D

Patients who react to costume jewelry are usually nickel-hypersensitive; nickel-chromium (Ni-Cr) dental alloys release nickel ions and are well-documented triggers of allergic reactions, whereas high-gold, low-gold, and Pd-Ag alloys are essentially nickel-free and generally tolerated. Therefore Ni-Cr is contraindicated in such patients [Hensten-Pettersen, 1992, PMID 1292460; Tramontana, 2020, PMID 31994473].