mercury in amalgams is 37-48% and depends on its initial content and the filling technique.

The maximum permissible concentration of mercury in the air for the occurrence of a negative effect is 50 µg/m3. The concentration of mercury vapor during the application of freshly mixed Amalgam is significantly less than this value, however, there are a number of cases where patients have a pronounced reaction with typical symptoms of allergy to the presence of Amalgam in the mouth.

Mercury fumes can also occur during the act of chewing and corrosion of the Amalgam, however, it has been found that the total intake of mercury from amalgam fillings into the body is significantly lower than the level established by WHO (30 µg / day). carbamide.

- biocompatibility

The biocompatibility of Amalgam has been the subject of intense study for decades. Amalgam fillings are not currently considered to cause any harm to the health of patients, except in rare cases of hypersensitivity. However, many researchers rightly believe that mercury from dental amalgams can pose a health risk to dental staff, patients, and the environment. Based on the toxicological effect of mercury on the body, three forms of mercury can be considered:

Elemental mercury (liquid or vapour);

Inorganic mercury compounds;

Organic compounds of mercury.

Liquid mercury is relatively poorly absorbed through the skin and mucous membranes. When absorbed, mercury is mainly ionized and is easily excreted by the kidneys. The previously widespread practice of squeezing mercury from the mixed Amalgam by hand did not lead to any serious health problems for the operator. Liquid mercury does not pose a risk to the health of the patient if its particles have been swallowed. In this case, mercury comes out unchanged with faeces.

Mercury vapor is much more hazardous to health, as it is quickly absorbed into the blood through the lungs, remaining for several minutes in a non-ionized, i.e. lipophilic, form. The latter allows it to penetrate tissue barriers, such as the blood-brain barrier.

Thus, mercury can accumulate in tissues. The greatest danger is the accumulation of mercury in brain and nerve cells. At high concentrations of mercury, nerve conduction is damaged, which leads to impaired Works brain, up to death. At lower concentrations, anxiety, tremor, loss of concentration, and impairment of individual functions are noted. There is a real risk of health damage for dental staff working in a room with a high mercury content. The amount of mercury evaporating from amalgam fillings, even with a large amount of mercury in the patient's mouth, is significantly lower than the amount that can be harmful to health.

The inorganic mercury compounds present in Dental Amalgam have low or very low toxicity. They are poorly absorbed, do not accumulate in body tissues and are well excreted. Some inorganic mercury compounds are used as an external antibacterial agent. For the "control" of mercury, it is usually used, since when they interact, mercury sulfide is formed, which does not pose a danger to the environment.

Organic mercury compounds are very toxic in low concentrations, but none of these compounds are formed in the oral cavity when dental Amalgam is used. Of much greater concern is the release of mercury compounds in water through sewers into the environment. Once in the watercourse, organic mercury compounds end up in large bodies of water, where microorganisms convert them into inorganic forms, such as mercury chloride. These compounds are then taken up by living organisms. Through the food chain, mercury enters through seafood to humans, causing poisoning.

Corrosion

Corrosion is understood as the electrochemical destruction of the Metal when interacting with the surrounding substances.

All Amalgams are subject to corrosion. On the one hand, corrosion leads to a deterioration in the mechanical properties of the Amalgam, on the other hand, corrosion products fill the microcracks between the tooth wall and the filling.

Amalgams that do not corrode the y2 phase are much less corrosive than Amalgams with a low Cuprum content. The presence of various metals and alloys in the oral cavity contributes to increased corrosion, especially in close proximity to each other. The contact of the old Amalgam with the new one also has the same effect. On the other hand, Amalgam corrosion has a positive aspect - corrosion products clog the marginal gap and provide a tighter fit of the restoration.

clinical properties. Extensive laboratory and clinical studies have confirmed the corrosion reliability of Amalgam as a filling material.

Receipt

To obtain Amalgam in dentistry, highly ground particles are used, which are an alloy of several Metals, and mercury itself.

