Objective The purpose of this investigation was to recognize pulp sensitivity changes in teeth receiving orthodontic treatment by means of an electric pulp tester (Vitality Scanner Model 2006; Kerr Corporation, Brea CA, USA). Materials and methods An electric stimulus response threshold of eight teeth in 22 patients was measured prior to positioning orthodontic attachments, immediately before ligation of a nickel titanium archwire, immediately after ligation of a stainless steel archwire and 9 to 15 months after having achieved the clinical purposes established with the nickel titanium archwires. The first measurement served as baseline. Results All teeth responded to an electrical stimulus at all times. No statistical differences were observed between the response thresholds obtained at different treatment times. The mean response threshold of the second measurement showed a decreasing response threshold tendency when compared with those of the baseline measurement. The mean response threshold of the third measurement showed an increasing tendency when compared with those of the baseline measurement. The first maxillary incisor and canine showed the lowest decreasing response threshold after the second measurement and the highest increasing response threshold after the third measurement. Less noticeable, but similar decreasing and increasing response threshold tendencies were observed in all other teeth after the second and third measurements, respectively. Conclusions The results obtained in this investigation suggest that pulp sensitivity can be monitored during orthodontic treatment by means of an electric pulp tester. Clinical relevance The importance of monitoring the pulp status during orthodontic treatment.