Dentistry amalgams

Dentistry. Mercury is used in dental amalgams for fillings in teeth (see Dental materials). Dental uses have accounted for 2—4% of total U.S. mercury consumption since 1980 and generally 3—6% before that time (3). Dental amalgams used to fill cavities in teeth are approximately 50% mercury by weight. Dental use of mercury can be expected to continue to decrease, in part because of more effective cavity prevention as well as development and increasing use of alternative dental materials such as plastics and ceramics, and increasing awareness of the environmental and health effects of mercury. 

There have been numerous reports of possible allergic reactions to mercury and mercury salts and to the mercury, silver and copper in dental amalgam as well as to amalgam corrosion products Studies of the release of mercury by amalgams into distilled water, saline and artificial saliva tend to be conflicting and contradictory but, overall, the data indicate that mercury release drops with time due to film formation and is less than the acceptable daily intake for mercury in food . Further, while metallic mercury can sensitise, sensitisation of patients to mercury by dental amalgam appears to be a rare occurrence. Nevertheless, there is a growing trend to develop polymer-based posterior restorative materials in order to eliminate the use of mercury in dentistry. 

However, these values are less than those recorded for composite resins used in dentistry. Goldman (1985) reports values of 29 to 49 MPa for anterior composite resins and Lloyd Adamson (1987) values of 76 to 125 MPa for posterior composite resins. A typical amalgam has a flexural strength of 6 MPa (Lloyd Adamson, 1987) (Table 5.16). However, the flexural strengths of some glass-ionomer cements increase with time and values as high as 59 MPa (after 3 months) and 70 MPa (after 7 days) have been reported (Pearson Atkinson, 1991). 

Known to the ancients Soft anticorrosive precious metal whose name comes from the Latin meaning shining dawn long used as currency and in jewelry also in electronics and dentistry. The only metal liquid at room temperature chief ore is cinnabar found mostly in Italy and Spain dissolves other metals to form amalgams useful to industry highly toxic. 

Amalgams. Liquid mercury is a fairly good solvent for all metals except iron and platinum. The alloys that are formed by dissolving metals in mercury are called amalgams, many of which involve inter-metallic compounds of the type MHg, where x is quite variable. Aside from their many applications in scientific work, amalgams are used in dentistry and in connection with the metallurgy of silver and gold. 

The alloys of mercury are called amalgams. Amalgams of silver, gold, and tin are used in dentistry. Mercury does not wet iron, and it is usually shipped and stored in iron bottles, called flasks, which hold 76 lbs. of the metal. 

Osborne JW, Albino JE. Psychological and medical effects of mercury intake from dental amalgam. A status report for the American Journal of Dentistry. Am J Dent 1999 12(3) 151-6. 

But even as recendy as the mid-20th cenmry, there was relatively litde concern about mercury metal and many mercury compounds. High school chemistry students often played with tiny droplets of mercury in the laboratory. They used mercury to coat pennies and other pieces of metal. Mercury was also widely used in dentistry. It was used to make amalgams, alloys of mercury with other metals, used to fill teeth. Most people even today are likely to have dental fillings that contain a small amount of mercury metal. The question of whether mercury is still safe to use in... 

This relationship between allergy and metallic biomaterials has also been confirmed for alloys used in dentistry Ni, Cr and Co in non-precious alloys (Hildebrand et al. 1989a, 1989b), and Hg and Ag in dental amalgams (Veronetal. 1986 Horsted-Bind-slev et al. 1997 Sandborgh-Englund et al. 

Cobalt salts and oxides are used in the glass industry, for paints and colored pottery (10). They are also used as fodder additives for ruminants, as fertilizers, as catalysts in chemistry, as vitamin and radiation sources ( Co in medicine), as amalgam in dentistry, and as antidotes of cyanides in the form of ethylenediamine tetraacetic acid (EDTA) complexes. Several years ago, C0SO4, C0CI2, and Co(OAc)2 were used as foam stabilizers in the brewing of malt beverages. This is no longer allowed due to the cardiovascular diseases that were induced. 

Dentistry. Silver is also used in dentistry either as Ag-Sn-Hg or Ag-Sn-Cu-Hg silver alloys owing to their small expansion during setting, which is suitable for making dental amalgams. 

In dentistry, the presence of amalgams and various alloys in the mouth poses potential corrosion problems if an electrical cormection occur-s. Growing numbers of dental implants increase the possibility for corrosion in the mouth, and consideration should be given to suprastructure metals that are irsed with implants. 

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