Typical length by case
| Case | Typical length |
|---|---|
| Minor crowding or a small gap in the front teeth | About 3–6 months |
| Moderate crowding or spacing | About 6–12 months |
| Bite correction (overbite, underbite, crossbite) | About 12–18 months or more |
| Relapse after braces years ago | Often 3–9 months |
These are ranges, not promises. Your own estimate comes from the 3D plan.
Stage by stage
Week 0: assessment. Our orthodontist examines your teeth, gums and bite, and takes X-rays, photographs and a 3D scan. Any decay or gum disease is treated first.
Weeks 1–3: your plan. You see the planned movement on screen, agree it, and get a written plan with the number of aligners, the timeline and the fee.
First aligner appointment. Small tooth-coloured attachments may be bonded to some teeth. You get your first sets and learn how to put them in, take them out and clean them. The first few days feel tight; this settles.
Every 1–2 weeks: a new set. Each set moves the teeth a little further. Keep your previous set in case one is lost.
Every 6–10 weeks: check-up. The orthodontist checks that the teeth are tracking the plan and gives you the next sets. Sometimes a little smoothing between teeth or elastics are added.
Near the end: refinements. Most people need a few extra aligners to fine-tune the final position. A new scan is taken and the refinement sets are made.
Finish: retainers. Attachments are polished off and retainers are fitted, removable, fixed behind the front teeth, or both.
What keeps treatment on time
- Wear your aligners 20–22 hours a day.
- Change sets on schedule, not early.
- Keep your check-ups.
- Take aligners out for anything but plain water, and brush before putting them back.
- Tell us quickly if an aligner stops fitting or breaks.
Start with an assessment
Book an orthodontic assessment at Petal Smiles, Sector 49. You’ll know how long your treatment is likely to take, and what it costs, before you commit. Read more about Invisalign and clear aligners.
Questions patients ask us
How long does Invisalign take?
Usually six to eighteen months. Minor crowding or a small gap can take a few months; complex bites can take longer. Your orthodontist gives you an estimate after the 3D plan.
How many hours a day do I need to wear Invisalign?
20 to 22 hours. Every hour out adds up, and wearing them less is the commonest reason treatment takes longer than planned.
How often do I change aligners?
Usually every one to two weeks, as your orthodontist advises.
How many aligners will I need?
It depends on how far the teeth need to move. Short courses use a small number of sets; comprehensive treatment uses many more. Your plan shows the number.
When will I see a difference?
Many people notice changes within the first couple of months, especially with gaps and crowded front teeth.
How long do I wear retainers after Invisalign?
Full-time briefly if advised, then at night, ideally long term. Teeth can drift at any age, so retainers are what keep the result.
Sources
NHS: braces and aligners ↗Last updated 14 October 2026.