New 2017 Study shows Invisalign only 50% effective v. Braces

 

New 2017 Study shows Invisalign only 50% effective v. Braces

I have previously reviewed several articles concerning Invisalign and other clear aligner systems used to move teeth and there is a fair amount of debate at the specialty level of Orthodontics as to how much we should be using these aligners and how they are abused in so many inexperienced dental offices.  In fact, previous studies have shown Invisalign to have a dismal 41% mean accuracy of tooth movement with a range from 18% to 47.1% (j.ajodo.2007.05.018;www.ajodo.org) and mean percentage of single tooth movement goal of only 57% (j.ajodo.2013.10.022). 

 

When results from Invisalign were compared to traditional braces using American Board of Orthodontic standards, the Passing rate of cases treated with Invisalign were 27% lower (j.ajodo.2005.06.002).  Even worse, another more complete study (j.ajodo.2004.07.016) actually concluded that there was a “minimal improvement in occlusal score based on Board standards from 47 to 36.4 [0 being ideal] and there was a negative change (2.5x worse AFTER treatment) in posterior occlusion contacts with Invisalign.”  

 

This last investigator summarized Invisalign treatment by stating “According to the OGS [Objective Grading System used for the American Board of Orthodontics], Invisalign did not treat malocclusions as well as braces … Invisalign was especially deficient in its ability to correct large anteroposterior discrepancies [overjet] and occlusal contacts.”

 

Last month (April of 2017), a new article was published in the Journal of the American Association of Orthodontics that confirmed previous findings.

The finding s of the new article from April 2017 (http://dx.doi.org/10.1016/j.ajodo.2016.09.022) , are summarized below.  

Management of overbite with the Invisalign appliance

Roozbeh Khosravi

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“Our results suggested that about 1.5 mm of overbite improvement can be expected when the Invisalign appliance is used in deepbite patients. A previous systematic review on the stability of deepbite correction reported an average of 3 mm overbite correction with fixed appliances [traditional braces].¹³ Our result of a 1.5-mm median correction in open-bite patients is half of the reported average open-bite correction with a nonsurgical fixed appliance approach.²⁵ These comparisons may indicate that aligners can usually improve deepbites and open bites, but they might not accomplish as much correction as fixed appliances.”

Two things to draw from this study:

1. Overbite was corrected on mild cases an average of 1.5mm
2. Overbite corrected by traditional braces for mild cases averages 3mm
3. Traditional braces correct 100% more of the overbite than Invisalign on average.
4. Invisalign is only 50% as effective as traditional braces in correcting overbite.

So relative to braces, Invisalign is half as effective and therefore not clinically sound method to treat when we can treat 100% more with traditional braces.  And this is only one part of a malocclusion a patient may have.

Another area of malocclusion was also evaluated; mild anterior openbites.  This study only looked at patients from three Invisalign offices that had already filtered out the moderate cases for surgery (the author does not state if these discounted cases could have been treated with traditional braces or what those patients did for treatment).

Even with these more moderate to severe cases not included, this study shows that Invisalign cannot intrude or push teeth back into the bone as braces can, in fact all of the bite closure for even these mild cases was through folding the incisors back and down; no mention was made as to the effects on the gingival display (gumminess) and no long-term information was gathered to evaluate for relapse.  This is especially a weak point since these cases (and extrusion of teeth in particular) has been shown in Orthodontic literature to relapse over and over.

In fact when it came to evaluating the post-Invisalign cases, the author simply states the following:

“The second limitation of this study was that almost 50% of screened patients were not included because of the absence of posttreatment cephalometric radiographs. It is unknown whether this might have introduced selection bias to this study.”

 

In other words, if the doctors didn’t take post-Inivisalign records (for instance the results were not good and they didn’t want to have them in the study), they were simply not included in the study.  So we can safely assume this study is full of the best cases only with any failures filtered out of the averages.

 

But even with the results skewed to the most successful treatments, Invisalign is simply not close to the effectiveness of traditional braces.  They are bound by the limitations of a removable tray that has to be loose enough to be removed and over time, fatigues and becomes essentially inert.  Even Invisalign studies show that any tooth moment occurs the first 48 hours of the tray and the next few weeks really show no movement.  This is a clear sign that tray cannot produce the constant forces necessary to make full tooth movmennts.

 

So if the research is so plain and clear, who is pushing Invisalign to the public?

 

The problem now stems from profit-based corporate companies like Align Technologies (Invisalign) and other brands such as Clear Correct and Smile Club advertising directly to the public as if Orthodontics is no different than a trip to the salon and similar to whitening your teeth.

