The aim of this study was to verify the effectiveness of an anesthetic called articaine for dental treatment, comparing it with an anesthetic commonly used in dental clinic: lidocaine. Two types of local anesthesia (oral injection) in accordance with the solution used were performed. For patients anesthetized with articaine, an injection of anesthesia close to the tooth to be treated was used. For the anesthetic lidocaine an injection on the cheek at the bottom of the mouth was made. Differences between both techniques are mainly regarding the area of numbness. In the injection with articaine only a small part of the lip and the tooth was anesthetized. With lidocaine injection, the lower region of the entire side of the tooth and half of the tongue on the same side was numbed. The treatment was electronic randomized and there was equal chance to one or another treatment. The investigators are studying this new form of anesthesia (near the tooth that was treated) to see if it can numb the tooth to an emergency treatment, if it really decreases the feeling of numbness and discomfort during the service. Patients receiving articaine were submitted to cone beam exam at no cost.