Thirty patients and students are involved. All adult patients referred to the dental department for initial endodontic treatment are given the option of taking part, excluding those presenting cardiovascular disease or mental, psychiatric, or neuronal disease. Patients taking antihypertensive treatment, anxiolytics, sedatives, or neuroleptic drugs are also excluded from the study. Thirty dental students will conduct endodontic treatments according to the regular local procedures. No patient receives any sedative premedication.