How Long Does Clear Aligner Treatment Take? How Many Months?

How many months does clear aligner treatment take?

For most patients, clear aligner treatment takes between 6 and 24 months. Mild crowding, small gaps and minor shifting after braces usually resolve in 6–9 months. Moderate crowding, noticeable gaps and mild bite problems need 12–18 months. Complex cases that combine several problems, or in which teeth need to be rotated or moved a long distance, can take 18–24 months and sometimes longer. These ranges are generally accepted figures; how many months your own treatment will take can only be told by your orthodontist after an examination and digital planning.

This time does not include the retention (retainer) phase. Once active treatment ends, a retainer is worn for a long time to keep the teeth in their new position; we cover this on our retainers after clear aligners page.

What factors determine treatment time?

How far the teeth need to move

Each aligner moves a tooth by about 0.2–0.3 millimeters. If a tooth needs to shift 3 millimeters, that means at least 10–15 aligners. Rotating teeth (especially canines and premolars), pulling them out or pushing them in vertically, and root movements are the slowest movements; plans that include them take longer. Plans that only correct slight tipping are short.

Number of aligners and how often they are changed

The planning software divides tooth movement into steps; each step is one aligner. A series of 20 aligners takes about 5 months with 7-day changes and about 10 months with 14-day changes. The orthodontist decides the change interval: 7, 10 or 14 days are chosen depending on the attachments and the type of movement. Changing more often is not always better; the tooth and the surrounding bone need time to adapt to the new position. Switching to the next aligner earlier than your orthodontist advises does not speed up treatment; on the contrary, it can cause the aligners not to fit and make treatment longer.

Daily wear time

Wearing your aligners 20–22 hours a day is the basic condition for the plan to progress on schedule. Wearing them a few hours less every day causes the teeth to fall behind the plan. When this happens the aligner no longer fits, and the orthodontist has you wear the same aligner longer or makes a new plan. Wearing habits are explained in detail on our how to wear clear aligners page.

Refinement series

When the first series of aligners is finished, the teeth are often very close to the goal but not quite there. The orthodontist takes a new digital scan and an additional series of aligners is made for fine-tuning. This series usually consists of a few aligners and adds 1–4 months to treatment. Refinement is common in moderate and complex cases; it is usually included in the time estimated at the start, but it cannot always be predicted.

Age and biological response

Bone remodeling is faster in teenagers; in adults, tooth movement can be somewhat slower. However, because adults usually wear their aligners more consistently, the difference in treatment time often evens out. Gum health, bone density and certain medications can also affect the speed of movement. These are assessed at the examination.

Additional procedures

Procedures such as IPR (removing a small amount of enamel between teeth), wearing elastics and replacing attachments are part of treatment, and if they are not done on time, the teeth wait. That is why missing check-up appointments directly lengthens treatment.

What are the typical treatment times by case type?

• Mild crowding (6–9 months): Slight overlapping of the front teeth, minor relapse after braces, gaps of 1–2 mm. Usually 10–20 aligners.
• Moderate crowding and gaps (12–18 months): Noticeable overlapping, multiple gaps, a mild deep bite or open bite, teeth needing slight rotation. Usually 25–45 aligners; a refinement series is common.
• Complex cases (18–24 months or more): Severe crowding, lack of space requiring extractions, significant bite problems, rotation of several teeth, creating space before an implant. 45 aligners or more; one or more refinement series is likely.

For detailed information by type of crowding, gap and bite, see our clear aligners for crowding and clear aligners for gaps pages.

Are clear aligners faster than braces?

Both methods depend on the biological speed of tooth movement; teeth do not move faster with aligners. In mild and moderate cases, clear aligners and braces finish in similar times. Because planning is digital and there are no emergencies (a loose bracket, a poking wire), clear aligners can shorten total treatment time in some cases. In complex cases, braces sometimes deliver results in a shorter time. For a comparison, see our clear aligners vs. braces page. The effect of acceleration devices and methods is scientifically debated; ask your orthodontist for their opinion on this.

Which mistakes make treatment take longer?

• Wearing the aligners less than 20 hours a day
• Changing aligners earlier or later than scheduled
• Not using chewies (silicone rolls that seat the aligner); when the aligner does not fit fully, the tooth does not move
• Not reporting a lost or broken aligner and waiting without one
• Postponing check-up appointments
• Neglecting elastics if they were recommended
• Not getting problems such as gum inflammation and cavities treated

You can find what to do about each of these problems on our clear aligner problems page.

What can you do to finish treatment on time?

1. Take your aligners out only for meals, hot drinks and brushing; keep track of the time from the moment you take them out.
2. Chew on a chewie for a few minutes every time you put in a new aligner.
3. Save your aligner change days as phone reminders.
4. Keep your previous aligner as a backup; if the new one gets lost, wear the previous one and call the clinic.
5. Go to check-ups on time; do not put off problems until the next appointment.
6. Brush after every meal and put your aligners back in right away.

What will you see, and when, during treatment?

In the first 4–8 weeks, the change is usually not noticeable in the mirror; the teeth move in small steps. From month 3 onward, alignment of the front teeth becomes clearer. By month 6, most mild cases reach the finishing stage, and in moderate cases the main correction is visible. The final months are the fine-tuning period: small rotations, settling of the bite and the refinement series. The week-by-week experience is described on our clear aligner wearers page, and the change in the teeth is illustrated with representative drawings on our clear aligners before and after page.

In short, how long clear aligner treatment takes is determined by the complexity of your case and how consistently you wear your aligners. The estimated time is given by your orthodontist after digital planning and may be updated during treatment.