Metal Hypersensitivity to TMJ Implant Materials

Hypersensitivity to TMJ implant materials is an issue that the TMJ Association frequently hears from TMJ patients. Given this concern they contacted Marco Caicedo, Ph.D., Senior Scientists and COO at Orthopedic Analysis in Chicago, IL. Orthopedic Analysis is an independent diagnostics company dedicated to the quantitative analysis of immune responses to biomaterials (i.e metal allergy to implant materials). The TMJ Association thanks Dr. Caicedo for writing this state-of-the-art article.

What is a Metal Hypersensitivity?

Metal hypersensitivity (or metal sensitivity) can be defined as an immune reaction that is triggered by specific cells of the body’s immune system in response to certain metals (like: nickel, cobalt, and chromium). While metal hypersensitivity can be considered a type of allergy, it does not induce the immediate allergy symptoms that occur when exposed to seasonal or household allergens like pollen, animal dander, mold, etc. Metal hypersensitivities have a delayed onset from the time of exposure to the materials and are not caused by specific antibodies or histamine release that lead to the classical indications of a common allergy like itching, watery eyes, or sneezing.  Metal hypersensitivity requires a first-step sensitization stage where specific cells of the immune system(T lymphocytes) recognize, activate, proliferate and form immunological memory upon contact with sensitizing agents like metals. Immunological memory occurs once the immune system is exposed for the first time to a new antigen (virus, fungus, or chemical). Once immunological memory has been formed, a secondary exposure to metal leads to all the classical inflammatory symptoms of delayed type hypersensitivity, which are described below as compared with an immediate type hypersensitivity which you would get from a food allergy or bee sting.

To learn more about this topic, read the full five page article at

Reprinted from the Volume 13 No. 1 2013 issue of Communiqué, a publication of the TMJ Association