How do Invisalign® aligners work? / What are attachments and buttons?
The aligners you wear with the Invisalign® system are entirely different from traditional braces. And you might wonder, just how do they work?
How can thin plastic tooth aligners straighten a person's teeth?
With removable braces (like Invisalign® but also the systems ClearCorrect® and Simpli 5®), it's the way each aligner fits over your teeth that produces the forces that straighten them.
Each aligner is "ill-fitting" on purpose.
When you first start wearing an Invisalign® aligner, you'll probably notice that it doesn't seem to fit quite right. It may feel snug, or even too tight. It might also be hard to get in and out.
That's because the aligner isn't shaped to fit your teeth. It's shaped to fit the alignment that your teeth need to have at the end of the two weeks when you're finished wearing it.
Each aligner is responsible for just one step of your treatment.
When your Invisalign® aligners are made, each one is fabricated on an individual dental cast.
The alignment of the teeth on that cast represents one individual stage of the series of stages that will, collectively, be used to straighten your teeth.
Each aligner just repositions specific teeth.
Since each aligner has a shape that represents the future alignment of your teeth, not their current one, when it's worn it won't "fit right" in some regions. Encased in these areas are the teeth that the aligner has been designed to reposition.
It may be just a few teeth, or possibly many. It just depends on what tooth movements are called for at this stage in your treatment plan. (That series of tooth movements shown in your treatment animation.) It's common that specific teeth are moved with some initial aligners so to create space into which, later on, other teeth can be moved using following aligners.
It's the "misfitting" aspect of the aligner that causes you teeth to shift.
When an aligner is worn, its "misfitting" region will apply a constant, gentle pressure to the teeth that lie underneath. (The teeth it has been designed to move.) And, gradually, this pressure will guide your teeth into a configuration that perfectly matches the aligner's design. (This stage may involve some discomfort, use this link for details and remedies.)
As evidence of this, you should notice that during the two weeks that you wear an aligner, and especially during the first few days, its fit will gradually become more relaxed. This isn't because the aligner has changed or deformed but because the alignment of your teeth has conformed to its shape.
When you've finished wearing that aligner, you've completed one step of the many that, collectively, will accomplish straightening your teeth.
Each aligner only straightens your teeth just a little bit.
The amount of tooth movement that each individual aligner produces is small. Usually, each one's designed to move its selected group of teeth only about .25 millimeters. That's on the order of about one one-hundredth of an inch.
That may seem small. But after a whole series of aligners has been worn (10, 20, possibly even 30 or more), the total amount of tooth movement that can be accomplished can be quite substantial. Enough so to take a crooked smile and turn it into a perfect one.
What are Invisalign® "attachments"?
Some patient's treatment will require the use of "attachments." These are small tooth-colored dots of dental bonding that are placed at precise locations on specific teeth.
Why are attachments needed?
Some types of tooth changes are difficult to accomplish with removable braces.
It might be that the movement itself is a challenge, such as tooth rotation or extrusion (pulling a tooth up or down into place). Or possibly the tooth has a shape or angulation that makes it difficult for the aligner to direct pressure to it.
In these situations, the dentist will place an attachment. The idea is that this dot of bonding provides an anchor point, one that helps to direct the forces of the aligner more effectively to the tooth.
Your dentist can tell you if your case will require the use of attachments.
Even before it's begun, your dentist will be able to tell you if any portion of your treatment will require the placement of attachments. Your Invisalign® (ClinCheck®) treatment simulation will show where they will need to be placed.
How obvious are Invisalign® attachments?
How much your attachments show will depend on: 1) Where they are placed, and 2) How well the color of the bonding material used matches the color of your teeth.
A worst-case scenario.
The most difficult situation is one where the patient's attachments must be placed on the front side of their front teeth, and their tooth color is not an exact match with any of the shades of dental bonding that the dentist has to offer.
How are Invisalign® attachments placed?
Having attachments placed is simple. It involves the same basic bonding technique that is used with many other dental procedures. And don't worry; no anesthetic (shot) is needed.
Attachments are placed using a template.
Your dentist will receive a clear plastic template from the Invisalign® people. It will look pretty much just like a regular aligner, with the exception that it will have small bulges in it that correspond to specific locations, on specific teeth, where your attachments need to be placed.
Your dentist will clean and prepare the surface of your teeth and then fill the bulges with tooth-colored dental bonding. They'll pick a color that matches your teeth as closely as possible. They may even ask your opinion about that.
The filled template will be seated over your teeth and your dentist will set the bonding using a blue-colored light. Once it's hardened, your dentist will then remove the template. The small dabs of bonding, your new attachments, will remain on your teeth.
Attachments can be a minor nuisance.
Having attachments shouldn't be a big issue. But there are some aspects of having them that can be annoying. For example, when you're not wearing your aligners, you may find that your attachments feel rough to your lips, tongue or cheeks. With time, however, you should get used to them, at least somewhat.
When you eat, you may find that foods get stuck on them. So, be careful if you're eating in public. The fit of your aligner over its attachment can be quite snug. And this can make putting it in and taking them out difficult, or even painful.
How are attachments removed?
Removing attachments is easy. Your dentist will simply use their dental drill and buff the surface of the attachment until it has been completely polished off. This is a painless procedure. No anesthetic is needed.
What should you do if you have an attachment come off?
Every tooth's attachment is placed for a reason. And if you have one come off, you should let your dentist know immediately so they can replace it.
Remember, an attachment provides an anchor point that allows your Invisalign® braces to more effectively control that tooth's movement. If an attachment is lost, your aligner may not be able to accomplish the task that it was intended to provide.
What are Invisalign® "buttons"?
"Buttons" are the term Invisalign® uses for small plastic brackets that serve as anchors points for elastic bands.
As examples, one button may be placed on an upper eyetooth and the other on a lower molar, with an elastic running between them. In other cases, the second anchor point for the elastic is sometimes the Invisalign® aligner itself.
When are buttons and elastic bands needed?
Just as with attachments, buttons and elastics are used to assist the dentist in creating tooth movements that the aligners, on their own, would otherwise have difficulty making.
Your dentist will be able to tell you, before your treatment is begun, if buttons and elastics will be required.
How are buttons placed?
Buttons come pre-made, from Invisalign®. They are bonded onto your teeth using a simple process that requires no anesthetic.
How much do buttons show?
A dentist will typically position a button close to the tooth's gum line (so there's clearance between it and the aligner) Of course, no matter where your buttons are placed, the elastic running to them will be obvious. Choosing clear or ivory colored bands can help them to blend in.
Invisalign® is new and different but it makes use of standard orthodontic techniques.
The fact that Invisalign® (or the similar products ClearCorrect® and Simpli 5®) straightens your teeth via use of removable plastic aligners does make it quite a bit different from having traditional braces. But beyond that, it's business as usual. Removable tooth aligners accomplish their goals using the same basic orthodontic techniques that have always been used.
For more information and example animations, use this link: How standard orthodontic techniques are used with Invisalign®.