The circadian expression of osteogenic factors in periodontal tissue loading mechanical force: new concepts of the personalized orthodontic care

Xu Qin, Qilin Li, Weimin Chen, Yumin Bai, Babak Baban, Jing Mao

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Objective: The need for orthodontic treatment continues to increase. Strategies that shorten the treatment course and reduce discomfort are most welcome in clinic. Circadian rhythm plays important role in various physiological processes, including bone formation. This study intended to depict a possible circadian releasing property of the osteogenic factors within the periodontal tissue during orthodontic treatment, which may direct a more efficient and satisfactory orthodontic treatment to the patient. Methods: Primary periodontal ligament cells (PDLCs) were obtained from the Sprague-Dawley (SD) rats. An equibiaxial strain value of 12% was applied on rat PDLCs (rPDLCs). After 2 h stimuli of 10−7 M dexamethasone (DX), the osteogenic genes’ expressions were detected by real-time polymerase chain reaction (RT-PCR) at Zeitgeber times 0, 4, 8, 12, 16, 20, and 24. An orthodontic appliance was placed on 45 SD rats. Animals were maintained under 12-h light/dark periods and euthanized at 9 time points over the diurnal cycle. The orthodontic sensitive tissues of the mesial root of the maxillary first molar were collected for RT-PCR and immunohistological assay. Results: The rPDLCs displayed typical fibroblastic spindle shape, and subcultured steadily in vitro. Induced by DX, the mRNA expression of Col-1, OPN, and IBSP within the loaded/unloaded rPDLCs oscillated as that of the main clock gene Per-1. The osteogenic genes’ expressions as well as the protein releases sustained a circadian oscillation trend in vivo. Conclusions: This study indicates the existence of a circadian rhythm of the osteogenic factors within the orthodontic sensitive tissues, which highlights the importance of precise timing of force loading in further orthodontic treatment. Thus, a periodicity pattern of orthodontic traction at night may prove a more efficient tooth movement while minimizing the treatment window and discomfort complains.

Original languageEnglish (US)
Pages (from-to)13-20
Number of pages8
JournalEPMA Journal
Issue number1
StatePublished - Mar 1 2019


  • Animal model
  • Animal study
  • Biomarker panel
  • Circadian rhythm
  • Expression pattern
  • Mechanical force
  • Orthodontic tooth movement
  • Osteogenesis
  • Personalized orthodonic care
  • Predictive preventive personalised medicine
  • Prognosis

ASJC Scopus subject areas

  • Drug Discovery
  • Health Policy
  • Biochemistry, medical


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