Invisalign® disadvantages and problem issues.

- Situations and case conditions where using a removable aligner system may not work well.

Removable braces systems (like Invisalign®, ClearCorrect®, eCligner®, ClearPath®, and Simpli 5®) don't always make the best choice for straightening teeth.

As we outline on this page, this technique has some limitations and disadvantages (both actual and potential) that may make it difficult, or even impossible, for your dentist to produce an ideal, or predictable, result.

Quiz your dentist about possible shortcomings.

If problem issues exist with your case, it doesn't mean that a clear aligner system absolutely can't or shouldn't be used for your treatment.

But it absolutely does mean that it's your dentist's obligation to advise you about likely disadvantages and problems, as well as possible treatment alternatives, so you can make an informed decision about the treatment you receive.

  • Acceptable vs. perfect results may make a reasonable trade-off. - After all factors and considerations have been weighed (convenience, time, cost, results), you may decide that removable aligner treatment still makes the best choice for you.

    And that's a reasonable choice to make, as long as you've been informed.

  • Possibly a removable aligner system should only be used for a portion of your treatment. - With this approach, more difficult/less predictable tooth movements are accomplished during a phase of wearing conventional braces.

    Then once your case has been transformed to a less involved malocclusion that's more suitable for Invisalign® treatment, it can be completed using it.

 

Problem issues and disadvantages associated with the Invisalign® system.


1) Invisalign® doesn't make the best choice for correcting all types of malocclusions.

In comparison to conventional (wire and brackets) braces, removable systems (like Invisalign®, ClearCorrect®, eCligner®, ClearPath®, Simpli 5®, etc...) don't offer your dentist the same level of detailed control over creating some types of tooth movements.

And due to this limitation, this technique has typically been thought of as best suited just for treating mild to moderately complex malocclusions.

Having said that, the speed of evolution of clear aligner technique always has been and continues to be dramatic, with methods of treating more and more complex cases continually being devised.

Slideshow detailing a case that would be difficult to treat with Invisalign®.

This case makes a poor, or at least very difficult, choice for routine Invisalign® treatment.

a) Examples of conditions that may be too involved for Invisalign® treatment.

Due to its diminished amount of control over tooth movements as compared to conventional braces, Invisalign® usually isn't considered the best choice for treating cases that involve:

  • Severely rotated teeth - Teeth rotated from their normal position by more than 20 degrees (especially premolars and lower eyeteeth).
  • Teeth that are severely tipped - Teeth angled more than 45 degrees from normal.
  • Large tooth spacings - Cases where all tooth gaps (combined) total more than 6 mm per arch. (6mm is roughly 1/4 inch.)
  • Crowded teeth - Cases where the amount of space needed to properly realign the teeth exceeds 6mm (per dental arch).
  • Other difficult situations - Severe deep overbites, skeletally based malocclusions and open bites (or other cases where the extrusion of teeth is required).

Phan 2007 [page references]

[Related page: Here's a comparison table that contains details about the types of cases that standard Invisalign® (vs. Invisalign Expresss®) is typically considered best suited for treating.]

2017 update on Invisalign® (and ClearCorrect®) treatment limitations.

As stated above, applications for clear aligner therapy are constantly expanding. And in fact, a discussion in a paper by Weir (2017) suggests that due to time requirements needed for data collection, its analysis and publication, what's found in published research typically lags the true current level of capabilities.

This same paper collected data from the companies that make the Invisalign® and ClearCorrect® systems and formulated a table that categorized types of orthodontic tooth movements in regard to being predictable, moderately predictable or difficult to achieve. (The parameters stated above would fall in the "predictable" category.)

In that table, we noticed that the cutoff points for tooth rotations differed considerably from what we show above. The Weir table (which we assume offers more current information) stated:

Predictable tooth rotations.
  • Incisors - Central incisors rotated from their normal position by up to 40 degrees. Lateral incisors up to 30 degrees.
  • Canines and Premolars - Up to 45 degree rotations.
  • Molars - Up to 20 degrees.

The Weir table also expounded on possibilities for tooth extrusion and intrusion. (The process of raising or lowering a tooth's position in the jawbone, so to level out the comparative height of teeth.)

These can be difficult movements to accomplish using plastic aligners because they have trouble delivering the needed level of forces to the teeth.