The largest part of the alloy of traditional dental Amalgam is Silver (about 70%) and Tin (about 25%). The rest of the alloy can be Zinc, Copper and mercury. Silver is the main component of the alloy; it is present in conjunction with Tin in the form of the intermetallic compound Ag3Sn, also called the gamma phase (Ag3Sn is the third pure phase in the system, hence the Greek symbol gamma).

The gamma phase readily reacts with mercury to form Amalgam. The addition of Cuprum increases the strength and hardness of the Amalgam, but a more pronounced effect occurs with an increase in the concentration of Cuprum over 6%. Zinc in the composition of the alloy is not believed to play any important role; small amounts of mercury are added to increase the rate of the curing reaction.

The alloy is usually ground to particles of several tens of microns and is produced in the form of a regular or compressed powder.

The mercury intended for the preparation of the Amalgam must be very pure, as any contamination of the surface will interfere with the curing reaction.

To obtain a well-formed mixture, mercury is taken in excess. The mass ratio of sawdust and mercury depends on the Silver content in the alloy and is 5:4 for Amalgam with a low Silver content and 5:8 for Amalgam with a high Silver content (the ratio is indicated in the instructions). When mercury is deficient, Amalgams show high shrinkage, a grainy surface and poor marginal fit. Excess mercury is removed from the mixture before it is introduced into the tooth cavity. With an excess of mercury, the strength decreases, the fluidity of the seal increases, the hardening period lengthens, the color changes, and the corrosion resistance of the seal decreases.

The molding mass is prepared in a glass mortar, rubbing the mass with a pestle until a homogeneous plastic mass is formed that adheres to the wall of the mortar. The mass is prepared for 1.5-2 minutes. With a force of 10-15 N, 100 revolutions of the pestle are sufficient. It is necessary to work in rubber gloves. In the process of expansion of the mixture, neither mercury nor sawdust can be added, as this disrupts the already beginning structuring of the material, sharply reduces the strength and corrosion resistance of the seal.

In order to obtain a homogeneous mass on the surface of the mortar and working surface pestle create roughness. To standardize the conditions for the preparation of molding material and create hygiene conditions using mechanical mixers-amalgators. The preparation of the molding mass is carried out at a temperature of 22 ± 2 °C according to the instructions of the Amalgam manufacturer.

Amalgams should not expand much during hardening, as they can cause pain and lead to a violation of the thinned walls of the tooth. With good quality Amalgam after 24 hours, its expansion is 4-10 microns per 1 cm of length.

To obtain a dental amalgam, an amalgam alloy is mixed with mercury. During the mixing process, mercury reacts with the alloy filings and causes a curing reaction. For the convenience of describing these Processes, conventions the most important compounds of this reaction.

The gamma (y) phase denotes the alloy of Silver and Tin Ag3Sn, the gamma-1 (y:) phase denotes the compound of Silver and mercury Ag2Hg3, and the gamma-2 (y2) phase denotes Tin and mercury Sn8Hg. The gamma-2 phase is the weakest and most susceptible to corrosion. In amalgams with a high cuprum content, with proper mixing, the gamma-2 phase either does not form at all or is eliminated a few hours after mixing.

The Amalgam solidification reaction, based on the interaction of the gamma phase (Ag3Sn) and mercury, initiates active mixing of these substances. During the reaction, the surface layer of the alloy particles dissolves into the Amalgam, which results in the formation of two new phases that become solid at room temperature, while the interior of the alloy remains unreacted:

Ag3Sn + Hg = Ag3Sn + Ag2Hg3 + Sn7Hg

Ag2Hg3 and Sn7Hg make up the Amalgam matrix and are called the gamma1 and gamma2 phases, respectively. The cured material is unreacted gamma phase particles held in a gamma 1 phase matrix interspersed with gamma 2 phase.

Copper in the alloy is present in the form of individual sections of Cu3Sn and remains, basically, in the same form in the composition of the Amalgam.

Amalgam representatives

Silver Amalgam SSTA-01. Finely dispersed (powder particle size is not more than 160 microns). The composition of the powder (or sawdust) is Silver 68%, Tin 28%, Zinc 1%, Copper 3%. Comes with mercury.

