Align Technology responds to my post about Invisalign Mandibular Advancement
Last week I posted about Invisalign Mandibular Advancement. Invisalign felt that some of my statements were not correct. As a result, I offered them a post to address their concerns.
This has been written by Dr Beena Harkison, she graduated in Dentistry from the University of Witwatersrand. She has a post-graduate qualification in implantology. She joined Align Technology in 2007 and is now Director of Clinical and Professional Education for Europe, Middle East and Africa (EMEA).
I would like to take the opportunity to comment on your recent blog post about one of our recent innovations, Invisalign Treatment with Mandibular Advancement. We realise that you and your readers have some questions regarding the aligner feature which I will address and I’d also like to clear up a few misconceptions that we saw in your blog post.
Introduction to Invisalign Mandibular Advancement:
Invisalign Treatment with Mandibular Advancement is a clear aligner solution for Class II correction in growing teenage patients. It is aimed at patients between 11-16 years old in the growth spurt that present with retrognathic Class II malocclusions in a permanent dentition or in a stable late mixed dentition (stable E’s are necessary during the mandibular advancement [MA] phase), as per the descriptions below:
This new offering combines the benefits of advancing the lower jaw forward while simultaneously aligning the teeth. The Class II correction can be achieved in single or multiple jumps as indicated in the prescription form (or through the ClinCheck plan modifications) by the treating doctor. Doctors can select to either stage the MA with 2mm incremental advancements (every 8 stages/aligners) to the end of the MA phase or may choose a single advancement to the end of MA set-up position. For increased flexibility, doctors can also select their end of MA position as edge-to-edge or the lower arch to be 1 mm or 2mm beyond the edge to edge position.
A screenshot of the prescription form for MA is below:
Additionally, doctors can prescribe additional techniques and mechanics to support a full CII correction in the following scenarios:
- Severe, full cusp Class II malocclusion > 6mm may require Class II elastics.
- Dolicho-facial/vertical growth patients, open mouth breathers may require vertical elastics.
- Grinders may require vertical elastics and extra vigilance on wing engagement.
Invisalign Treatment with MA was clinically evaluated in a multicentre prospective IDE Clinical Study in North America. 10 clinical sites were involved in the study, and 40 patients were analysed. The average patient age was 13.2 (±2.1). 53% of the patients were male, 47% female. The study methodology included before and after records (photos, study models and radiographs), a pre- and post-treatment Quality of Life Survey and cephalometric analysis (completed by a third party; University Faculty). The average number of MA aligners/arch = 36.3 (±17.3) and the average MA phase was 13.4 months (±5 months). Cephalometric analyses were also completed for the 40 patients (outlined in the table below):
The table above demonstrates the dental changes (1stMolar Rt, 1stMolar L and overjet) and skeletal changes (SNB, ANB, Wits Appraisal, Convexity) that were seen, all of the values with p-value < 0.0001. Additionally, IMPA showed limited lower proclination. Thus, demonstrating that Invisalign clear aligners with MA can effectively treat CII malocclusions in growing patients. To date, over 17,000 teenagers have used Invisalign with the mandibular advancement feature. As we continue to add more data to this IDE study (and from the 17,000 treatments in progress), we hope that we will be able to present this to you in a future blog.
For those that are interested in learning more about Invisalign Treatment with Mandibular Advancement, the link below will re-direct you to a webinar hosted by one of the principal investigators of the IDE study, Dr Barry Glaser, accompanied by Dr Milos Lekic.
Emeritus Professor of Orthodontics, University of Manchester, UK.