Osteosarcoma (OS) is a primary malignant bone tumour with a worldwide incidence of 3.4 cases per million people per year. Diagnosis of the tumour is important especially in early stages for better treatment and prognosis. These neoplasms often show typical clinical behaviour as well as varied radiological appearances. The dentists must be careful in evaluating the clinical and radiologic clues. The aim of this case presentation is to emphasize the importance of dentists on diagnosis and prognosis of oral malignancies.