• Dr. Tanner

Can Nighttime Aligners Safely Move Teeth?

Updated: Aug 29

Many direct to consumer companies have been promoting nighttime aligners as the newest, most convenient way to move your teeth. These companies make it sound so simple and hassle free – wear your aligners 10 hours a day for about 10 months and presto, your teeth will be straight. Does this sound too good to be true? You bet it is because it runs counter to everything scientifically known about the physiology of tooth movement and long-term stability.


So what are the facts about tooth movement? First and foremost, in order for teeth to move through bone, they need light continuous pressure, which means 20 to 22 hours per day of force. Why is this necessary? When a force is applied to a tooth, the periodontal ligament that surrounds the tooth is compressed on the pressure side and stretched on the tension side. Cells in the bone supporting the root are activated on both sides of the tooth – removing bone on the pressure side and laying down new bone on the tension side. It is important that this physiologic process not be interrupted so that inflammatory response can occur naturally. As a result, light continuous forces allow teeth to move through bone in a healthy and efficient manner.


Now, what is potentially happening with nighttime wear of aligners? When the aligners are placed at night, the teeth feel pressure, initiate the inflammatory process and begin to move as the periodontal ligament is compressed. However, the force load is intermittent (when the aligners are removed during the day) and the teeth immediately begin to drift back to their original position. In addition, the forces of occlusion (inter-arch contacts) during chewing also reposition the newly moved teeth. As a result, this back and forth movement day in and day out causes continuous trauma to the teeth and supporting bone. This is not a healthy environment for the dentition and surrounding structures


So how do these companies get away with claiming that nighttime aligners work? Because they specify that nighttime trays only work with patients who have very minor problems like a small amount of spacing between the teeth or very mild crowding. Even then, the chance of success or long-term stability is greatly diminished with nighttime aligner wear. Here is another thought – most orthodontists have their patients wear their retainers at nighttime to prevent shifting of teeth – they are not designed to move teeth. They’re used to make sure your teeth settle in place permanently.



Wearing an invisible aligner only at nighttime to correct your teeth is like having a broken foot and wearing a cast only when you sleep Dr. Hurst


Candid, one of the direct to consumer clear aligner companies, even wrote an online letter to their potential customers about their concerns with nighttime aligners. Here is an excerpt from that letter by their co-founder, Dr. Hurst:


“There have been no peer-reviewed studies published to date on the efficacy of nighttime aligners. At the end of the day, we need answers to a few basic questions: What exactly is this new “nightly wear technology”? How does this approach to aligner therapy differ from standard clear aligners? And how does this type of treatment impact one’s bio-physiology?

All that aside, I’ll admit it: Nighttime aligners basically sell themselves: “Now clear aligner therapy is more accessible and convenient than ever!” “Your care, on your schedule!” But, as doctors specializing in orthodontics and dentofacial orthopedics we have a clear responsibility to our patients: do no harm. Without more evidence that nighttime aligners are safe and effective, I can’t support nighttime aligner therapy at this point in time.”


I couldn’t agree more wholeheartedly with Dr. Hurst’s assessment of nighttime aligners: their proven lack of efficacy and their potential for harm. Consumers should not fall for marketing hype. Remember the old adage – if it sounds too good to be true, it probably is too good to be true!


If you have questions about the benefits of Invisalign treatment, please call Visage Orthodontics to schedule a visit with Dr. Tanner, your Santa Fe Invisalign specialist. Dr. Tanner will review everything in detail and develop a customized treatment plan to fit your lifestyle and budget.


A confident and beautiful smile is right around the corner!