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Updated: Jan 25, 2026

3D Imaging of PDL Collagen Fibers during Orthodontic Tooth Movement in Mandibular Murine Model
Published on: April 15, 2021
Differences in accelerated tooth movement promoted by recombinant human parathyroid hormone after mandibular ramus
Yao Li1, Xiao-Yan Chen1, Zheng-Long Tang1
1Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Guizhou Medical University, Guiyang, People's Republic of China.
Introduction:
This study investigated the effects of different doses of parathyroid hormone (PTH) on orthodontic tooth movement after mandibular ramus osteotomy and the associated dose-response relationship.
Methods:
One-hundred twenty rabbits were divided into 2 experimental groups (A and B) and 2 control groups (control group and negative control group). An experimental model of mandibular ramus osteotomy with installation of an orthodontic tooth movement device was established in groups A and B and the control group. After surgery, groups A and B received intermittent subcutaneous injections of PTH, 20 and 40 μg/kg, respectively, and the control group received injections of normal saline solution. The negative control group underwent installation of the orthodontic tooth movement device without mandibular ramus osteotomy and received normal saline solution after surgery. Changes in expression of RANKL and RUNX2 in the periodontal tissues of the first molars were evaluated by means of immunohistochemical analysis and quantitative fluorescence polymerase chain reaction.
Results:
Movement of the first molars was more rapid in group B than in group A in the 21 days after surgery. Significantly higher RANKL mRNA levels and lower RUNX2 mRNA levels were detected on the compression side of the periodontal tissues in groups A and B than in the control groups. There was a significant difference in RANKL and RUNX2 expression levels between group B and the control groups at all time points.
Conclusions:
Mandibular ramus osteotomy combined with high-dose PTH can increase catabolism on the compressed periodontal tissues, thereby accelerating remodeling of periodontal bone and promoting orthodontic tooth movement after surgery.
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