---
title: "How Orthodontics Works: Braces and Aligners"
url: https://virtualconsultant.online/guides/how-orthodontics-works-uk
description: "Braces and aligners move teeth by applying gentle sustained force that makes the bone around each root remodel gradually into a new, straighter position."
updated: 2026-08-17T00:00:00Z
publisher: Virtual Consultant Online
---

Biomechanics

Braces

Aligners

# How Orthodontics Works UK

Orthodontics moves teeth by applying controlled, sustained force so that the ligament and bone around each tooth root remodel gradually, allowing the tooth to shift into a new position over weeks and months. Braces and aligners achieve this the same biological way but through different mechanical systems — fixed wires and brackets versus a staged series of custom plastic trays.

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## How do teeth actually move?

Each tooth sits in a socket of bone, held in place by a periodontal ligament wrapped around its root. When a gentle, sustained force is applied to a tooth — from a wire, a bracket, or an aligner tray — that ligament is compressed on one side and stretched on the other. This triggers a biological remodelling response: bone-dissolving cells (osteoclasts) clear space on the compressed side while bone-building cells (osteoblasts) lay down new bone on the stretched side. Over days and weeks, the tooth physically migrates through the bone into a new position, with the ligament and surrounding bone rebuilding around it at every stage.

## How do fixed braces move teeth?

Fixed braces work by bonding a small bracket to each tooth and threading a shaped archwire through them. The archwire is manufactured with a memory for its ideal shape, so when it is engaged into the brackets on crooked teeth, it constantly applies a gentle spring-like force trying to return to that shape — pulling the teeth with it. Orthodontists change wires through treatment, starting with thin, flexible wires for initial alignment and progressing to thicker, stiffer wires for bite correction and fine detailing. Elastics and additional components add specific forces for movements the wire alone cannot achieve.

## How do clear aligners move teeth?

Clear aligners move teeth through a pre-planned series of small incremental steps, with each tray in the series nudging the teeth slightly closer to their final position. Small tooth-coloured attachments bonded to certain teeth act as grip points so the smooth plastic tray can apply more precise or complex forces, and elastics may be added for bite correction. Because each tray only makes a very small movement, aligners rely on wearing each one for the prescribed number of hours daily and progressing through the sequence on schedule; missed wear time means the tray no longer matches the tooth position, causing poor tracking.

## Why can't orthodontic treatment be sped up indefinitely?

Biology sets a hard limit on how fast teeth can safely move, because bone remodelling is a living cellular process that takes time regardless of how much force is applied. Using excessive force does not accelerate the process — instead it can cut off blood supply to the ligament, increase the risk of root resorption (permanent shortening of the tooth root), cause more pain and swelling, and in aligner treatment, cause trays to stop fitting properly because the tooth cannot keep pace with the plan. Safe, moderate, sustained force applied consistently is what produces reliable, lasting results.

## Why do teeth need retainers after treatment?

When active treatment ends, the bone and ligament around each tooth have only just finished remodelling into the new position and have not yet fully matured or stabilised. Without a retainer holding teeth in place during this consolidation period, the same biological forces that allowed movement during treatment allow teeth to drift back towards their original position, a process called relapse. Retainers — whether a fixed wire bonded behind the teeth or a removable clear tray — apply just enough passive resistance to keep teeth still while the surrounding bone fully consolidates, which is why long-term or indefinite retainer wear is recommended.

## Useful related pages

[How Braces Work UK](https://virtualconsultant.online/guides/how-braces-work-uk)

[Orthodontic Wire Types UK](https://virtualconsultant.online/guides/orthodontic-wire-types-uk)

[Clear Aligner Attachments UK](https://virtualconsultant.online/guides/clear-aligner-attachments-uk)

[How to Speed Up Braces UK](https://virtualconsultant.online/guides/how-to-speed-up-braces-uk)

This guide is for general information only. It is not a diagnosis, treatment plan, or substitute for advice from a registered dentist or orthodontist.

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### Frequently Asked Questions

Do braces move teeth through bone?

Braces move teeth by triggering controlled remodelling of the bone that surrounds each tooth's root, rather than forcing the tooth through solid, unchanged bone. Sustained gentle pressure from the archwire causes bone-dissolving cells to clear space on one side of the tooth while bone-building cells add new bone on the other side, allowing the tooth to physically migrate into its new position as the surrounding bone continually rebuilds around it.

Are aligners weaker than braces?

Aligners are not simply weaker than braces; the two systems are better suited to different types of movement. Aligners are highly effective for many alignment, crowding, and spacing cases, while fixed braces can be more predictable for complex movements like large rotations, root positioning, or significant bite correction. Which option is right for a given patient depends on an accurate diagnosis of the specific tooth movements required, not on general claims about which appliance is stronger.

Can orthodontic treatment damage tooth roots?

Some degree of root shortening, known as root resorption, can occur in a minority of orthodontic patients, particularly with prolonged treatment, heavy forces, or certain root shapes that are more susceptible. Orthodontists monitor this risk using periodic X-rays during longer treatment courses and adjust force levels if early signs are detected. In most patients, any resorption that occurs is minor and does not affect the long-term health or function of the tooth.

How much force is used to move teeth?

Orthodontic tooth movement uses very light, biologically appropriate forces, typically in the range of 15 to 60 grams for tipping movements and higher for more complex movements like torque or intrusion. This is far gentler than most patients expect — the sensation of pressure after an adjustment comes from the ligament responding to sustained load, not from a strong physical force. Using more force than necessary does not move teeth faster and increases the risk of root resorption and discomfort.

Why does tooth movement feel uncomfortable for a few days after an adjustment?

When a new wire is engaged or a new aligner tray is fitted, the ligament around each affected tooth experiences a fresh wave of compression and tension as the remodelling process restarts. This triggers mild inflammation, which is what produces the dull ache or tenderness felt for two to four days after an adjustment or when starting a new aligner. The discomfort settles as the bone and ligament adapt to the new force, which is why soreness is usually worst in the first day or two after each change and fades steadily afterwards.

What is anchorage and why does it matter?

Anchorage is what resists the force you apply. Every force used to move a tooth pushes back equally on whatever it is braced against, so pulling a front tooth backwards also tends to drag the back teeth forwards. Managing that is much of the craft of orthodontics. It is controlled by grouping teeth together, by elastics worn between the arches, by palatal or lingual arches, and increasingly by small temporary anchorage devices placed in the bone, which do not move at all. Poor anchorage control is a common reason a case finishes with space closed from the wrong end.

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Quick links

Not sure where to start? Use these quick links to explore orthodontic treatments, typical costs, and helpful guides that explain what different options involve. Whether you're researching braces or clear aligners, comparing pricing, or just getting a feel for what comes next, you can browse at your own pace and come back when you're ready to request a quote.

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[How To Take Orthodontic Photos](https://virtualconsultant.online/about/process/how-to-take-orthodontic-photos)

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Citation details

Title How Orthodontics Works: Braces and Aligners

Publisher Virtual Consultant Online

Published 2024-06-01

Updated 2026-08-17

URL [https://staging.virtualconsultant.online/guides/how-orthodontics-works-uk](https://staging.virtualconsultant.online/guides/how-orthodontics-works-uk)