The curing time of silver Amalgam is one and a half to two hours, but the full completion can be seen only after 6 to 8 hours. This becomes the reason that after filling the patient should not eat for 1.5 - 2 hours, the next 6 - 8 hours he should not chew on the filled tooth. The long curing time has determined that polishing and grinding is carried out only the next day. For grinding, finishers, carborundum stones, strips are used, and for polishing - felt or rubber heads, as well as brushes and polishers. The smooth surface of the amalgam filling significantly increases some of its qualities (hardness, marginal fit, corrosion resistance, service life of the filling), so the final processing must be carried out without fail. The ideal treatment of the tooth appears after the surface becomes shiny and smooth, and there is no gap between the filling and the tooth.

The method of application, as well as the indications, corresponds to copper amalgam.

High-copper Amalgam SR MOIT-58. The composition includes - Silver - 58%, Tin - 27%, Copper - 11.5%, Indium - 3%, Titanium - 0.5%. The strength of such an Amalgam is 3 times higher than the others. The properties of Amalgam can be improved by reducing the amount of gamma 1 and especially gamma 2 phase. Removing the latter would greatly increase the corrosion resistance and reduce the creep rate. Increasing the amount of Cuprum in the alloy led to a modification of the setting reaction, during which almost all of the low-use gamma-2 phase disappeared.

Amalgam with high corrosion of Cuprum, in comparison with traditional amalgam, has a number of positive changes, such as:

Higher compressive strength;

Faster full hardening;

Reduced creep;

Improved corrosion resistance.

Tableted Copper Amalgam - Copper approximately 30% and mercury 70% with the addition of Tin 1.5-2% and Silver. It is produced in the form of briquettes - tiles 5x5 mm. Prepared by heating over an alcohol lamp.

Amadenp (Silver Amalgam) - a set of single doses of mercury and powder in capsules.

Capsulated copper amalgam - a set of single doses of mercury and powder in capsules.

Vivacap, Amalcap Plus Non-Gamma-2 (Vivadent). These are Amalgams with a high Silver content. Does not contain gamma-2 phase. The mercury-tin phase (gamma-2 phase) makes Amalgam more susceptible to corrosion, as it is the most electrochemically active. Mercury is released from this phase to the greatest extent. The mercury released when this phase is disturbed can be adsorbed by the silver-tin phase, which leads to expansion and protrusion of the edges of the filling surface.

amalgam

well. chemical descent, connection, alloy of other metals with mercury, casket. The silver bag is found in nature as an ore; gold is made for weeding through the fire. Amalgam, sortuchkovy, trigger. Amalgamated gold, silver, lowered with mercury. Amalgamate what, with what, lower with mercury, sort. Amalgamation, amalgamation action by verb;

the very sort;

extraction of gold and silver from ores by descent with mercury, which is then driven away by fire.

Explanatory dictionary of the Russian language. D.N. Ushakov

amalgam

amalgams, g. (from Greek malagma - softening).

The connection of some metal with mercury (chem.). Amalgam dental filling.

trans. A mixture of dissimilar things.

Explanatory dictionary of the Russian language. S.I. Ozhegov, N.Yu. Shvedova.

amalgam

Liquid, semi-liquid or solid alloy of mercury with other metals (special).

trans. A heterogeneous mixture, a combination of something. (book).

adj. amalgam, -th, -th (to 1 value).

New explanatory and derivational dictionary of the Russian language, T. F. Efremova.

amalgam

1. An alloy of some metal with mercury.

   trans. Combination, combination. heterogeneous.

A thin layer of an alloy of mercury and tin covering reverse side mirrors.

Encyclopedic Dictionary, 1998

amalgam

AMALGAMA (medieval lat. amalgama - alloy) an alloy of mercury with other metals. Amalgam is used, for example, in gilding, in the production of mirrors, in non-ferrous metallurgy (amalgamation).

Amalgam

an alloy, one of the components of which is mercury. Depending on the ratio of mercury to other metals, diamonds can be (at room temperature) liquid, semi-liquid, or solid. The formation of A. occurs when the metal is wetted with mercury as a result of the diffusion of mercury into the metal. From liquid and semi-liquid A. (excess mercury contains a small amount of metal), mercury is removed by filtration through suede under pressure; solid aluminum decomposes into its component parts when heated (traces of mercury are removed from the metal during subsequent melting). A. is used in the gilding of metal products, in the manufacture of mirrors, in dentistry, and also as reducing agents (see Restoration of metals). See also Amalgamation.

