PIXE analysis of trace elements included in oral lichen planus-affected mucosa

The purpose of our research is to identify causative metals by using particle-induced X-ray emission (PIXE) method to directly analyze trace elements in the oral mucosa with oral lichen planus (OLP). Subjects were 72 patients with OLP, and the patients are 25 men and 47 women, with a mean age of 60.1 years (OLP group). The control is elemental analysis data by PIXE method of 100 cases of the oral mucosa of healthy persons (control group). Seventeen essential elements and 12 contaminating elements were detected from the oral mucosa of the OLP and control groups. As to appearance ratio of elements in oral mucosa, among the contaminating elements, levels of Al, Ga, Sb, Hg and Pb were significantly lower, whereas Au and Y were significantly higher in the OLP group than in the control group. About concentration of elements in oral mucosa, the contaminating elements in the oral mucosa of the OLP group had a lower appearance ratio than in the control but each of the contaminating elements was more abundant. Among 25 subjects in the OLP group and seven in the control group, serum, oral mucosa and saliva were collected from the same individual. Abundance in serum and saliva varied depending on the element, but in general, a tendency was seen for contaminating elements to be more abundant in saliva than in serum and for essential elements to be more abundant in serum than in saliva.