How Do Clear Aligners Work? Step-by-Step

Series of clear aligner trays arranged in treatment order

Clear aligners can seem almost magical — smooth plastic trays that gradually straighten your teeth. In reality, they work on a well-understood orthodontic principle: gentle, controlled force applied over time. Here is how the process works, step by step.

The science in one sentence

Each aligner is shaped slightly differently from your current tooth position, so when you wear it, it applies light pressure that guides specific teeth toward their planned position. Bone remodels around the moving teeth, and the change becomes permanent.

Step 1: Assessment and digital scan

Your dentist examines your teeth and takes a 3D digital scan (or an impression). This becomes the precise map of your starting point.

Step 2: The treatment plan

Using that scan, a full plan is designed showing how each tooth will move, in what order, and how many aligners it will take. You can often preview the expected end result before you begin.

Step 3: Wearing your aligners

You wear each tray about 20 to 22 hours a day, removing it only to eat, drink anything other than water, and brush. After one to two weeks you switch to the next tray in the series.

Step 4: Progressing through the series

Each new aligner picks up where the last left off, moving your teeth a little further. Periodic check-ups let your dentist confirm everything is tracking to plan.

Step 5: Refinement and retainers

At the end, a few refinement trays may fine-tune the result. Then you wear retainers to keep your teeth in their new position — because teeth naturally tend to drift back without them.

Why wear time matters so much

The trays cannot move your teeth while they sit in their case. Consistent wear is the single biggest factor in finishing on time and getting the result you were shown at the start.