Biology of Orthodontic Tooth Movement

Prolonged Tooth Pressure Movement

• Tooth movement involves the remodelling of the tooth socket, crucial for orthodontic treatment.
• Bone remodelling occurs around the periodontal ligament, entailing both apposition (building) and resorption (loss) of bone.
• The periodontal ligament undergoes reorganisation during tooth movement.

Stimuli for Bone Remodelling

• Changes in blood flow to the periodontal ligament (PDL) serve as a key stimulus for bone remodelling.
• The piezo-electric effect, potentially tied to biological electricity, may also play a role in this process.

The Piezo-Electric Effect

• The piezo-electric effect refers to the generation of an electrical current when crystalline materials, such as bone, change shape under stress.
• This effect is significant in skeletal tissues, potentially influencing bone remodelling and health.

Piezo-Electricity in Bone

• Sources of piezo-electricity in bone include bone minerals and collagen.
• Mechanical activities like chewing and walking generate rhythmic electric pulses that help maintain bone mineralisation.

Time Course of Events Under Heavy Biting Pressure

• Initial response to heavy biting pressure occurs within milliseconds, characterized by the incompressibility of fluid in the periodontal ligament.
• Over seconds, fluid leaks out of the periodontal ligament, facilitating movement and remodelling processes.