Most people assume braces pull teeth into line, like tightening a rope. What actually happens is more interesting, and it explains why orthodontic treatment takes months rather than weeks — and why forcing it faster does not work.
Teeth are not fixed in bone
Each tooth sits in a socket, suspended by a network of fibres called the periodontal ligament. That ligament is a living, responsive tissue. It is what lets you feel a grain of sand between your teeth.
Because a tooth is suspended rather than fused, it can be moved — if you apply the right kind of force.
Bone remodelling: the actual mechanism
When a wire applies gentle continuous pressure to a tooth, the ligament on the pressure side is compressed and the side being pulled is stretched.
The body responds. On the compressed side, cells called osteoclasts dissolve bone, clearing a path. On the tension side, osteoblasts lay down new bone, filling in behind. The tooth migrates through the jaw, and the bone rebuilds around its new position.
This is remodelling, not stretching. It is the same biological process that heals a fracture, directed deliberately.
Why gentle force works better than strong force
This is the counterintuitive part. Heavy pressure does not move teeth faster — it moves them slower, and it causes damage.
Excessive force crushes the ligament and cuts off its blood supply, which stalls the remodelling process entirely. Sustained heavy force can also cause root resorption, where the root tip is shortened permanently.
So the wires used are light and flexible at the start of treatment, becoming heavier and more rigid only in the later stages when the teeth are already aligned and the fine detail is being set.
Why you feel it for a few days
After each adjustment the ligament is compressed and inflamed, which is what makes the teeth feel tender when you bite. It settles in one to three days as the remodelling gets under way. Managing that discomfort is covered separately.
Teeth also feel slightly loose during treatment. That is expected — the ligament is widened while the tooth is moving. Bone tightens around it again once movement stops.
The parts of a fixed appliance
- Brackets — bonded to each tooth, they transfer force from the wire to the tooth
- Archwire — the engine. It is shaped to the ideal arch form and tries to return to that shape, dragging the teeth with it
- Ligatures — elastic or metal ties holding the wire in the bracket slot
- Bands — metal rings around back molars for anchorage
- Elastics — worn between upper and lower jaws to correct the bite. These depend entirely on the patient wearing them
Why treatment takes 12 to 24 months
Bone remodelling has a biological speed limit — roughly a millimetre a month under ideal conditions. No appliance, technique or advertisement changes that limit. Anyone promising straight teeth in weeks is either doing something superficial like veneers, or overloading the teeth.
And why retainers are not optional
When braces come off, the bone around the teeth is still reorganising and the ligament fibres remain stretched, pulling toward the original position. That reorganisation takes months.
Retainers hold the teeth still while it completes. Without them, relapse is not a risk — it is close to a certainty.
Read more about the types of braces available, or see our braces and clear aligners page. Call 8359017239 for an assessment.
