title: Change in dental pulp parameters in response to different modes of orthodontic force application.
abstract: OBJECTIVE
  (1) To evaluate dental pulp sensitivity by electrical pulp testing and measure aspartate aminotransferase activity in the pulp after 14 days of orthodontic intrusion, and (2) to compare those measurements with measurements obtained in teeth after 7 days of intrusion and 7 days of rest.
  
  
  METHODS
  The study sample included 13 subjects (mean age = 16.5 +/- 2.7 years). For every subject, before extraction, two contralateral premolars were included in a spring and loaded by a force. Two study groups were formed: Group A, teeth with 14 days of mechanical load, and Group B, teeth with 7 days of mechanical load plus 7 days of rest. Electrical pulp testing and aspartate aminotransferase activity measurements were performed after 14 days in all tested teeth. After extraction, aspartate aminotransferase activity in the pulp was determined spectrophotometrically at 20 degrees C.
  
  
  RESULTS
  Mean aspartate aminotransferase activity values were 0.21 U/mg (SD = 0.15) in Group A and 0.27 U/mg (SD = 0.17) in Group B. Mean electrical pulp testing readings were 38.92 microA (SD = 24.61) in Group A and 36.77 microA (SD = 26.84) in Group B. Mean values of the intrusive force magnitude did not differ in both groups.
  
  
  CONCLUSIONS
  Different durations of orthodontic intrusion, defined as 14 days of load and 7 days of load followed by 7 resting days, were not reflected by electrical pulp testing or by aspartate aminotransferase activity levels in the pulp of the affected teeth. However, the response threshold to electrical pulp stimulation was elevated in all tested teeth.
authors.affiliation: Clinic of Dental and Oral Pathology, Kaunas University of Medicine, Kaunas, Lithuania. r.veberiene@gmail.com
authors.forename: Rita
authors.initials: R
authors.lastname: Veberiene
authors.forename: Dalia
authors.initials: D
authors.lastname: Smailiene
authors.forename: Nomeda
authors.initials: N
authors.lastname: Baseviciene
authors.forename: Adolfas
authors.initials: A
authors.lastname: Toleikis
authors.forename: Vita
authors.initials: V
authors.lastname: Machiulskiene
mesh_terms: D000293:Adolescent; D001219:Aspartate Aminotransferases / Q000378:metabolism; D003782:Dental Pulp / Q000378:metabolism*; D003791:Dental Pulp Test; D003799:Dental Stress Analysis; D003807:Dentin Sensitivity / Q000209:etiology*; D006801:Humans; D013314:Stress, Mechanical; D013997:Time Factors; D014087:Tooth Movement Techniques / Q000009:adverse effects; D055815:Young Adult
chemical_list: D001219:Aspartate Aminotransferases