Lit .: Plaksin I.N., Metallurgy of noble metals, M., 1958.

Wikipedia

Amalgam

Amalgam- liquid or hard alloys of mercury with other metals. Also, the amalgam can be a solution of ionic complexes behaving similarly to metals (for example, ammonium).

Amalgam (disambiguation)

Amalgam (- alloy).

• Amalgam is an alloy of some metal with mercury.
• "Amalgam" is a company that works with foreign films. In particular, released the release of the film "The Fifth Element" on DVD.
• "Amalgam" is the professional name for one of the filling materials in dentistry.
• Linguistic laboratory "Amalgama" - a site that translates foreign songs into Russian.
• Amalgam is a rock band formed in the late 1980s in Krasnoyarsk.
• Amalgam in category theory is a concept dual to the Cartesian square.
• An amalgam in universal algebra is a family of subsystems of some algebraic system whose pairwise intersection is non-empty and is a subsystem of each of them.
  • An amalgam of groups is a family of groups whose pairwise intersection is non-empty and is a subgroup.
  • A semigroup amalgam is an amalgam of semigroups.

Amalgam (dentistry)

"Amalgam"- the professional name of one of the filling materials, the properties of which use the ability of mercury to dissolve certain metals (See article: Amalgam). Amalgam is the most durable filling material that has been used in dentistry for over 100 years. During this period, the composition of the amalgam has undergone many changes. In dentistry, copper and silver amalgam are used. Currently, almost all countries use silver amalgam with a significant addition of copper, the so-called high-copper amalgams.

Examples of the use of the word amalgam in the literature.

Finally from the last retort shining amalgam poured onto a metal dish.

Tell me why such a design was given to you just for a day in the land of lakes, whose amalgam store space for the future?

If you ever forget the sum of the angles of a triangle or the area in a vicious circle, come back here: amalgam the mirrors in the bathroom are hidden by a volapyuk heavily spiced with sweet Cyrillic and a top secret thought about death.

Lies, falsification, forgery, forensic amalgam assumed proportions unprecedented in history and, as the Kirov case shows, they directly threaten the Stalinist regime.

But although Stalin's handymen diligently glue him to Trotskyism, amalgam this one is wholly invented, in essence Bukharin is alien both to the Trotskyist-Zinoviev bloc and, of course, to Stalinist politics.

Meanwhile, the assistant was engaged in external appeal amalgams across the cinnabar fields.

He longs to undress, throw off his cloth shell, collapse into bed, cling to a living bone, like a hot mirror, with whose amalgams do not scrape off tenderness with a finger.

By sloppily assembling the process, the GPU obviously overestimated its strength and, in any case, lost sight of the fact that my son and I could manage to deliver a crushing blow, at least to that part of the Moscow amalgams which concerns our life and activities abroad.

In the future, the point is amalgam, the essence in reflected yesterday in a column mercury will fall, in the summer - a bee will buzz.

And it turned out that mercury, hitting the gilded surfaces, instantly turned a thin layer of gilding into amalgam silver color.

I took out of the cupboard what were lying in order: fake seals, boxes of colored sealing wax, a light bulb for heating, amalgam and the whole set of tools for opening packages, consisting of lancets, tweezers, sharply honed knuckles, etc.

But in the corridor where he went out, after delicately giving his neighbor in the compartment the opportunity to get ready for bed, he could admire his own reflection in the large window of the carriage, covered with black amalgam night.

Every stone on the pavement seemed to be covered with a magical amalgam reflecting his youth.

The little things thus obtained were sawn off, their inner surface, with the help of simple chemistry, was covered with a shiny amalgam, and that was the end of production.

