Related Experiment Video
Updated: Jan 28, 2026

Studying Orthodontic Tooth Movement in Mice
Published on: August 2, 2024
Osteoblast differentiation during orthodontic tooth movement
Robert Holland1, Carol Bain2, Achint Utreja3
1Indiana University School of Dentistry, Indianapolis, Indiana.
Objectives:
To analyse the expression of osteoblast differentiation markers and osteoclast activity in the periodontal ligament (PDL) following 2, 4 and 7 days of orthodontic tooth movement (OTM) in an animal model.
Setting And Sample Population:
Eighteen C57BL/6 wild-type mice.
Material And Methods:
For the OTM model, orthodontic force was applied to the maxillary right first molar using a closed-coil NiTi spring activated between the molar and incisors. The left side served as the control. Following OTM, the dissected tissues were scanned for micro-computed tomography (micro-CT) analysis and processed for histology. Histological stains included tartrate-resistant acid phosphatase (TRAP) staining for osteoclasts and immunohistochemistry for osteoblast markers alpha-smooth muscle actin (α-SMA), osteopontin (OP) and osteocalcin (OC).
Results:
Micro-CT analysis showed increasing OTM on days 2, 4 and 7 days as well as decrease in bone volume and per cent bone volume at 4 and 7 days. Statistically significant increases in osteoblast marker expression were seen in all groups when compared to the control. TRAP expression was highest at 4 and 7 days, α-SMA was highest at 2 days and OP/OC was highest at 4 days.
Conclusion:
During OTM, proliferation of pre-osteoblasts peaks at 2 days while mineralization of the osteoid peaks at 4 days. The osteoclast response is delayed.
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