The human body can do some pretty amazing things and the action of moving teeth is no exception. Using a combination of biology and chemistry, fixed or removable appliances can shift teeth into a specific position with applied or sustained force.
Of course, the process for fixed ‘bracket-and-wire style’ braces is easier to understand. Archwires are attached to brackets which are then tightened manually by the dentist. Tightening applies pressure to the teeth, which, in turn, causes them to shift in a controlled way. But how does Invisalign move teeth without brackets or wiring?
Essentially, aligner-style appliances like Invisalign work in the same way as fixed braces by gently capturing the forces of tension and compression to manipulate teeth. It’s just carried out differently.
Let me explain…
Exploring the dynamics of tooth movement – Invisalign style!
To better answer the question ” how does Invisalign move teeth?” let’s compare it to a cartoon. Cartoons are essentially a series of animations. Each animation or movement is made up of many individual frames that differ slightly from the previous or subsequent one. When viewed in quick succession, they create a collection of cohesive movements that result in a watchable cartoon. The same can be said for Invisalign aligners
Imagine each aligner as a single frame. When worn over the teeth, each tray has a specific task, in the case of the first aligner, that task is to move the tooth just 0.2mm-0.3mm from position A to position B. After approximately 2-weeks, aligner number one is discarded and the next aligner in the series takes up the mantle, moving the tooth a similar distance from position B to position C. The process is repeated over and over until the teeth have reached their final desired position.
Essentially, if you were to watch the process back on fast forward like a cartoon, you’d see the seamless transition from an uneven to a beautifully straight smile.
Now here’s where it gets interesting…
When an aligner is worn over the teeth, it’s cleverly designed to apply an exacting amount of tension on one side of the tooth and pressure on the other. Doing so triggers the body’s natural responses in the form of bone-building and bone-destroying cells known as osteoclasts and osteoblasts. Osteoclasts break down the tooth-supporting bone to initiate movement, while osteoblasts shore the movement up by rebuilding bone on the other side of the tooth. As you shift from aligner to aligner, teeth will be in a constant state of movement as bone tissue is continually being destroyed and rebuilt.
But there’s more…
When sustained forces are applied, it also triggers a biomechanical response at the periodontal ligament (PDL). The PDL is essentially an elastic fibrous membrane that attaches the tooth root to the alveolar (jaw) bone. When the PDL senses force being applied, it too compresses and stretches to accommodate the tooth’s new position.
Studies show that the remodelling process for the PDL occurs relatively quickly after forced loading by the aligner (typically within the first 24 hours). This is why aligners feel tight when first worn and subsequently feel better as the days go by.
Now we know the science behind how Invisalign moves teeth, we really should talk about what that process actually feels like for the patient. In other words…move teeth
What should patients expect?
Although there appears to be a lot going on under the surface, patients shouldn’t feel much discomfort at all. In fact, Invisalign wearers are encouraged to continue with normal daily activities.
What someone may feel is a dull aching sensation emanating from the teeth, particularly in the early stages of a new aligner. This is a good sign that the aligner is doing its job and movement is taking place.
As the tooth moves further into position inside the confines of the aligner, any discomfort should dissipate within a few days. This is why Invisalign aligners will often feel more comfortable after the first 24-48 hours.
As a top tip, if you’re due to change an aligner, do it just before bed. This way, the majority of the discomfort (if any) will occur during sleep. You can always pre-empt any discomfort by taking a painkiller before going to sleep if you prefer.
Most importantly, just like conventional braces, patients should get used to wearing Invisalign aligners, For the vast majority, orthodontic treatment with clear aligners is a comfortable experience and with millions of worldwide users, they remain a popular solution for those looking to straighten their teeth discretely without the need for visible brackets and wiring.
So there you have it. Hopefully, I’ve given you an answer to the question “How does Invisalign move teeth?” as well as telling you what you can expect during treatment.
If you want to know more about how clear aligners can help, get in touch with your local Invisalign dentist today.