Where do we begin? In order to understand how teeth move, we need to first visualise some basic anatomy of the teeth, gums, and jaw bones.
Our teeth have two anatomical parts; the crown (the part of the tooth that is visible above the gum line) and the root (the part embedded in the jaw bone below the gum line). Our teeth are attached to the jaw bone via a periodontal ligament. This periodontal ligament is composed of thousands of fibers anchoring the tooth to the jaw bone and acting as a shock absorber during chewing. Overlying the tooth roots and jaw bone is our gums, which is a soft tissue surrounding the tooth and providing a seal around it.
During orthodontic treatment, the teeth are aligned and any positional discrepancies or rotations are corrected. So how does this happen? Orthodontic tooth movement is dependent on the remodelling* and turnover of the jawbone. When a tooth is pushed in a certain direction, the periodontal ligament on one side of the tooth is squeezed against the jawbone (compression) while the periodontal ligament on the other side of the tooth is stretched (tension). This pressure change in the periodontal ligament alters the blood flow and distorts the adjacent fibres and cells. This trigger activates a cascade of cellular and biochemical events in the jawbone, resulting in i) bony remodeling, and ii) subsequent tooth movement.
Orthodontic tooth movement occurs by applying a light, optimal force for a sufficient duration to a tooth. A healthy periodontal ligament and gums is essential for orthodontic tooth movement. This is one of the reasons why good oral hygiene and regular general dental checkups is so important during your orthodontic treatment.
* Throughout life our skeleton is continuously remodeled by different bone cells. This occurs as a coupled process in which the skeleton is renewed while maintaining its structural integrity.