[Several non-traumatic examination methods for oral leukoplakia lichen planus and carcinoma].

For early diagnosis of malignant changes, in oral leukoplakia and lichen planus based upon the experience of experimental study we did before, several non-traumatic examination methods were used in clinical cases. Results showed that the accurate rates of toluidine blue staining and hematoporphyrin derivative (HpD) local application are 90 percent. Transmission electron microscopic study of cytology indicates that cellular ultrastructures are different distinctly between cells of the malignant tissue and normal mucous membrane or leukoplakia with simple hyperplasia.