A longitudinal evaluation of pulpal pain during orthodontic tooth movement

Objectives – To examine the longitudinal changes in pulpal sensitivity to electrical stimulation and the relationship to pulpal sensitivity as measured by electrical stimulation and subjective reports of tooth pain after archwire insertion. Design – Non‐randomized, prospective trial, with matched controls. Setting and Sample Population – Regional Clinical Dental Research Center at the University of Washington School of Dentistry. Eighteen adult subjects of age 13–37 years. Nine experimental subjects planned for orthodontic treatment. Nine control subjects matched for gender and age who did not have orthodontic treatment. Experimental Variable – Fixed orthodontic appliances and initial archwire placement in experimental subjects compared with `no treatment' control subjects. Outcome Measure – Subjective assessments of orthodontic tooth pain were made using visual analogue scales. Electrically evoked detection and pain thresholds were determined using a computer‐controlled tooth stimulator. Data were gathered at five time points: after bracket placement (baseline), 1 h after placement of initial archwires, 1 day after archwire placement, 1 week after archwire placement, and 1 month after archwire placement. Comparable time intervals were used for the `no treatment' control subjects. Results – Subjective ratings of treatment‐evoked tooth pain in the experimental group were the greatest at the post‐archwire day 1 observation and progressively decreased for the remaining observations. Control subjects reported little pain at any of these observation times. The detection and pain threshold changes from baseline showed no statistical differences over time or between groups. While not statistically significant, a trend was noted where reports of greater orthodontic tooth pain were associated with increased sensitivity to electrical stimulation (i.e. lower detection and pain thresholds). Conclusion – Orthodontic patients experience significant pain and discomfort 1 day after initial archwire placement (i.e. activation). Future research should investigate whether self‐reports of treatment‐evoked tooth pain intensity are associated with pulpal sensitivity.