title: Primary dysmenorrhea is potentially predictive for initial orthodontic pain in female patients.
abstract: OBJECTIVE
  To investigate the relationship between primary dysmenorrhea (PD) and orthodontic pain in female patients, and to test the hypothesis that the intensity and duration of orthodontic pain could be roughly predicted by severity of PD.
  
  
  METHODS
  One hundred twenty college females were enrolled and put into one of three groups-mild (Mi), moderate (Mo), or severe (S)-according to level of menstrual pain. Intensity of the orthodontic pain was measured by visual analog scale (VAS) on days 1, 2, 4, 7, 14, and 28 after archwire placement.
  
  
  RESULTS
  As the intensity of orthodontic pain declined with time, the three groups demonstrated different changes during the initial week. Mi had the lowest VAS scores, whereas S possessed the highest scores. In contrast, Mo stayed in between. Significantly positive correlations were found between the severity of PD and the intensity of orthodontic pain at each time point within the first 2 weeks. In addition, though the majority of subjects reported disappearance of pain by the end of the second week in both Mi and Mo, a large proportion of females still perceived pain in S.
  
  
  CONCLUSIONS
  Females with higher levels of menstrual pain tended to perceive orthodontic pain with higher intensity and more prolonged duration. Thus, PD could potentially serve as a reference to predict orthodontic pain in clinical settings.
authors.affiliation: a  Research Assistant, State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Ye
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
authors.forename: Ruixian
authors.initials: R
authors.lastname: Wu
authors.forename: Jiao
authors.initials: J
authors.lastname: Pei
authors.forename: Jue
authors.initials: J
authors.lastname: Wang
authors.forename: Zhihe
authors.initials: Z
authors.lastname: Zhao
mesh_terms: D003080:Cold Temperature; D004412:Dysmenorrhea / Q000145:classification*; D005260:Female; D005544:Forecasting; D006801:Humans; D009967:Orthodontic Appliances / Q000009:adverse effects*; D010147:Pain Measurement / Q000379:methods*; D058748:Pain Perception / Q000502:physiology; D017288:Pain Threshold / Q000502:physiology; D013997:Time Factors; D064232:Visual Analog Scale; D055815:Young Adult