Common Questions
1. Is Zendura a new material?
Zendura material is modern, but not new. The first generation of Zendura was developed out of specific needs of a US major clear aligner treatment company in 1999 by Dr. Ray Stewart and material scientists at Bay Materials, LLC. Zendura was first introduced in 2005 with advanced stress retention property and clarity, and approximately two million aligners have been produced with Zendura by leading aligner orthodontic companies such as ClearCorrect since then.
2. How is Zendura different from other retainer/aligner materials?
Most, if not all, other retainer/aligner materials have been based on polymers that are available "off the shelf" in sheet form. Zendura is robust rigid polyurethane system (see MSDS), which was developed specifically for dental applications, and optimized to have the correct balance of properties including strength, ductility, chemical resistance, clarity, and resistance to stress relaxation.
Polyurethane resins have a number of advantages for manufacturing orthodontic products. The Zendura material is comprised of both polar and non-polar molecules which segregate into micro domains of “hard" and "soft" segments. While in distinct phases, these hard and soft materials are chemically bonded together. By combining hard and soft molecular domains, Zendura achieves both high strength (from the hard regions) and high toughness (from the soft regions). Additionally, the urethane resin is very resistant to staining and accumulation of deposits, allowing it to stay clean and clear longer.
Most of the other commercially available materials, for example PETG, lack at least two of these critical performance properties.
3. Must I use a pressure forming machine to form Zendura?
Although Zendura is suitable for both pressure and vacuum forming machines, a pressure molding machine will achieve a superior definition and fit, and are always suggested.
A pressure forming machine will apply as much as 90psi to form the appliance while a vacuum forming machine can (at most) apply 14.7psi -- a difference of 6 to 1 in applied pressure. Zendura, being a tough material, benefits from the increased force a pressure molding machine generates, and usually has superior definition and fit when formed on a pressure forming machine.
A properly formed Zendura dental appliance will illustrate good definition of gum line and gingival texture. Whether you use a vacuum former or a pressure former, we offer the below picture for you as a reference.
4. Is Zendura a FDA approved material?
Given that Zendura was developed from scratch to be applied in the oral cavity as a medical device, its base components were selected for bio-compatibility. Zendura has been independently tested and passed Systemic Injection, Intracutaneous and Intramuscular Implant biocompatibility tests.
Several devices made from Zendura have been qualified by the FDA. For example, ClearCorrect with 510 (K) and is also CE-marked in EU and TGA approved in Australia.
5. Who are Zendura’s customers?
Since 2010, ClearCorrect has been using Zendura exclusively for its aligner orthodontic system, with a strategic alliance established between ClearCorrect and Bay Materials dedicated to advancing the aligner material technology.
Zendura is supplied to doctors and dental labs seeking the best possible materials in many countries including the US, Canada, Europe, the middle east, China, Australia and more.
6. Why Zendura is packaged in a foil bag?
Zendura is crafted from a polymer that has a natural "thirst" for moisture. If it is allowed to absorb moisture, the water will steam off during thermoforming, and cause blisters and bubbles. We go to great lengths to ensure Zendura is dried and individually packaged in "high barrier" foil bags to provide the best possible final appliance. For this reason, we strongly suggest that Zendura sheet be used quickly after opening the foil bag, preferably within 15-20 minutes. Those who live in a humid environment should take extra care to minimize Zendura exposure to the atmosphere, prior to forming (e.g. Only opening the package immediately before the forming process).
7. Does Zendura contain the BPA molecule?
Zendura is polyurethane based and contains no BPA.
BPA is a base monomer used to make Polycarbonate. BPA monomer is usually only found in trace amounts in products that are fabricated from polycarbonate resins.
8. What types of dental appliance can be fabricated with Zendura?
Given Zendura was developed for the aligner therapy market; it is considered the benchmark for comprehensive orthodontic and minor tooth movement applications. (See fabrication guide.)
In addition, orthodontists and dentists have requested access to Zendura for use in conventional applications such as retainers, temporary bridges, bleaching trays, surgical splints and other applications where structural integrity is particularly important. We have constantly received feedback that the material has been exceptional in such applications.
9. Why do Zendura sheets have a matte finish on one side?
The matte finish of the Zendura sheet is an engineering outcome of a proprietary material processing technology developed by Bay Materials to bring ideal optical transmission when used in patients' oral cavity.
When thermoforming, follow the instructions and place the matte surface up on the frame if using a flip-over type of thermo former or place the matte down if using a vertical type of thermo former, the matte texture will anneal and fuse into a smooth finish on the final appliance, leaving an exceptionally clear, good looking appliance. (See molding & trimming)
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