Biocompatibility of dental casting alloys: A review*,**
Section snippets
Alloy composition and microstructure
An alloy is any mixture of 2 or more metals. In dentistry, alloys usually contain at least 4 metals, and often 6 or more. Thus, dental alloys are complex metallurgically. Alloy compositions are diverse, and much of this diversity has developed in the past 20 years as the price of gold has increased and the functional and biologic demands on these alloys have increased. For many years, most dental alloy compositions were based on gold; that is, they contained gold as their major element.
SYSTEMIC TOXICITY OF CASTING ALLOYS
More often than not, the biocompatibilities of casting alloys used in dentistry are not fully known. Thus, it is impossible to give a practitioner a list of “good” and “bad” alloys for dental applications. Rather, the goal of the following sections is to present principles that will guide the reader to make informed judgments about biocompatibility as new information becomes available and new alloys are developed. One fundamental concern about the safety of casting alloys is their ability to
LOCAL TOXICITY OF CASTING ALLOYS
A second major concern about the safety of dental casting alloys is whether elements released can cause toxicity locally, that is adjacent to the restoration. Again, there are several key concepts that should aid the practitioner in assessing the potential of casting alloys to cause local toxicity.
An element must be released from an alloy to cause allergy
No study has shown that allergy to alloys can occur without corrosion and release of metallic ions. At least 1 study has shown that, even in patients with a documented allergy to palladium, placement of palladium in the mouth did not elicit an allergic reaction.39, 40 Presumably, the lack of response was caused by a lack of corrosion of the palladium. This principle further supports the importance of knowing the corrosion properties of an alloy.
Metal ions cannot be allergens by themselves
As far as is known, metal ions cannot act as
Mutagenicity and carcinogenicity are not the same
Mutagenicity describes an alteration of the basepair sequence of DNA (a mutation). Carcinogenicity means that alterations in the DNA have caused a cell to grow and divide inappropriately. Carcinogenicity results from several mutations.62 It is important to understand that not all mutagenic events lead to carcinogenesis. Many mutations are repaired; others occur in irrelevant sections of the DNA; and still others do not have any functional consequence. Mutations occur routinely in our DNA, and
CONCLUSIONS
Because it is not currently possible to know the complete biologic effects of any dental alloy, practitioners must rely on knowledge of the principles of biocompatibility to decide which dental casting alloys they will use. This decision is not an easy one, and it will have financial, legal, technical, and patient satisfaction consequences for the practitioner. In many ways, the decision is philosophical, based on the possible biologic risks of using a particular alloy versus its known clinical
References (71)
Metal release from dental biomaterials
Biomaterials
(1986)- et al.
Study of corrosion between a titanium implant and dental alloys
J Dent
(1994) - et al.
Corrosion properties of soldered joints. Part II: corrosion pattern of dental solder and dental nickel-chromium alloy
J Prosthet Dent
(1991) - et al.
Effect of pH on element release from dental casting alloys
J Prosthet Dent
(1998) - et al.
Biological fate of 103Pd in rats following different routes of exposure
Environ Res
(1974) - et al.
Release of elements from dental casting alloys into cell-culture medium over 10 months
Dent Mater
(1998) - et al.
Precision of and new methods for testing in vitro alloy toxicity
Dent Mater
(1992) - et al.
Gingival reaction on crowns with cast and sintered metal margins: a progressive report
J Prosthet Dent
(1994) - et al.
Nickel chloride and cobalt chloride, two common contact sensitizers, directly induce expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule-1 (ELAM-1) by endothelial cells
J Invest Dermatol
(1993) - et al.
In vitro IL-1beta and TNF-alpha release from THP-1 monocytes in response to metal ions
Dent Mater
(1996)
Influence of metals on IL-6 release in vitro
Biomaterials
Carcinogenicity assessment of selected nickel compounds
Toxicol Appl Pharmacol
The release of elements of dental casting alloys into cell-culture medium
J Dent Res
Corrosion engineering
Cytotoxicity of Au-based dental solders alone and on a substrate alloy
J Biomed Mater Res
Correlation between cytotoxicity and the elements released by dental casting alloys
Int J Prosthodont
Corrosion and cell culture evaluations of nickel-chromium dental casting alloys
J Appl Biomater
Ion release from Ni-Cr-Mo and Co-Cr-Mo casting alloys
Int J Prosthodont
Cytotoxicity of dental alloy extracts and corresponding metal salt solutions
J Dent Res
Element release and cytotoxicity of Pd-Cu binary alloys
Int J Prosthodont
Toxic effects of metals
Different effects of intraperitoneally and orally administered palladium chloride on the hepatic monooxygenase system of male mice
Arch Toxicol Suppl
Cardiovascular actions of palladium compounds in the unanesthetized rat
Environ Health Perspect
Systemic effects of biomaterials
Biomaterials
Size of metallic and polyethylene debris particles in failed cemented total hip replacements
J Bone Joint Surg [Br]
Histology of dog dental tissues with Cu-based crowns
J Dent Res
Release of cobalt from cobalt chromium alloy constructions in the oral cavity of man
Scand J Dent Res
LAMMS and ICP-MS detection of dental metallic compounds in not-discolored human gingiva
J Dent Res
Systemic nickel: the contribution made by stainless-steel cooking utensils
Contact Dermatitis
Serum titanium transport in patients following primary total hip replacement: a 2 year prospective study
Trans Soc Biomater
Serum and urine metal content in patients with fretting corrosion of modular femoral THR components
Trans Soc Biomater
Release of metal ions from dental implant materials in vivo: determination of Al, Co, Cr, Mo, Ni, V, and Ti in organ tissue
J Biomed Mater Res
Cited by (393)
Impact of scandium and terbium on the mechanical properties, corrosion behavior, and biocompatibility of biodegradable Mg-Zn-Zr-Mn alloys
2024, Journal of Magnesium and AlloysZn additions modifying microstructure, thermal parameters and cytotoxicity of Sn-0.7Cu eutectic solder alloys
2023, Materials CharacterizationEffect of cerium on mechanical, metallurgical and biomedical properties of NiCrMoB dental alloy
2023, Journal of Materials Research and TechnologySynthesis of TiO<inf>2</inf> nanostructures and their medical applications
2023, Oxides for Medical ApplicationsPromoted mechanical properties and functionalities via Ta–tailored Ti–Au–Cr shape memory alloys towards biomedical applications
2022, Journal of the Mechanical Behavior of Biomedical Materials
- *
Reprint requests to: DR JOHN C. WATAHA, DEPARTMENT OF ORAL REHABILITATION, MEDICAL COLLEGE OF GEORGIA SCHOOL OF DENTISTRY, AUGUSTA, GA 30912-1260, FAX: (706) 721-8349, E-MAIL: [email protected]
- **
0022-3913/2000/$12.00 + 0. 10/1/104278