Day & Nighttime Aligners: What Are The Differences?

By Dr. Robert Gire
Southern California

Dr. Robert Gire maintains three private offices in Southern California, Gire Orthodontics of La Habra, Chino Hills, and Ladera Orthodontics in Ladera Ranch. He’s an associate professor at the University of Southern California, Herman Ostrow School of Dentistry in the pre-clinical orthodontic department. He’s a board-certified diplomate of the American Board of Orthodontics (ABO).


Recently, I have been approached by patients asking about the difference in daytime versus nighttime aligners and if I had a professional opinion about them. Because nighttime aligners are relatively new and widespread information has been limited, I thought it would be a good topic for an educational post.

Traditional clear aligners have been around for almost 20 years and there have been millions of patients treated and there’s a plethora of clinical data to support the treatment. Just recently there’s been some discussion regarding the use of exclusively “nighttime” only aligners and due to the recent nature, there is very little clinical data or patient testimonials to review.

For background, traditional aligners are to be worn approximately 22 hours a day. They are made of a nearly clear plastic and are worn in the mouth like a tray. They should only be removed to eat, drink, or brush one’s teeth. Nighttime aligners are to be worn 8-11 hours per day, depending upon the manufacturer, in the evening and sleeping hours.

Be Wary Of Moving Teeth And Jaws Without A Doctor’s Oversight

As an orthodontist with many years dedicated to the craft of carefully moving teeth and supporting structures, I have always cautioned my patients about do-it-yourself aligner products without regular visits to a trusted and trained orthodontist. Orthodontists can ensure aligners are the right treatment method, based on the particular issues a patient needs to address. They closely monitor the patient’s progress and troubleshoot as needed along the way, or even change the treatment method as needed. There are several aligner systems that require an orthodontist’s supervision with visits every couple of months, including Spark, with which I have seen great results for my patients at Gire Orthodontics and Ladera Orthodontics. Other mail-order products do not involve a doctor to monitor the movement of teeth, their roots, and of course the supporting structures attached to them. Some offer a request to do a remote or televisit, if there is an absolute need. Would you set your own broken leg or arm bone if you fell or would you see a trained medical specialist?

Who Manufactures Nighttime Aligners And How Many Hours Do You Wear Them?

There are currently several nighttime products on the market manufactured by various companies that cut out the role of a trained in-person specialist, the orthodontist. It should be noted that these are slightly different from each other and claim different treatment times. All are to be worn 8-11 hours a day. One company utilizes the same nighttime aligner material as its full-time, regular product. So, by wearing the aligners half the time, the treatment time is about twice as long. Instead of wearing each aligner set for one week, each set must be worn for two weeks. Another nighttime aligner brand claims its product is made with a harder material and requires the patient to use a vibrating device that provides micro-pulses for 10 minutes a day. The company claims it can move teeth quicker (4-6 months) than competing products. Another product appears to be similar to its daytime aligner and states average treatment time is 8-12 months, based on the patient wearing it eight hours a day. I do not advocate for products where a doctor’s expertise and follow-through are absent from the treatment process. So, if these interest you, I would strongly encourage you to do your research and make an informed decision based on clinical studies and outcomes data.

Keeping Teeth In Aligners During Treatment

Since Invisalign developed the first clear aligner, all orthodontists have followed their treatment plan guidance and required our patients to wear their aligners 22 or more hours a day. And there’s good reason for it. When a patient removes his or her aligner for more than just a quick bite or brush, the teeth start to shift back to their original positions. The longer an aligner is out, the more the teeth shift. Not only does this lengthen the treatment duration, but it also puts additional strain on teeth as they continually shift in and out of their intended positions. This can cause additional discomfort and, because the aligners are only worn at night, could cause some restless or sleepless nights. One last precaution: there is a small risk with any orthodontic procedure of damaging tooth roots, and with the added strain of excessive movement and the shifting back and forth may cause some concern about root damage. This is something orthodontists will want to study in terms of reviewing long-term data which is not yet available.

The objective of clear aligners is to address simple to moderate cases of undesirable spacing, crowding, or malaligned bites. These are intended for patients who want a discreet treatment journey in a fairly short timeframe and they want it done safely and effectively. Today’s aligners are nearly invisible, especially Spark, with the clearest material on the market. Due to the clarity of the material, there shouldn’t be an issue with wearing them during the day.

For years, dentists and orthodontists have been advising their patients to keep aligners in place for as much of the day and night as possible. It’s not to accelerate treatment. It’s to honor the biology and to support a safe and healthy adjustment process.

Before Making A Choice In Orthodontic Treatment, Do Your Homework

I encourage each patient to do his or her own research and speak to an orthodontist about the right treatment method based on an evaluation of the patient’s particular case and needs.

*The opinions expressed in this article are those of Dr. Robert Gire. Ormco is a medical device manufacturer and does not dispense medical advice. Clinicians should use their own professional judgment in treating their patients.