 

Doctors now invested in Invisalign (such as those in this study), also will make statements suggesting relative success in corrections without telling the public that 50% success means 50% failure when compared to braces.  I wouldn't accept a 50% in a grade from any of my four kids and I certainly wouldn't be bragging about a 50% result v. another Orthodontist's cases but that is exactly what Invisalign and Invisalign doctors are saying and many times it's because they know what the public wants and don't want to lose business even though they know there is a better treatment.

 

In fact, Orthodotics is very complex, so much so that it takes two to three years of specialy traingin After dental school to be called a Specialist or Orthodontist.  Companies will lead you to believe a computed scan with a tech can plan and align your teeth equal to traditional braces and this is simply not the case.

Consider sticking a pencil into a soft wax candle jar.  Now imagine simply pushing the pencil over with finger pressure; the pencil will move but will tip.  Now grab the pencil tight and try to move it completely sideways through the wax.  This will illustrate the difference between Invisalign (tipping) and traditional braces (true root movement).  Without the later, there is no way to correct teeth in all three dimensions and any correction from tipping will likely lead to significantly more relapse.

 

                            So are so many doctors now advertising Invisalign?

 

1. It is all General Dentists can do without training for braces.
2. Orthodontists are losing referrals to General Dentists who now believe they can treat their patients and keep everything “in-house” so they are trying to keep their patients.
3. Advertising by a Billion dollar public company is telling patients that clear aligners can give them a smile (though they neglect to talk about function/health) and that braces are essentially “old technology” and not necessary.
4. Align Technologies threatens lawsuits against criticism of their product; they are protecting their profit by any means.  They also pay doctors to use their product by offering free advertising, referring patients directly to doctors that treat more with Invisalign and they donate to all levels of the dental organizations.

 

So why should you care?

 

There is a reason that all dental offices in the state of Texas must be owned by a licensed dentist; only a dentist can be truly held accountable for dental care.  Companies have only one primary objective: profit.  IF they can get profit from a great product then by all means, good for them.  But if they rely on borderline false advertising or advertising by omission to push their product then the patient gets compromised treatment that will lead to relapse, recession or bigger functional problems years later. 

 

Patients should always ask their doctor: Is this the best treatment?  How would braces be different than aligners?  Patients should also avoid any doctor who only offers Invisalign since we know from the literature that Invisalign is only 50% as effective as braces for even minor movements correctible by traditional braces.

 

If a patient accepts to treating to a lesser standard without having to wear braces (and is aware of any risks of functional disturbances in their occlusion afterward), then there is no problem. I personally would never treat and leave a patient in a functional malocclusion out of pure liability because I plan on practicing for many years but if a patient wants this and goes somewhere and they disclose the limitations then at least it is an inform decision. 

 

How do I know my General Dentist treated me to a Functional Bite?

The best way to check your bite after treatment with Invisalign by a general dentist is to have a certified Orthodontist see you after treatment.  Be up front, let them know that you have treated with aligners but that you just want to make sure there are no big issues functionally.  Usually, a good Orthodontist will just keep to the big stuff; he or she is not looking to re-treat patients or openly criticize someone else’s work, but they will now be responsible for identifying any problems and informing you of potential issues.  Keep in mind, aligners are rarely going to provide ideal occlusion simply due to the plastic between the teeth and due to any jaw shift that changes the bite from before the aligners to after (all trays are made from the initial scan and may only be altered once during the entire treatment).  Regardless, large problems that can lead to recession, damage to teeth and damage to joints will have to be disclosed.  From there, you can decide what path to take but at least you will know.

If you have questions or comments concerning this or any orthodontic question, please feel free to make a complimentary new-patient appointment at either my Steiner Ranch location or my North-central Austin location on West 35^th street and MoPac.

 

 

 

Dr. James R. Waters is a 1996 graduate from UTHSC Dental School in San Antonio, 1997 graduate of Advanced Dentistry from the UNMC in Nebraska and the 2001 Valedictorian graduate from the prestigious Saint Louis University Orthodontic Program receiving the J.P. Marshall award for clinical excellence in 2001.  He holds a Bachelor’s Degree in Science, Doctorate in Dental Surgery, a post-doctorate certificate in Advanced Dentistry, post-doctorate Degree in Orthodontics & Dentofacial Orthopedics and a Master of Science Degree in Orthodontics and is a Diplomate of the American Board of Orthodontics.  Dr. Waters and his wife of 21years live in Austin, TX with their 4 children where he has a thriving, multi-faceted Specialist practice with locations in Steiner Ranch and North-Central Austin.  You can learn more about Dr. Waters at BracesAustin.com. 

 

Steiner Ranch Office, Austin, TX

Central Austin office on 35th Street, Austin, TX