Dental nickel

Local sarcomas may develop in humans and domestic animals at sites of nickel implants and prostheses made of nickel. Latency of the implant sarcomas varies from 1 to 30 years in humans (mean, 10 years) and from 1 to 11 years in dogs (mean, 5 years). No cases of malignant tumors are reported at sites of dental nickel prostheses (Kasprzak 1987). 

Figure 17 Simultaneous shear-force AFM (a) (10 im, z-range 300 nm) and (c) (z-range 1.6(im) and apertureless SNOM (b, d) of an abraded dental nickel alloy (a) and (b) before, (c) and (d) after the electrochemical standard leaching test.

Dentistry. Most casting alloys meet the composition and properties criteria of specification no. 5 of the American Dental Association (37) which prescribes four types of alloy systems constituted of gold—silver—copper with addition of platinum, palladium, and 2inc. Composition ranges are specified, as are mechanical properties and minimum fusion temperatures. Wrought alloys for plates also may include the same constituents. Similarly, specification no. 7 prescribes nickel and two types of alloys for dental wires with the same alloy constituents (see Dental materials). 

Gallium-Based Alloys. A gaUium-based alloy has been kitroduced commercially ki Japan as a substitute for dental amalgam, but similar alloy types have previously been associated with abnormal cellular reactions and are not much used elsewhere nickel— gallium alloys have produced carckiomas ki rats (139). The corrosion resistance of the gallium alloys is also marginal. 

GoldJilloys, Wrought Type. Two types of wrought gold alloys were formerly recognized by the ADA specification no. 7 for the fabrication of orthodontic and prosthetic dental appHances, ie, type I, high-precious-metal alloys, and type II, low-precious-metal alloys (gold color). Alloys of this type are seldom used in the United States they have been replaced by stainless steels and nickel—titanium alloys. 

ANSI/ADA specification no. 14 provides a requirement for removable partial dentures of a combined minimum of 85% by weight of chromium, cobalt, and nickel or, for alloys failing to meet that minimum, at least 20% chromium. Bio-compatibiUty is demonstrated by passing the pertinent criteria of ANSI/ADA specification no. 41, Recommended Standard Practices for Biological Evaluation of Dental Materials. 

There is no meaningflil correlation between laboratory corrosion tests and clinical performance, but high in vitro corrosion rates on several high nickel dental prosthetic alloys (163), together with the prevalence of allergy to nickel caused by plated jewelry, gives cause for caution. 

The property most frequently cited in connection with the use of Ti dental or medical appHances is titanium s unique biocompatibiHty. This helps practitioners avoid occasional allergic reactions that occur with nickel or chromium alloys, and removes concerns about the toxic or carcinogenic potential of appHances that contain nickel, chromium, or beryUium. Wrought alloys of titanium are used for orthodontic wires because of their unique elastic... 

Burrows, D. Hypersensitivity to Mercury, Nickel and Chromium in Relation to Dental Materials , International Dental Journal, 36, 30-34 (1986)... 

Sarkar, N. K., Graves, R. A., and Park, J. R. Corrosion of Nickel-Chromium Casting Alloys in Selected Biological Media , Journal of Dental Research, 66, 206 (Abstr. 793) (1987)... 

Magnusson, B., Bergman, M., Bergman, B. and Soremark, R. Nickel Allergy and Nickel Containing Dental Alloys , Scandinavian Journal of Denial Research, 90, 163-167 (1982)... 

Bergman, M., Bergman, B and Soremark, R. Tissue Accummulation of Nickel Released due to Electrochemical Corrosion of Non-precious Dental Casting Alloys , Journal of Oral Rehabilitation 7, 325-300 (1980)... 

Nixon277 compared atomic absorption spectroscopy, flame photometry, mass spectroscopy, and neutron activation analysis as methods for the determination of some 21 trace elements (<100 ppm) in hard dental tissue and dental plaque silver, aluminum, arsenic, gold, barium, chromium, copper, fluoride, iron, lithium, manganese, molybdenum, nickel, lead, rubidium, antimony, selenium, tin, strontium, vanadium, and zinc. Brunelle 278) also described procedures for the determination of about 20 elements in soil using a combination of atomic absorption spectroscopy and neutron activation analysis. 

Nickel-chromium alloys, 77 100-101 dental applications, 8 308, 310 Nickel-chromium-iron alloys, 73 519, 522 Nickel-chromium-molybdenum alloy C, in galvanic series, 7 805t... 

Ni-P adhesion, 9 705. See also Nickel phosphorus entries Ni-P alloys, solderability, 9 707, 708 NIPAm hydrogels, 13 738 Ni-P density, 9 705 Ni-P electrical resistivity, 9 706 Ni-P ferromagnetic properties, 9 706 Nipkow disk, 16 484 Ni-P mechanical properties, 9 706 Niranium N/N, base-metal dental alloy, 8 309t... 

Nickel allergy is an adverse effect of the use of nickel-containing medical apphances, such as orthopedic metal alloys, dental materials, and implants (9), and allergic reactions are common. Nickel allergy and contact dermatitis with nickel-based apphances have been reviewed (10). 

Grimaudo NJ. Biocompatibility of nickel and cobalt dental alloys. Gen Dent 2001 49(5) 498-503. 

Titanium is used in medicine mainly for its mechanical benefits in surgical and dental materials in a host of orthopedic and orthodontic appliances, with or without other metals (for example nickel, cobalt, chromium), and generally without serious adverse effects. Titanium and its alloys are in use as implants in bone surgery (1,2) and in dental materials (3,4). Research on the biocompatibility of metal and tissue continues (5). 

Next-generation metallic biomaterials include porous titanium alloys and porous CoCrMo with elastic moduli that more closely mimic that of human bone nickel-titanium alloys with shape-memory properties for dental braces and medical staples rare earth magnets such as the NdFeB family for dental fixatives and titanium alloys or stainless steel coated with hydroxyapatite for improved bioactivity for bone replacement. The corrosion resistance, biocompatibility, and mechanical properties of many of these materials still must be optimized for example, the toxicity and carcinogenic nature of nickel released from NiTi alloys is a concern. ... 

In Hildebrand HE, Veron C and Martin P (1989a) Nickel Chromium Cobalt dental alloys and allergic reactions an overview. Biomaterials 10 545-548. 

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