title: The Effect of Orthodontic Forces on Tooth Response to Electric Pulp Test.
abstract: The current study investigated the pulp response to electric pulp testing (EPT), before, upon initiation and one month after the start of orthodontic tooth movement.
  
  
  
  A total of 402 anterior teeth from 39 patients (mean age of 16.8±2.7 years) were examined in this non-controlled prospective study. The aligning forces were administered using initial NiTi archwires ligated on fixed appliances by using the MBT straight wire technique. The electrical stimulation was provided by the EPT. The EPT readings were recorded at three time points: before bonding (EPT0), immediately upon initiation (EPT1) and 1 month post-treatment (EPT2). The data were statistically analyzed by the ANOVA and Bonferroni tests (P<0.05).
  
  
  
  Prior to bonding of the orthodontic brackets, the mean EPT value for all the experimental teeth was 3.42 EPT units. Upon initiation, the mean value of EPT1 for each tooth increased to 7.62 units. One month later, the mean EPT2 values dropped to 6.27 units. At this time point, 64 teeth (16%) of the experimental teeth failed to respond. The differences among EPT values at different time points were significant. There was no association between the EPT values and the location or the type of teeth.
  
  
  
  The physiological changes in the pulp affect the nerve fibers in the early stages of the orthodontic force application. As a result, thresholds to electrical stimulation would increase and the EPT may not initiate a response. Therefore results obtained by electrical pulp testing should be interpreted accordingly.
authors.affiliation: Department of Endodontics, Dental School, Social Determinants of Oral Health Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran;
authors.forename: Jalil
authors.initials: J
authors.lastname: Modaresi
authors.affiliation: Department of Orthodontics, Dental School, Shahid Sadoughi University of Medical Sciences, Yazd, Iran ;
authors.forename: Hosein
authors.initials: H
authors.lastname: Aghili
authors.affiliation: Iranian Center for Endodontic Research, Research Institute for Dental Sciences, Department of Endodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran ;
authors.forename: Omid
authors.initials: O
authors.lastname: Dianat
authors.affiliation: Dentofacial Deformities Research Center, Research Institute for Dental Sciences, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran ;
authors.forename: Farnaz
authors.initials: F
authors.lastname: Younessian
authors.affiliation: Department of Molecular and Cell Biology, Henry M. Goldman, Medical School, Boston University, Boston, MA, USA.
authors.forename: Faranak
authors.initials: F
authors.lastname: Mahjour
keywords: Electric Pulp Test; Orthodontic Treatment; Pulp Vitality