Predictable levels of tooth intrusion and extrusion.
  • Anteriors (front teeth) - 2.5 mm extrusions. 0.5 mm intrusions.
  • Posteriors (back teeth) - Extrusions are not possible. 0.5 mm intrusions.

Also listed in Weir the table but not mentioned in our list above:

Midline discrepancies.

Up to 2mm left or right of center (per arch). (A midline is the imaginary line that divides your teeth into left and right groups.)

b) You may need to wear attachments and buttons too.

As a way of overcoming some of its inherent limitations, treatment via the Invisalign® system often involves the use of "attachments," or "buttons" and elastics (use the link for more information and pictures).

  • On the upside, using them expands the range of cases that Invisalign® can be used to treat.
  • As a disadvantage however, these items may be visible to others as well as a nuisance to you. That means, when they're required you do get the benefit of wearing a removable orthodontic system but not so much one that's as "invisible" or unobtrusive as you might have anticipated.

Ask your dentist what will be needed for your case. It's possible that after all other pros and cons are considered and then compared to having traditional braces that the idea of using Invisalign® may hold less appeal.

c) More about the issue of closing large tooth spacings.

The limitation mentioned above about closing large spaces with Invisalign® may be an issue for your case even if your teeth are severely crowded.

That's because your treatment plan may involve the extraction of some teeth, as a way of creating space into which your remaining crowded teeth can be realigned. Here's an animation that shows how this technique is used. (Examples of how other basic orthodontic techniques are used with Invisalign® are illustrated too.)


2) Tooth issues that may interfere with having Invisalign® treatment.

With removable braces it's the fit of the plastic aligners that generates and directs the forces that straighten your teeth. And this means that any situation that interferes with creating an ideal aligner-to-tooth relationship may hamper the effectiveness, or predictability, of your treatment.

a) The shape of your teeth may impose limitations.

As an example, if the crowns of your teeth (the portion of each tooth that fits into the aligner) are especially short, Invisalign® probably isn't the best treatment choice for you.

Besides just short teeth, those that are pegged, round or severely tipped can be difficult for Invisalign® aligners to manipulate too.

b) Your teeth must be in good repair before your treatment is begun.

Any new or replacement dental restorations that must be placed while you're undergoing your Invisalign® treatment may alter the fit of your aligners. Because of this, any planned dental work should be placed either before or after, but not during, your treatment process.

Even having just one tooth fixed can mess things up.

Remember, the entire series of Invisalign® aligners that you'll wear is created before your treatment is begun.

And while a small dental restoration might easily be accommodated, a large one that significantly changes the shape of a tooth (and therefore interferes with the fit of your aligners) might cause a need for a "mid-course correction" (having a new set of records taken and new set of aligners made). There will probably be some expense involved with this.

c) Some types of existing dental work may interfere with Invisalign® treatment.

The Invisalign® system sometimes requires the use of "attachments" and "buttons" (discussed above). It can be difficult, or in some instances even impossible, to bond these items onto certain types of dental work (i.e. crowns, porcelain veneers).

As a separate issue, having dental bridges (a type of dental work that splints multiple teeth together as a unit) makes having Invisalign® treatment difficult, if not impossible.


3) Treatment with removable braces requires patient cooperation, and that can be a big disadvantage.

One of the main features that makes Invisalign® so attractive to patients is also one of its biggest weaknesses. That is, being able to take your aligners out.

a) With Invisalign® you're in control of the success of your treatment.

Being able to take your aligners out whenever you want is a great advantage for you, the patient, but it's a disadvantage for your dentist, the treatment provider.

Since no progress can be made unless your aligners are worn as prescribed (22 hours per day), your dentist must rely on your motivation and dependability for the success of your treatment.

That means the Invisalign® system is not the best choice for any individual where there's some question about their ability, or desire, to comply with their dentist's directions.

b) Noncompliance can cause big problems.

Patient noncompliance can cause all sorts of difficulties.

  • At a minimum, not wearing your aligners as directed will slow the progress of your treatment.
  • Worse, not wearing them for some period of time may allow your previous progress to relapse, or even allow your case to veer completely off-track.

c) Noncompliance can be expensive.

Once things have started to go wrong, your dentist may be able to get you back on-track by having you re-wear previous sets of aligners (aligners should never be discarded without your dentist's permission).

If this doesn't work however, your treatment will need some type of reset.

