Invisalign attachments are small, tooth-coloured bumps of composite bonded to certain teeth for the length of your treatment. They give the aligner something to push against, so it can rotate, tip or lift a tooth that a smooth plastic tray on its own could not move. Almost every adult Invisalign case needs some, they are planned before you start, and they are polished off at the end.

They are also the thing patients ask about most once treatment begins, because nobody warns them: the aligner is nearly invisible, but the attachments are the part other people might notice up close. Here is what they are, what they feel like, and what to do about the practical things — stains, snapped-off attachments and all.

An aligner moves teeth by being made slightly ahead of where the teeth are now; the plastic flexes back towards its intended shape and pushes the teeth with it. On a flat, smooth tooth that push can only do so much. Rotating a rounded tooth like a canine, pulling a short tooth down into line, or tipping a root rather than just a crown all need a handle for the aligner to grip. The attachment is that handle.

Each attachment is a specific shape — rectangular, bevelled, sometimes wedge-like — chosen by the software and checked by your dentist for the movement that tooth needs. Teeth that only need a small, simple movement often need none; teeth doing the heavy lifting may need one. That is why two people on the same package can have very different numbers of them.

Honestly: up close, yes, a little. They are matched to your tooth colour and are a few millimetres across, so from normal conversational distance most people never notice them, and with the aligner in they are covered and look like part of the tooth. In a photograph with flash, or if you point them out, they are visible. Attachments on the back teeth are effectively invisible; the ones on upper front teeth are the ones you will be aware of.

Two things help. First, the attachments are tooth-coloured, so they blend better the closer the shade match — which is one reason your included Boutique whitening is done once treatment is complete and the attachments are off, so the final shade is even. Second, they come off at the end, so whatever you notice for a few months is temporary.

• ✓  The first few days. With the aligner out, the attachments feel rough to your lips and tongue and you will run your tongue over them constantly. It settles within a week. A little orthodontic wax helps if one is rubbing.
• ✓  Seating the aligner. Attachments make the aligner grip harder, so it needs pushing fully on and can be stubborn to remove at first. Bite on your Invisalign chewies for a few minutes after inserting each new set to seat it over the attachments properly; a poorly seated aligner is the most common reason a tooth falls behind the plan.
• ✓  Eating. Aligners come out to eat, so the attachments do take the brunt. They are tough, but biting into something hard directly on a front tooth with an attachment can knock it off.
• ✓  Staining. Composite picks up stain more readily than enamel. Coffee, tea, red wine, curry and smoking will yellow attachments over months. Rinsing after eating and brushing before the aligners go back in keeps them clear; stains on an attachment polish off at the end regardless.
• ✓  Cleaning. Brush around and over each attachment; plaque collects at the edges. Your included Airflow hygiene clean deals with anything you miss.

Attachments do occasionally come off, usually on food. Keep wearing your aligners as normal — the plan still works on every other tooth — and message us. We will tell you whether it needs replacing before your next review or can wait until you are in. If a tooth has an attachment doing an important job and it stays off for weeks, that tooth can fall behind, which is the main thing we want to avoid. Replacing one is a short appointment and there is no charge for it; attachments, refinements and reviews are all part of your package price.

At your final visit each attachment is carefully removed with a fine polishing bur and the enamel surface is polished smooth. It takes a few minutes per tooth and does not hurt; you may notice a faint vibration. There is no drilling into the tooth and, done properly, no lasting mark — the bond is to the surface of the enamel, not into it. Your teeth will feel oddly smooth for a day or two. Then it is scans for your retainers, your fixed wire goes on, and the whitening you have been waiting for.

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