Trace metals in oral mucosa in relation to the lichen ruber planus pathology. A preliminary study carried out by neutron activation analysis

Lichen ruber planus, contact allergy and hypersensitivity can be linked to oral exposure to metals released from metal alloys commonly used in dentistry. In this context neutron activation analysis was developed for the microdetermination of 36 elements in oral mucosa biopsies of two patients affected by lichen ruber planus and of five subjects as control group. In order to minimise metal contamination during sample collection, biopsies were taken by Laser bistoury technique and then submitted to radiochemical neutron activation analysis (RNAA). Among the metals analysed, chromium showed obvious high concentration in gingival biopsies of the two pathological subjects compared to the corresponding tissues of control group. Cobalt and nickel were also determined in higher concentrations, but only in one of the oral mucosa of the two patients. The present findings way support the hypothesis concerning a potential link of lichen ruber planus condition with the exposure to Cr, Co and Ni as released into oral cavity from prosthodontic alloys.