Aligner attachments: the little bumps on your teeth

Attachments are small tooth-coloured bumps bonded to the front of some teeth during aligner treatment. They give the smooth plastic something to grip, so a tray can push a tooth in a direction it otherwise could not.

Align Technology, which calls its version SmartForce attachments, describes them as "tiny, almost invisible bumps placed on your teeth during Invisalign treatment" that "work like handles, giving your clear aligners something to gently push on".

Why a tray needs a handle

A clear aligner is a smooth shell. Pressed onto a smooth tooth, it is good at tipping teeth and poor at rotating them, pulling them down or moving them bodily — there is nothing for the plastic to hold.

An attachment changes that geometry. Each one is shaped for the movement it serves: Align says each attachment "is designed with a specific shape to deliver force in a particular direction". The tray is manufactured with a matching dimple, so the plastic engages the bump rather than sliding over it.

Not every case needs them. Align's own material says an orthodontist "will recommend SmartForce attachments if one or more teeth need more significant movement", and that "not everyone who uses Invisalign clear aligners will need SmartForce attachments."

How they go on

The process is a bonding appointment, and Align puts it at "around 30 minutes" for its own system.

1. The clinician reviews the digital treatment plan and notes where attachments are to sit.
2. The teeth are cleaned and dried so the bonding material will stick.
3. A template tray, filled at the marked points with composite resin, is seated over the teeth.
4. The resin is hardened with a curing light.
5. The template is removed, leaving the attachments on the teeth.

Align's description of removal at the end of treatment is that the orthodontist takes the attachments off in a non-invasive procedure. Any polishing afterwards is part of the same appointment.

Read the list again and notice what it requires: someone physically present, with a curing light, twice. That is the part no courier can deliver.

Attachments, buttons and elastics are not the same thing

Three things get called "the bits on my teeth" and they do different jobs. Attachments are bonded composite shapes that the tray itself engages. Buttons are small fixtures — metal or tooth-coloured — that something else hooks onto, usually an elastic band. Elastics run between points on the upper and lower teeth to move one jaw's teeth relative to the other's.

Knowing which you have been fitted with is worth a question at the appointment, because the daily instructions differ. An attachment needs nothing from you but cleaning. An elastic is a thing you are responsible for changing and wearing, and a plan that depends on elastics depends on you in a way a tray alone does not.

It is also the difference between a case a smooth tray could handle on its own and a case that needs more than plastic. If a plan involves buttons and elastics, that is a signal about the complexity of the work, and a fair prompt to ask what the alternatives are.

What they mean if you were considering a mail-order course

A case that needs attachments needs two chair appointments at minimum, one to place them and one to take them off. Mail-order sellers do not provide those.

This is not a reason to dismiss at-home aligners; it is a reason to know which kind of case you have before you buy one. That, again, comes back to an examination. The FDA's consumer advice is to "make sure you receive an evaluation by a dentist or orthodontist, preferably in-person to determine whether clear aligners are appropriate for you", and whether your case can be done without attachments is part of what such an evaluation establishes.

Why the tray is manufactured around them

An attachment is only useful because the tray is made to match it. The dimple in the plastic is designed at the same time as the bump on the tooth, which is why the two have to be placed exactly where the plan says. A millimetre out and the tray either will not seat or will not engage.

This is also why a lost tray is more of a problem in an attachment case than in a smooth one. The next tray in the sequence is shaped for teeth that have already moved; skipping ahead can mean a shell that will not seat over the attachments at all. Align's advice to parents — keep the previous set as a backup and contact the orthodontist promptly — exists for that reason.

It has one more consequence worth knowing at the quoting stage. Because the attachments and the trays are designed together, a change of provider partway through a course usually means starting the planning again from new records. That is a real cost, and a fair thing to ask about before you commit to anyone.

Living with them

Three honest points, from Align's own description of its product rather than from anyone's experience.

Visibility. Align says the material is tooth-coloured "to be as discrete as possible", and adds that "some attachments may be more visible than others, depending on their location." A bump on a front tooth is easier to notice than one on a premolar, and both are more noticeable with the tray out than with it in.

Comfort. Align says patients "may experience some mild discomfort after initially getting your SmartForce attachments", that it "should not last long" and "can be expected to be mild", and refers to over-the-counter pain relief. What to take, and whether to take anything, is a question for the clinician treating you — this site gives no drug advice of any kind.

Cleaning. Attachments give plaque somewhere to sit, and a tray held against them keeps it there. Cleaning around them is ordinary brushing done attentively, and the tray needs its own routine — see how to clean aligners without wrecking them.

Staining. Composite picks up colour over time, which is one reason clinicians ask patients not to drink anything but water with trays in. A stained attachment is a cosmetic issue during treatment and disappears when the attachment does.

What nobody can tell you from here

How many attachments your case needs, where they go, or whether the case needs them at all. Those come out of a treatment plan built from records of your mouth, and the plan is the thing you are really buying.

If you are still at the stage of comparing prices, every published figure and what it includes is on what clear aligners cost, read at source.