An experimental model to demonstrate the carcinogenic action of oral chronic traumatic ulcer

Background: Oral chronic traumatic ulcer (CTU) is caused by constant irritation by dental edges or restorations and could behave as a pre-malignant lesion in a field initiated by carcinogens such as tobacco or alcohol. Methods: We developed an experimental model in the hamster cheek pouch, combining the chemical carcinogen 7,12-dimethyl-benzanthracene (DMBA) with CTU. Results: The successive or simultaneous action of both agents induced a significantly larger number of endophytic carcinomas than larger doses of DMBA alone. CTU alone failed to induce tumor development. Ploidy analysis revealed significantly higher malignancy indices in endophytic than in exophytic carcinomas. 5-Bromo-2-deoxyuridine labeling evidenced greater proliferation around the ulcers in chemically cancerized epithelium than around ulcers in healthy epithelium. Conclusions: The results show that CTU acts as a tumor promoter in this model. This finding is clinically relevant in that CTU may increase the risk of malignant transformation in patients with subclinical tumor initiation.