title: Long term effect of low intensity pulsed ultrasound on a human tooth slice organ culture.
abstract: OBJECTIVE
  Investigate the effect of therapeutic Low Intensity Pulsed Ultrasound (LIPUS) on human dentine-pulp complex in an in vitro model.
  
  
  METHODS
  92 premolars were extracted from 23 adolescent orthodontic patients. The premolars were sectioned transversely into 600 μm thick slices. The slices were divided into two main groups according to how often the LIPUS was applied (single or daily application), and then subdivided into five subgroups each (5, 10, 15 and 20 min and one control group). The tooth slices were cultured at (37 °C/5% CO(2)) in a humidified incubator where medium was changed every 48 h. LIPUS was applied using a 3.9 cm(2) transducer that produces an incident intensity of 30 mW/cm(2). After five days, tissue was harvested for histomorphometrical analysis and real time PCR to investigate expression of genes of interest (Collagen I, DMP1, DSPP, TGF-β1, RANKL and OPG).
  
  
  RESULTS
  Histomorphometric analyses revealed that odontoblast cell count was higher in the single application groups (5, 10 and 15 min, respectively) than in the control and other treatment groups. Predentin thickness was higher in the single application group (10, 5 and 15 min) respectively than in the daily application group and the control groups, however they were not significantly different from each other. Real time PCR demonstrated no statistically significant difference between the groups in the expression of Collagen I, DMP1, TGF-β1, DSPP, RANKL and OPG.
  
  
  CONCLUSIONS
  Reproducible responses from cultured dentine-pulp complex were observed in groups with single application of LIPUS for 5, 10 and 15 min.
authors.affiliation: University of Alberta, Department of Dentistry, Faculty of Medicine and Dentistry, Room 4051, Dentistry/Pharmacy Centre, Edmonton, AB Canada T6G 2N8. aldaghre@ualberta.ca
authors.forename: Saleh
authors.initials: S
authors.lastname: Al-Daghreer
authors.forename: Michael
authors.initials: M
authors.lastname: Doschak
authors.forename: Alastair J
authors.initials: AJ
authors.lastname: Sloan
authors.forename: Paul W
authors.initials: PW
authors.lastname: Major
authors.forename: Giseon
authors.initials: G
authors.lastname: Heo
authors.forename: Cristian
authors.initials: C
authors.lastname: Scurtescu
authors.forename: Ying Y
authors.initials: YY
authors.lastname: Tsui
authors.forename: Tarek
authors.initials: T
authors.lastname: El-Bialy
mesh_terms: D000293:Adolescent; D001641:Bicuspid / Q000033:anatomy & histology*; D015415:Biomarkers / Q000032:analysis; D003782:Dental Pulp / Q000254:growth & development*; D003804:Dentin / Q000254:growth & development*; D005260:Female; D006801:Humans; D008297:Male; D009804:Odontoblasts; D009924:Organ Culture Techniques; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D014464:Ultrasonic Therapy
chemical_list: D015415:Biomarkers