May 2009, Volume 5, Issue 5
Published by AEGIS Communications
Orthodontic Retainers: The New Reality
Originally, the only retainer option offered by Align was based on a stage in ClinCheck®, Align’s proprietary visualization treatment-planning software program that graphically depicts each stage of movement of each aligner in an orthodontic treatment from start to finish. At the end of treatment, if a stage in ClinCheck represented the patient’s finish, all the practitioner had to do was pick up the phone and inform Align that he or she wanted to have a retainer constructed from that stage. Align then used a digital model of that treatment stage to create a retainer using the same (but thicker) material from which Invisalign aligners are constructed.
Many practitioners today, however, are treating patients with Invisalign as an integrated part of their restorative treatment plan, moving teeth into ideal positions before placing veneers, implants, crowns, and bridges. Because these procedures completely change the morphology of the dentition, it is no longer possible to construct an Invisalign retainer from the final ClinCheck model, because it no longer matches the patient’s final dentition.
Align decided it would be clinically responsible to refine its approach and head in a different direction. The goal: To create a retention solution that would provide maximum retention and arch integrity. “Working retention” should be an inherent quality of the product, defined as having the ability to counterattack potential relapse forces. With this goal in mind, the team assigned to the project set out to better understand how retention really works. They needed to understand this before they could design and create a product that met this key need.
The first area of focus was to test and understand the durability of clear retainers. Dentists were polled to identify the most popular clear retainer materials used today, and the top six were selected for in-depth laboratory testing.
Many other leading clear retainer materials demonstrated failures after as little as 2 months of simulated wear, including one that actually cracked during the forming process. Vivera consistently outlasted all of them.
The testing showed that there is not a clear retainer material today that can withstand the daily forces of wear without breakdown, cracking, warping, and tearing, especially during the time patients need it the most—the first 6 months after treatment, when the potential for relapse is the greatest.
Many excellent clinicians experience 50% relapse in their practices. We have always preached to our patients the critical understanding that retention is for life, but are we giving them the tools to be able to follow that philosophy successfully? We have always put the blame on the patient and their diminished cooperation over time. However, these tests were performed by engineers and scientists whose only goal was to provide accurate results. These results challenge what has been considered an established philosophy. We want a patient in lifetime retention, yet we only provide one retainer to clinically meet this goal.
In fact, it now becomes critical for us to know the actual working retention lifecycle of the retainers we use, so we can predict when to replace them to maintain arch integrity.
Although we have found that the material in Vivera retainers lasts longer than the materials in other leading clear plastic retainers, the material in all clear plastic retainers breaks down over time. This is exactly why the Vivera delivery model was created—a series of retainers that are delivered over time to help ensure patients stay in working retention. If your patient is put into full-time wear, each Vivera retainer should be replaced approximately every 3 months. Alternatively, if the patient is placed into nighttime wear only, each Vivera retainer can be expected to provide effective working retention for a much longer time—an average of 9 months. When a patient is asked to reduce wear to 3 nights a week, Vivera retainers may last well over a year.
State-of-the-art robotics, CT scanning, and scientific research to create an advanced polyurethane have all been used to create the Vivera retainer system, which has the ability to self-correct, back to the final retained position, certain types of relapse (up to 0.25 mm) that may occur during the prescription period. Since PVS impressions can now be taken to create the retainers, Vivera is available to any patient in your practice, with the added benefit of having a digital model of your “orthodontic finish” always available. The retainers are made using the same multi-million dollar manufacturing process as the Invisalign aligner system to achieve the same fit and finish and comfort as Invisalign.
These unexpected findings will ultimately have the greatest impact on the dental community in the future. That a piece of plastic undergoes physical and chemical attack on a constant basis, thus limiting its ability over time to maintain arch integrity and fight against relapse forces, makes complete and total sense. For those of us who are constantly dealing with the cost, time, and aggravation of relapse, what a pleasure it will be to be able to provide effective retainers at the appropriate time to maintain effective retention.
This article was written by Dr. Lou Shuman, DMD, CAGS. He recently served as Vice President of Strategic Relations for Align Technology for 6 years and he also was the professional and clinical lead on multiple concept-development projects at Align, including Vivera.
For more information, contact:
Align Technology, Inc.
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