What Are Clear Aligners? A Simple Guide to How They Work

Clear aligners are thin, transparent, removable trays that straighten your teeth step by step, without metal brackets or wires. Each set is custom-made from a 3D scan of your teeth, and you switch to a new set every 10 days to 2 weeks. Treatment takes around 6–10 months on average, depending on your case.

If you've never looked into teeth straightening before, this guide covers what aligners are, how they work, who they suit, and what treatment is really like day to day.

What are clear aligners, exactly?

Clear aligners are a series of custom plastic trays, each shaped slightly differently from the one before. Worn in sequence, they apply gentle, controlled pressure that moves your teeth a little at a time towards a planned final position.

Because they're removable, you take them out to eat, drink anything other than water, and brush. That's what makes them different from fixed braces — and also why wearing them consistently matters so much.

At BASMA, every treatment is planned by a BASMA orthodontist, starts with an in-clinic 3D scan, and is supported by remote check-ins through the BASMA app.

Clear aligners: the key facts

Question	Answer
What are they made of?	Thin, clear medical-grade plastic, custom-made for your teeth
Can people see them?	They're hard to notice in everyday conversation
How long do you wear them each day?	20–22 hours
How often do you change trays?	Every 10 days to 2 weeks, as your plan sets out
How long does treatment take?	Around 6–10 months on average*
What can they treat?	Mild to complex alignment issues, confirmed by your BASMA assessment
Who oversees treatment?	BASMA doctors, with app check-ins and clinic visits when needed

*Treatment length depends on your case and on how consistently you wear your aligners.

How do clear aligners work?

Clear aligners work by applying light, steady pressure to specific teeth. Your bone gradually remodels around each tooth as it moves, so small, planned steps add up to a straighter smile over several months.

Each tray is designed in advance from your digital treatment plan. When one tray has done its job, you move on to the next.

What does treatment with BASMA look like, step by step?

Your treatment starts in a clinic, not in a box. Here's how the journey usually works:

Consultation and dental checkup. You visit a BASMA partner clinic, where a dentist checks your teeth and gums are healthy enough to start.
3D scan and dental photos. A quick digital scan creates an accurate model of your teeth and bite — no messy moulds.
3D smile preview. You see a digital preview of how your teeth are planned to move, before you commit to anything.
Your orthodontist-led treatment plan. A BASMA doctor designs your plan and decides which movements your teeth need.
Custom aligners. Your aligners are made specifically for your teeth and your plan.
Changing trays. You switch to a new set every 10 days to 2 weeks, as your plan sets out.
App check-ins and clinic visits. You share progress through the BASMA app, and visit the clinic when your treatment clinically needs it.
Retainers. Once your teeth are in place, retainers help keep them there.

The BASMA care team is on hand throughout if you have questions between check-ins.

What else might be part of your aligner treatment?

Some treatment plans include small extras that help aligners move teeth more precisely. If your plan needs any of them, BASMA will highlight this in your treatment plan.

What are aligner attachments?

Attachments are small, tooth-coloured bumps bonded to some teeth. They give the aligner something to grip, which helps with movements like rotating or lifting a tooth. They're removed painlessly at the end of treatment.

What is IPR?

Interproximal reduction (IPR) means gently polishing a fraction of a millimetre of enamel between certain teeth to create space. It's sometimes used to relieve crowding without removing teeth.

Refinements are extra aligners made towards the end of treatment if some teeth need a little more fine-tuning. Research suggests many tooth movements aren't fully achieved with the first set of trays alone, so refinements are a normal part of aligner treatment, not a sign that something has gone wrong [2].

Who are clear aligners for?

Clear aligners can suit adults and teens with mild to complex alignment issues, as long as they can wear them consistently. Your BASMA assessment will confirm whether they're right for you.

Clear aligners are often a good fit if you:

Want a discreet option that fits around work and social life
Had braces before and your teeth have shifted back
Have crowding, gaps or bite issues
Can commit to wearing aligners 20–22 hours a day
Are a teen who's ready to manage aligners with a parent's support

Clear aligners may not be the right choice if you:

Have certain severe bite or jaw problems that need braces or surgery
Have untreated gum disease or tooth decay (these need treating first)
Know you're unlikely to wear removable trays most of the day

What problems can clear aligners fix?

Clear aligners can treat many common alignment issues. How well they work for you depends on the cause and severity of your case.

Crowded teeth

Crowding happens when there isn't enough room, so teeth overlap or twist. Aligners can often create space and straighten teeth, sometimes with the help of IPR.

Gaps between teeth

Spaces between teeth are one of the more straightforward issues for aligners to close.

Overbite

An overbite is when your upper front teeth overlap your lower ones too much. Many overbites can be improved with aligners, sometimes with small elastics.

Underbite

An underbite is when your lower teeth sit in front of your upper teeth. Aligners may help when the cause is the teeth themselves; underbites caused by jaw position may need other treatment.

