Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Objectives. The aim of this study was to evaluate the possible toxic effects of articaine and lidocaine on mental nerve, due to the increasing number of paresthesia cases after nerve blocks. Materials and methods. The drugs were injected in the anterior portion of mental nerve of 24 rats, divided into three groups: G1-4% articaine with 1: 100,000 epinephrine; G2-2% lidocaine with 1: 100,000 epinephrine and G3-plain 1: 100,000 epinephrine solution. These solutions were injected in the right side of the rat's mandible and the left side was used as control (0.9% saline solution). Previously to the injections, the animals were anesthetized with thiopental and, 24 h after the injections, their jaws were removed and submitted to routine histological techniques. A histopathological analysis was performed by optical microscopy. Results. An inflammatory infiltration was found around mental nerve, classified as intense for G3, moderate for G1 and light for both G2 and control groups. No injuries were found in nervous structure, despite the inflammatory reaction observed around it. Conclusion. The results suggest that articaine is not toxic to the nervous structure and further studies are necessary to explain the possible relation between articaine injection and paresthesia.7118287Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)