Local RANKL gene transfer to the periodontal tissue accelerates orthodontic tooth movement

Area of Science:

• Orthodontics
• Gene Therapy
• Periodontal Tissue Engineering

Background:

• Tooth movement (TM) involves alveolar bone resorption, influenced by receptor activator of nuclear factor kappa B ligand (RANKL).
• Pharmacological acceleration of TM typically requires frequent systemic or local administration due to rapid clearance.
• Previous studies showed OPG gene transfer inhibited TM, suggesting RANKL's role in accelerating it.

Purpose of the Study:

• To investigate the hypothesis that local RANKL gene transfer into periodontal tissue accelerates experimental tooth movement.
• To evaluate the effects of local RANKL gene transfer on RANKL expression and osteoclastogenesis during orthodontic tooth movement.

Main Methods:

• Wistar rats underwent palatal movement of upper first molars using fixed orthodontic wires.
• Inactivated hemagglutinating-virus of Japan (HVJ) envelope vector carrying mouse RANKL plasmid was periodically injected into the palatal periodontal tissue.
• RANKL expression, osteoclastogenesis, and the rate of tooth movement were assessed.

Main Results:

• Local RANKL gene transfer significantly increased RANKL expression and osteoclastogenesis in the periodontal tissue.
• No systemic effects were observed from the local gene transfer.
• A significant increase in the rate of tooth movement was observed in the RANKL gene transfer group.

Conclusions:

• Local RANKL gene transfer effectively activates osteoclastogenesis and accelerates experimental tooth movement.
• This approach holds promise for reducing orthodontic treatment duration.
• Local RANKL gene transfer may also be beneficial for moving ankylosed teeth, where bone fusion impedes movement.