Whatever happened to Invisalign Mandibular Advancement?
In January 2019, I wrote a post about the potentially misleading claims on Invisalign Mandibular Advancement’s treatment effects. This was a new appliance that Invisalign claimed “moved the lower jaw forwards and simultaneously aligned the teeth. I was assured that research data was “coming out soon”. So I thought that I would carry out a quick search to see if I could find any more data.
Firstly, I had a look at the Invisalign Mandibular Advancement website.
On the first page they stated;
Invisalign clear aligners with mandibular advancement:
- Straightens the teeth
- Have precision wings that push the lower jaw forwards
- Deliver results you will be smiling about
“With Invisalign clear aligners with mandibular advancement, you can straighten your teeth while the precision wings move the lower jaw forward, replacing bulky appliances.”
I also had a look at the Doctor’s section of the same website. There were some Invisalign articles by KOLs showing case reports. They mentioned “mandibular advancement” several times. Now, to me, “mandibular advancement” means moving or growing the lower jaw forwards. As a result, they are making claims that Invisalign Mandibular Advancement changes the skeletal pattern.
Following my initial post Invisalign responded and informed us that they were running a large cohort study. They reported some of the results in their response blog post. The data they presented showed minimal skeletal growth.
Two years later: iI there anything out there?
I did a quick literature search to find any report or journal article about the extensive study that Invisalign was doing. I found very little.
One report I found was from the AAO meeting in 2019 where Dr Barry Glaser did a presentation. (Dr Glaser is a paid KOL for Invisalign). His presentation can be found here.
I have extracted some data from it.
They looked at 40 patients aged 13.2 years who were treated by 10 different providers. The mean duration of phase 1 treatment was 13 months. I looked at the data for overjet and ANB.
The only other information I found was a Master’s Thesis by Dr Blackham from UBC. In this project, he retrospectively looked at 19 patients treated by Twin Blocks and 13 treated by Invisalign Mandibular Advancement. This is the data that I extracted for overjet.
When I looked at this data. My feeling is that there is nothing much to get excited about. The cases appear to be mild, and the amount of tooth movement and skeletal change is low. In fact, when you look at the Invisalign data, they seemed to take a long time to not get very far? I would be expecting to faster overjet correction with any other functional appliance.
What did I think?
Firstly, I cannot help feeling disappointed that there is no additional information from Invisalign two years after my posts. Indeed, this is even more frustrating that the company and the KOLs are still making their claims with very little evidence. Even from their own study.
When we look at the data from the two sources that I found. It is relatively similar. We can conclude that minor overjets are reduced, and there is some skeletal growth. However, this is what we would typically expect from average growth. Furthermore, the amount of “growth” is no different from other functional appliances. Which is nothing much!
In his presentation, Dr Glaser stated that “the correction with Invisalign Mandibular Advancement was similar to other forms of Class II correction”. If we consider that other forms of Class II correction do not change the position of the mandible. Then we cannot call the new Invisalign appliance a “mandibular advancement” appliance.
I will conclude with the same statement that I made in my blog two years ago.
“No, we do not believe your claims”.
This time I will also add
“Invisalign KOLs why are you making these claims”?
Perhaps one of the usual suspects could answer?
Emeritus Professor of Orthodontics, University of Manchester, UK.