When I finally fell asleep, my dream was amalgam of the same material, including term in my old cell and picking at the door.

what is amalgam

1. Mirror cover. Alloy of mercury with other metalamium
2. This is the thing on the other side of the mirror
3. Amalgam (cf. - century lat. amalgama alloy) liquid or solid alloys of mercury with other metals. Also, the amalgam can be a solution of ionic complexes behaving similarly to metals (for example, ammonium).
4. Liquid or solid alloys of mercury with other metals. Also, the amalgam can be a solution of ionic complexes behaving similarly to metals (for example, ammonium).
5. AMALGAMA is a coating for a mirror.
6. AMALGAMA (medieval lat. amalgama - alloy), an alloy of mercury with other metals. Amalgam is used, for example. , in gilding, in the production of mirrors, in non-ferrous metallurgy (amalgamation).
7. that's what's on the other side of the mirror...
8. something like mercury
9. Amalgam - definitions on the Internet:
   Amalgam is the professional name for one of the filling materials...
   en.wikipedia.org/wiki/Amalgam_(dentistry)

   Amalgam (cf. - century amalgama alloy) liquid or solid alloys of mercury with other ...
   en.wikipedia.org/wiki/Amalgam

   well. chemical descent, connection, alloy of other metals with mercury, casket. ..
   voc.metromir.ru/voc_dal/P002.HTM

   filling material for permanent fillings
   www.zubnoy.spb.ru/slovar.html

   any alloy containing mercury. In dentistry, amalgam fillings...
   biotec.ru/index/product/gloss/
   more specifically:
   1. Amalgam (cf. - century lat. amalgama alloy) liquid or hard alloys mercury with other metals. It is obtained by the interaction of metal with mercury (when the metal surface is wetted with mercury) at ordinary temperatures or by heating, by electrolytic precipitation of metal on a mercury cathode, or by other methods. Alkali and alkaline earth metals and some other elements form stable compounds with mercury. When amalgams of copper, silver, gold, etc. are heated, mercury is distilled off. Iron does not form an amalgam, so mercury can be transported in steel vessels. Amalgam is used in the gilding of metal products, in the production of mirrors. Amalgam of alkali metals and zinc is used in chemistry as reducing agents. Amalgam is used in the electrolytic production of rare metals, the extraction of certain metals from ores.

   2. Amalgam is the professional name for one of the filling materials, the properties of which use the ability of mercury to dissolve certain metals. Amalgam is the most durable filling material that has been used in dentistry for over 100 years. During this period, the composition of the amalgam has undergone many changes. In dentistry, copper and silver amalgam are used. Currently, almost all countries use a silver amalgam with a significant addition of copper, the so-called high-copper amalgams.

   Silver amalgam consists of mercury, silver, tin, zinc, etc. Silver gives the amalgam hardness, tin slows down the hardening process, copper increases strength and ensures that the filling adheres to the edges of the cavity.

   The advantage of silver amalgam is its hardness, plasticity, the ability not to change the color of the tooth (amalgams of the latest generations), it does not collapse and does not change in the oral cavity. The disadvantages of amalgam are poor adhesion, high thermal conductivity, shrinkage and the presence of mercury in its composition, which, as is known, can have a toxic effect.

   The issue of the adverse effects of mercury has been discussed since the beginning of the use of amalgam fillings. It has been established that mercury from the amalgam enters the oral fluid, and then into the body. However, the amount of mercury entering the body from fillings (even if there are 7-10 fillings) does not exceed the maximum allowable doses. There is a possibility of intoxication of employees of dental offices, which requires careful observance of the norms and requirements of safety rules.
   http://ru.wikipedia.org/wiki/Amalgam

10. As far as I know, amalgam is a mirror layer on glass! Other values ​​are also possible.
11. Amalgam is an alloy in which mercury is one of the components. Depending on the ratio of mercury to other metals, diamonds can be (at room temperature) liquid, semi-liquid, or solid. The formation of A. occurs when the metal is wetted with mercury as a result of the diffusion of mercury into the metal. From liquid and semi-liquid A. (excess mercury contains a small amount of metal), mercury is removed by filtration through suede under pressure; solid aluminum decomposes into its constituent parts when heated (traces of mercury are removed from the metal during subsequent melting). A. is used in the gilding of metal products, in the manufacture of mirrors, in dentistry, and also as reducing agents.
12. mixture of mercury and silver