Evaluation of the Chemo-preventive Effect of Combined Topical and Systemic Metformin on Oral Leukoplakia

Inclusion Criteria: * Adult patients over 21 years. * Patients clinically diagnosed and histologically confirmed as having oral Leukoplakia. * Lesions with mild to moderate degree of dysplasia. * Patients who agree to sign a written consent after understanding the nature of the study. Exclusion Criteria: * Patients with lesions showing sever degree of dysplasia. * Patients who have cardiovascular, lung, Renal, Liver diseases * Patients on metformin therapy (eg: Diabetes Mellitus, PCOS, …etc.) * Patients on H2 blocker \& proton pump inhibitors therapy as Ranitidine (affects metformin absorption and clearance) * Those with allergy or sensitivity to Metformin therapy or having any contraindication for their use. * Patients on Retinoid, green tea supplements or another natural products therapy * Patients with other accompanying oral lesions * Pregnant or Lactating females