At the 6 steps of the treatment and at the next visit for the final restoration, both subjects (patient and student) are asked to use a visual analog scale (VAS) to score the level of stress specifically induced by the endodontic treatment. The VAS is a 10-cm scale without graduation on which subjects are asked to score the specific level of stress experienced from 0 (not stressed at all) to 10 (worst stress imaginable). The VAS of stress has proven to be a valid tool that is highly sensitive to change.