  • With Invisalign® this is termed a "mid-course correction."
  • Your dentist will need to repeat many of the initial steps of your treatment process so a new set of aligners can be made.
  • Some versions of the Invisalign® system include a free mid-course correction, if needed. But that is a courtesy and savings for your dentist, not you.

    If your dentist has to expend additional treatment time and materials (taking records and impressions), it's only logical that they should pass these expenses on to you. It may be several hundred dollars.

4) Conventional treatment approaches may cost less.

You'll probably find that your cost for Invisalign® is slightly more than for conventional braces (from the same provider). This isn't always the case, it may be the same. But it's unlikely that it will be less. Here's a page where we discuss treatment costs for different types of braces.

a) In some instances, choosing Invisalign® likely will cost you more.

If you're just seeking treatment for a minor orthodontic problem, thinking that Invisalign® (including Express®), or the competing system ClearCorrect®, are your only removable braces options may not be entirely accurate.

There are other choices available, some of which are "invisible" too. As a benefit of choosing one of them, you may find that it's cheaper.

A picture showing orthodontic case treatment using a Hawley appliance or Simpli 5®.

Minor corrections may be cheaper to correct using a traditional Hawley appliance or Simpli 5®.

b) Hawley appliances. / Simpli 5®.

Your dentist may be able to treat simple cases with either:

  • A standard removable Hawley-type appliance (plastic and wire construction).
  • An Invisalign®-like product such as Simpli 5®.

(These are the types of appliances dentists used for treating minor cases before Invisalign® came along.)

As an advantage, your dentist's overall cost when using either of these alternatives is likely to be less than what Invisalign®, or even Invisalign Express®, would cost them. As a result, they may be able to charge you less for treating your case.


5) Wearing Invisalign® can (theoretically) increase your risk for cavities.

One of the big advantages of removable tooth-aligner systems is that you can take them out to clean your teeth. But under certain circumstances, wearing them can place your teeth at increased risk for the formation of tooth decay.

What's the basis of this risk?

When you wear your aligners, your teeth are essentially encased in plastic. And this makes the environment immediately surrounding them separate and isolated (sealed off) from the rest of your mouth where normal biological anti-cavity events take place.

Under certain conditions (like when you don't keep your teeth and aligners clean, or follow directions regarding food and beverage consumption), conditions can form that place you at increased risk for tooth decay formation. (Use this link for details.)

Of course, this doesn't have to be the case. If you follow the rules you're given, you shouldn't have any problems. But for those who are lax in their habits, their risk for decay can be substantial. And this may be a good reason why Invisalign® might not make the best choice for them.


6) Other limitations and disadvantages associated with Invisalign®.

There can be other factors related to the use of removable braces that can present problems. They include:

  • The potential exists that your Invisalign® aligners will affect the way you speak (although this is usually quickly and easily overcome).
  • There have been isolated reports of what may be allergic reactions to the plastic that is used to make Invisalign® aligners.
  • Historically, there were age limitations associated with having standard Invisalign® treatment. This difficulty has since been remedied with the introduction of Invisalign Teen®.

It's your dentist's obligation to discuss all disadvantages and potential problems with you.

Your dentist is supposed to be your adviser.

Your dentist's role should be one where they simply evaluate your current status and then discuss with you the advantages and disadvantages of all of the various types of orthodontic approaches (traditional braces, lingual braces, Invisalign® and other types of removable orthodontic appliances) that are available to remedy it, whether they can personally provide this treatment or not.

Few general dentists can offer treatment alternatives.

As a consumer, you need to understand that for a lot of general dentists, clear aligner therapy (like Invisalign®, ClearCorrect®, eCligner®, ClearPath®, or Simpli 5®) is the only orthodontic technique that they have to offer for treating relatively involved cases. (Very few general dentists place conventional wire-and-brackets dental braces.)

That means that a general dentist usually can't offer treatment alternatives without losing (referring) the patient's case (such as to an orthodontist who can offer multiple treatment approaches). (More about dentist qualifications needed to practice clear aligner therapy.)

This can affect the dentist's financial bottom line, and might be motivation for them to go ahead and treat cases with removable braces when another technique might be expected to produce a superior, or more predictable, outcome and therefore be in the patient's better interest.

While most patients won't have the needed expertise to fully discuss this issue with their dentist, it's simple enough for anyone to just ask: Are there any reasons why clear aligner therapy shouldn't be my first choice for my treatment?"

 

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