Metal crowns and Bio-compatibility to the Oral Tissues
At Pacific Dental Aesthetics we choose not to use metal restorations due to the oral tissue compatibility. Our criteria for choosing restorative materials here are how durable, natural looking, and how practical they are for the dentist and dental laboratory to use.
As the cost of providing dental care escalates, there has been a substantial increase in the substitution of non-precious alloys for gold and precious metals found in porcelain-fused-to-metal crowns. These alloys are frequently 69% to 81% nickel. Nickel hypersensitivity is quite common in the general population and periodontal responses have been associated with nickel-containing crowns in nickel-sensitive individuals. Non-precious alloy crowns cannot be well tolerated in most cases, therefore a history of metal sensitivity should be evaluated.
In addition to nickel, all dental cast alloys release metal ions into the oral environment which have the potential to interact with the oral tissues and can provoke systemic and local allergic reactions. Also, dissimilar metals in the mouth, including different formulations of the “same” metal, create micro-amps of current which could cause oral pain, corrosion of the metal (black mercury amalgam fillings), dry mouth, metallic taste, and erythema (red & swollen gums).
The quality and quantity of the released cations depend upon the type of alloy and various corrosion parameters. In sufficient quantities, released metal ions—particularly Cu, Ni, Be, and abraded micro-particles—can also induce inflammation of the adjacent periodontal tissues and the oral mucous. Allergic reactions due to metallic dental restorations have been documented. Interestingly, from 34% to 65.5% of the patients who are allergic to Ni are also allergic to Pd. It has also been documented that metal ions, which are released from restorations by corrosion, can penetrate dental hard tissues (Söremark et al., 1968; Kratzenstein et al., 1986, 1988).
Analysis of the available data indicate that materials containing higher amounts of Cu, In, or Be are likely to cause tissue alterations, such as inflammation and necrosis, in particular. It may also be concluded that Ni-Cr alloys show increased corrosion in a biological environment.
Before, you place a restoration in your mouth, make sure you know what material it is! Please contact the office if you have any questions.