Crossbite

A crossbite is when some upper teeth sit inside the lower teeth when you bite. Aligners can correct some crossbites, depending on whether teeth or jaw width are the cause.

Open bite

An open bite is when your front teeth don't meet when you bite down. Some open bites can be treated with aligners after the BASMA orthodontic assessment.

How long does clear aligner treatment take?

Clear aligner treatment takes around 6–10 months on average. Simpler cases can finish sooner, while more complex cases may take longer.

Your timeline depends on:

How complex your case is
How consistently you wear your aligners
Whether you need refinements towards the end
What your treatment goals are

Do clear aligners hurt?

Clear aligners can feel tight or cause mild pressure for the first day or two of each new tray. This is normal and usually settles within a few days.

Research suggests patients with clear aligners tend to report less pain than those with braces in the first few days of treatment, though the difference fades after that [3]. If discomfort is severe or doesn't settle, contact the BASMA care team.

Are there any side effects?

Most side effects are mild and temporary. You might notice:

A slight lisp for the first few days while your tongue gets used to the trays
Tenderness when you switch to a new set
Dry mouth or extra saliva at first
Staining of the trays if you drink coffee, tea or coloured drinks with them in. We only recommend drinking cool water when wearing your aligners.

What's daily life like with clear aligners?

Most people settle into a routine within the first week or two. A typical day involves:

Wearing your aligners 20–22 hours a day
Taking them out to eat and drink anything other than water
Brushing your teeth before putting them back in
Cleaning your aligners daily with lukewarm water (hot water can warp them)
Keeping your BASMA carry case with you so trays don't get lost or damaged
Uploading progress photos through the BASMA app at the end of each step, and following the instructions you receive

Why do you need retainers after aligners?

Retainers keep your teeth in their new position once treatment ends. Without them, teeth naturally tend to drift back towards where they started — this is called relapse.

A Cochrane review notes that almost everyone who has orthodontic treatment needs some form of retention to prevent relapse [6]. Read more about retainers and how to wear and care for them for longterm retention.

What might your aligner journey feel like?

Imagine you've wanted to fix a small gap and some crowding for years but never wanted metal braces. You book a consultation, get your 3D scan, and see your smile preview the same week. A few days into your first tray, the pressure has faded and you've stopped noticing them at meetings. After your first few steps, you can already see your teeth shifting.

Key takeaways

Clear aligners are removable, custom-made trays that straighten teeth gradually.
They can treat mild to complex cases, and your BASMA assessment confirms what's possible for you.
Treatment takes around 6–10 months on average, with tray changes every 10 days to 2 weeks.
Wearing them 20–22 hours a day is the biggest factor in staying on track.
Retainers are needed afterwards to keep your results.

Frequently asked questions

Are clear aligners safe?

Clear aligners are considered safe when they're prescribed and monitored by qualified dental professionals. That's why BASMA treatment always starts with an in-clinic checkup and is planned by a BASMA orthodontist.

Can you see clear aligners when you wear them?

Clear aligners are hard to notice in everyday conversation. If your plan includes attachments, these are tooth-coloured, so they blend in too.

Can you drink with aligners in?

You can drink plain water with your aligners in. For anything else — especially hot or sugary drinks — take them out, then rinse or brush before putting them back.

Will clear aligners affect my speech?

Some people notice a slight lisp for the first few days. It usually fades quickly as your tongue gets used to the trays.

Can I get aligners if I've had braces before?

Yes, many people choose aligners after their teeth have shifted following earlier braces. BASMA will assess whether aligners can treat your case.

What happens if I lose an aligner?

Contact the BASMA care team. Depending on your stage, they may ask you to wear your previous or next tray while a replacement is arranged.

Ready to find out if clear aligners are right for you?

The easiest first step is a consultation at a BASMA partner clinic. After your checkup and 3D scan, you'll see your 3D smile preview and get an honest answer on what's possible for your teeth — with no obligation to start.

Book your consultation

Sources

Ke Y, Zhu Y, Zhu M. A comparison of treatment effectiveness between clear aligner and fixed appliance therapies. BMC Oral Health. 2019;19:24.
Effectiveness of clear aligner therapy for orthodontic treatment: a systematic review. Orthodontics & Craniofacial Research. 2020;23(2):133–142.
Cardoso PC, et al. Pain level between clear aligners and fixed appliances: a systematic review. Progress in Orthodontics. 2020;21:3.
Timm LH, et al. Effect of electronic reminders on patients' compliance during clear aligner treatment. Scientific Reports. 2022;12.
Factors influencing patient compliance during clear aligner therapy: a retrospective cohort study. Journal of Clinical Medicine. 2021;10(14):3103.
Cochrane Oral Health Group. Retention procedures for stabilising tooth position after treatment with orthodontic braces. Cochrane Database of Systematic Reviews. 2023.