“Remember that all is opinion.” – Marcus Aurelius
The topic of orthodontic treatment using clear aligners has long been subject to heated debate. It remains so to this day. (Warning: this will be a long post!)
On the one hand, a number of clinicians regularly claim achieving what they describe as “excellent” results using such appliances, claiming a reduction in chair side time and even overall treatment time, while many others do not really subscribe to the idea that they are an effective nor efficient method of treatment. Unfortunately, the research surrounding the efficacy and efficiency of clear aligner treatment is still very much lacking to date. A search for the term “clear aligner” on PubMed merely brings up a couple of pages of various case reports, editorials, and only a handful of trials that cannot be considered by any means as comprehensive nor conclusive. As such, the debate rages on and probably will continue for a long time, and at the moment, only clinical experience can be sought upon in an attempt to reach a meaningful conclusion, however prone to personal bias that may prove to be.
Before continuing further, I have a personal disclosure to make: I, for one, find myself to be slightly biased on this matter. Personal experience tends to make me biased towards the overall efficacy, efficiency and control that pre-adjusted fixed appliances provide, in stark contrast to my experience and results using clear aligners. This preference is a result of my own personal experience with this kind of appliance over the course of the past 10 years as much as it is due to my review of surrounding literature and observation of many treated cases outside my practice, as well as discussions with an increasing number of colleagues whom – after some experience with such appliances – have come to share my opinion regarding their efficacy. Several of these colleagues have even – unceremoniously- stopped offering clear aligner treatment altogether in their practices, the reasons for which we’ll come to later in this post.
First, let’s begin by reviewing the current “evidence”. Many of the already published research surrounding clear aligners are either partially or wholly supported by the clear aligner manufacturing companies themselves, with one or more authors usually disclosing invested interest in the researched appliance’s manufacturing company. This fact alone should raise a red flag immediately in any kind of published research. No matter how “air tight” the statistics and methodology are projected to be in such studies, some degree of bias is bound to be involved somewhere, sometime within the process of the research. This bias is often extremely hard to notice from reading the research paper alone, and may be part of the actual treatment being delivered during the research – unknowingly even to the researchers themselves. This study, published in The Angle Orthodontist, for example, and is partially funded by a reputable Clear Aligner manufacturing company, set out ” to compare the time efficiency of aligner therapy (ALT) and conventional edgewise braces (CEB) based on large samples of patients treated by the same highly experienced orthodontist, with the same treatment goals for both groups of patients.” The study had two parts, a retrospective part where 150 treated patients were matched and evaluated based on mandibular crowding and number of rotated teeth to a sample of 150 aligner-treated patients, while the prospective study aimed at timing the various appointments of both treatments with a stopwatch, in an effort to compare clinical chair side times. I will not go into the details regarding the statistical methods used, however, the study concluded that Chair-side time was about 50% less for the aligner treatment group, which is understandable considering the adjustment needs for fixed appliances even in shorter visits. However, another conclusion was that their examined “aligner” treatment duration was 67% shorter than CEB treatment, and the reasoning behind this is that aligner treatment does not require a finishing or detailing phase, while pre-adjusted appliance treatments do! The problem for me with this statement is that it defies almost all my actual clinical experience with clear aligner treatments; I have yet to see an aligner-treated patient finish faster than a fixed appliance-treated patient, even for comparable “simple” types of cases. My own, and many colleagues’ personal experiences show that the vast majority of aligner treated patients actually end up either quitting treatment due to inability of the appliance to “fine-tune” and properly finish the last vital details of the occlusion, or end up with a short phase of fixed ceramic fixed appliance to finalize the little details that seemingly no amount of “micro adjustment” and “fine-tuning” of clear aligners are able – as yet – to efficiently provide. Therefore I personally find this conclusion at odds with the clinical experiences of many, including myself. I also find it slightly at odds with the findings of this clinical trial which examined orthodontic tooth movement with clear aligners and found that uncontrolled tipping and loss of anchorage complicate the progression of programmed aligners, and that tooth movement seems to be slower and less efficient during the second week of the aligner set wear, although they concluded this was probably not due to material fatigue, but to the effects of uncontrolled tooth tipping that seems to occur with this kind of treatment. (Again, one of the authors in the second paper also had invested interest by being on the aligner manufacturing company’s board). The experience of the treating orthodontist with the technology surely plays a big role here, however the ultimate deciding factor seems to be the compliance of the patient, as the authors of the first study clearly state themselves towards the end of their article: Patient compliance is absolutely imperative in order for ALT patients to be treated effectively and efficiently. The aligners are removable; whether or not they are worn depends on the responsibility of the patient. With braces, the orthodontist has greater control over the movement and therefore is more effective at treating the malocclusion and predicting the outcome. The efficiency and effectiveness of using ALT in practice is determined by how well patients comply with treatment.
