Effect of temperature local dental anesthetics on injection pain

INTERVENTION: In dental student volunteers, a dentist of Dental Emergency Service will administer in two points of the maxilla: One side with a 0,9 ml anesthesia ( 2% lidocaine with epinephrine 1: 100,000) in 42°C; and opposite side 0,9 ml of the same anesthetic in room temperature (21°C). Then, a researcher will show a Visual Analogue Scale with ten points (0=none pain to 10= unbearable pain) where the patient must indicate the intensity of perceived pain in the two points previously injected. The dentist and participants will be blind about the side of the injected site and the temperature of the cartridge anesthesia. CONDITION: Perception of pain felt during dental procedures after administration of anesthesia ; Oral Health PRIMARY OUTCOME: 1. Independent Variable: 2 groups of cartridge anesthesia temperature: cartridge in 42°C and cartridge in temperature room (21°C); 2. Dependent Variable: Intensity pain level (VIsual Analogue Scale ‐ VAS) from 0 point (no pain) to 10 points (unbearable pain) INCLUSION CRITERIA: 1. Students over the age of 18 2. Given their informed consent