RESUMO
The Doppler ultrasonography (DU) in cases of arteriovenous malformations (AVMs) is not widely use by dentists and there are a lack of information on the topic in the literature. AVM is common in the region of the head and neck and are commonly confused with hemangiomas (congenital). Appropriate classification is essential for therapeutic decision. The diferential diagnosis is based on clinical history, diascopy, and, if necessary, diagnostic imaging. This article present two cases of oral AVM in which DU was crucial in detecting a venous and/or arterial component in purplish lesions in the tongue and buccal mucosa, with positive diascopy. In our cases, after DU, we found a predominance of blood component within the lesion and therefore both patients were referred to the head and neck surgeon for surgical removal of the lesion. Only in the presence of a venous component does outpatient treatment become feasible. Given the predominance of the arterial component, outpatient procedures are contraindicated. Therefore DU is an important supplementary test, being of great importance in the clinical decision and treatment plan for oral AVMs and should become a routine part of the dentist front of vascular lesions of medium to large size.