How does Invisalign work?

Invisalign is a series of clear, removable plastic aligners, each made to your teeth from a 3D scan, that move your teeth a fraction of a millimetre at a time. You wear each set for about 22 hours a day, change to the next set every week or two as prescribed, and over a few months the series adds up to straight teeth. No brackets, no wires, and you take them out to eat and brush.

This page walks through the whole process as it happens at Toothi, from the first scan to the retainers at the end, so you know exactly what you are signing up for before your consultation.

Teeth sit in bone, held by a ligament. Apply light, steady pressure to a tooth and the bone on the pressure side gradually remodels while new bone forms on the other side, so the tooth drifts in the direction of the push. Braces do this with wires; Invisalign does it with plastic.

Each aligner is made with the teeth positioned slightly ahead of where they are now, so putting it on creates pressure where it is needed. The aligner material (Align’s SmartTrack plastic) is engineered to deliver that pressure gently and consistently rather than in one hard shove, which is why it feels like firm pressure for a day or two after each change and then settles. Over the whole series those small moves add up to the result you saw in your simulation.

Two things make the plastic more effective on harder movements. Attachments are small tooth-coloured bumps bonded to certain teeth that give the aligner a handle to grip, so it can rotate a tooth or pull one down into line. IPR (interproximal reduction) is the polishing of a hair’s width of enamel between teeth to create space where the arch is crowded. Not every case needs either; your plan tells you.

Your consultation at Toothi is free and includes a free iTero 3D scan. The scanner takes a few minutes, is far more comfortable than impressions, and produces a precise digital model of your teeth. From that model you see an on-screen simulation of your predicted result the same day. If your case suits Invisalign Go or Go Plus, your dentist then builds your ClinCheck plan: every tooth movement, in sequence, with the predicted number of aligners and the typical duration.

You review the plan before anything is manufactured. The price is fixed by package and confirmed in writing at this point, so there are no surprises later. If the scan shows your case needs full Invisalign or an orthodontist, we tell you at the consultation and refer you on to a colleague we trust.

Your aligners arrive two to three weeks after the plan is approved. At the fitting we place any attachments, carry out any IPR, fit your first set and show you how to seat and remove them. You leave with several sets and a review date.

From then on the routine is simple: wear the aligners for 22 hours a day, take them out only to eat, drink anything other than water, and brush, and move to the next set when your dentist tells you to, usually every week or two. Wear time is the single biggest factor in staying on schedule, which is why we talk so much about the 22-hour rule. Day-to-day practicalities are covered in living with Invisalign.

We see you roughly every eight weeks to check the teeth are tracking with the plan and hand over the next sets. At the end, if any tooth is not quite where it should be, a short extra series of refinement aligners finishes the job; they are included in every Toothi package. Once your dentist is happy, we fit a fixed wire retainer behind the front teeth and make your removable retainers for night-time wear. Teeth that have moved will drift back without retention, so this stage is not optional.

Invisalign Go and Go Plus, the systems used at Toothi, are designed for the front teeth and premolars and treat most adult cases of crowding, gaps, mild to moderate overbite, rotated or tilted teeth and relapse after earlier braces. Cases needing molar movement, major bite correction or jaw surgery are referred on. Compared with fixed braces, aligners are removable, near-invisible and gentler on the mouth; the trade-off is that they only work when they are in. See Invisalign vs braces for a fuller comparison.

Included in every Invisalign package: iTero 3D scan and ClinCheck · all review appointments · refinement aligners if needed · removable and fixed retainers · Airflow hygiene clean · Boutique teeth whitening. There are no add-ons. Full detail on our fees page and in our Invisalign cost guide.