My main clinical issues with clear aligner treatment can be stated clearly as follows:
- Despite of what we would like to believe, a lot of control is actually taken out of the hands of the treating orthodontist. Throughout treatment, you are under the mercy of several “external” factors most of which would never come into play otherwise; the accuracy and consistency of the aligner company’s actual manufacturing process, the technician responsible for handling your computerised treatment setup, the delivery courier that handles your impressions and aligner sets back and fourth. But probably the most important of all, your patient to whom you have almost entirely deferred the success of treatment – much more so than with fixed appliances, and who will ultimately hold YOU, their orthodontist, responsible for any failure or lack of properly-finished results. Personally, I would gladly take responsibility for any treatment failure with a fixed appliance treatment, rather than – grudgingly – be held responsible for failure due to lack of patient compliance or inefficiency inherent to the treating appliance itself! … Patients don’t know what they want until they don’t get it!
- The delay in treatment due to problems with ill-fitting aligner sets, or misplaced/lost sets which require new impressions or scans. Each delay can add up to 2-3 weeks, especially in the Middle East, where I live and practice.
- The initial phase of aligner treatment usually starts off well with noticeable tooth movements and derotations over the first few months. In the latter parts of the treatment and towards the “finishing” phase, the inefficiency of the appliance starts to become quite evident to both patient and doctor, with even minor movements becoming slower and more difficult to achieve.
- If I was a patient seeking aligner treatment for aesthetic reasons and paying such huge sums of money for it, I would expect nothing less than perfection!.. Round-tripping and having to wear a fixed brace at the end to “finish” properly is not really something on my agenda, even If I consent to it at the onset. (Hope is more powerful than fear! I would always have hope I wouldn’t have to have the brace… until I actually find out I really have to!)
- The apparent “ease” of the treatment to the orthodontist is quite deceiving. Younger, newly-graduated orthodontists and many GPs usually fall for this “trap” and start accumulating a large number of incomplete or poorly-finished cases that end-up switching treating doctors to have their issues corrected. (Unfortunately, I see such cases come to my practice on almost a weekly basis!)
All of the above, of course, is not research nor scientific evidence. It is merely a distillation of personal clinical issues I have with this kind of treatment. Some might agree, many more might disagree, and the debate is welcome. However, I do feel they are important issues that need to be considered as they can have a detrimental impact on the overall quality of experience that the patient has in your practice.
As a final note, I wish to point out the conclusion of the first study which was stated as follows: “ Whether the greater time efficiency of ALT offsets the greater material costs and doctor time required depends on the experience of the orthodontist and the number of ALT case starts.” My hope is that fellow orthodontists don’t take this to mean: Hey, Let’s Just increase the number of aligner treatment case starts!
What I hope is that we first look at the published “evidence” more objectively and also use our clinical common sense, in order not compromise effective and efficient treatment results where we know that a more conventional approach can produce a better, faster and often less costly treatment for our patients. Aligner therapy is a perfectly good “idea” that has yet to find its true potential, in my opinion, and I’m always open to changing my mind in the future depending on new evidence or practical improvements in the material, application and technique. Until then, Marcus Aurelius’ above quote stands: “Remember that all is opinion.”
6 thoughts on “Thoughts on Orthodontic Treatment with Clear Aligners”
Another AAO publication to add to the argument:
How well does Invisalign work? A prospective clinical study evaluating the efficacy of tooth movement with Invisalign
Neal D. Kravitz
Results: The mean accuracy of tooth movement with Invisalign was 41%.
Would you buy a phone or a car that is 41% accurate?!
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Indeed!… there’s a lot to think about here. Thanks for your comment Yaz.
I think Aligners work really well when there is a combination of low expectation from both doctor and patient and patient has deep pockets.
Probably the best way to describe it, yes!.. but does this affect one’s own high standards of care?.. I believe it does, especially if the doctor does not offer to the patient an alternative to this requested treatment modality. I have yet to encounter a patient who initially came with the desire to use clear aligners, and did not change their mind after I explained the compromises that may be needed or faced during aligner treatment. Thanks for your comment.
Hello, kindly let me know whenever posts are added to this forum, thankyou
Dear Dr Heeru.. Thank you for your interest in my blog. You can sign up to receive all posts by adding your email through the Follow section at the bottom of this page. Regards