The Seattle Insider’s Guide to Invisalign

Does Invisalign work?

Yes, but the answer is complicated. Invisalign is a product that is innovative and technically sophisticated with a certain aesthetic elegance, not unlike an iphone; therefore, many assume that Invisalign is similar to an iphone in that where it is acquired is unimportant. In reality, Invisalign is of greater similarity to a surgical robot or a Boeing aircraft—technically advanced, yet dependent upon the experience and judgment of the operator. However, given that Invisalign is a commercial product, developed and marketed directly to the public, and that the chance of morbidity is non-existent, the threshold of qualification to become an Invisalign provider has been loosely regulated. This is a complicating factor in Invisalign performance due to several issues. Firstly, the Invisalign technology has been marketed to both orthodontists and general dentists under the mistaken belief that the computer-programed Invisalign baseline is sufficiently sophisticated to produce satisfactory results in non-complex cases without significant doctor modification. This has not proven to be true. The Invisalign baseline considers only position of the dentition without reference to bone and soft tissue status and relationship, factors which greatly impact treatment planning and the sequencing of tooth movement. Secondly, the mechanics of the Invisalign system, i.e. the capacity for, and application of, force, are quite distinct from the edgewise/bracket-and-wire system; therefore, to effectively utilize Invisalign, the practitioner, whether orthodontist or general/aesthetic dentist, must make a significant educational investment in the use of this tool. Thirdly, a further complication for the non-orthodontist is that the ability to determine the relative complexity of an orthodontic case, as well as treatment plan for those that are complex, is developed not through education as a general/aesthetic dentist but through two to three years of post-doctorate education in orthodontics. (Even so, there do exist general/aesthetic practitioners who are capable of utilizing Invisalign responsibly and who are quick to refer those cases that present with complicating factors to an orthodontic specialist.)

The fact that the question remains, “Does Invisalign work?” points to the issues discussed above and the resulting inconsistency in treatment outcome. A significant number of Invisalign cases have been and are attempted by those who do not have the adequate diagnostic skills, mechanical understanding, and/or experience to complete these treatments. However, when utilized by an orthodontic clinician who is both experienced in the specific biomechanics associated with Invisalign treatment and who has the diagnostic ability to recognize appropriate clinical indications, Invisalign is a very effective and reliable orthodontic modality.

Does Invisalign only work in certain cases?

Invisalign aligners are one of several tools that an orthodontist may use to move teeth, as are traditional braces, with each tool having both advantages and disadvantages. Certain tooth movements are not accomplished effectively by Invisalign aligners. In such cases, these difficult movements may be accomplished using limited braces (often, on a few teeth for a brief period), resulting in a case that can then be successfully completed with Invisalign. By integrating modalities, experienced orthodontists are able to treat a wide variety of cases with Invisalign and achieve ideal results. (What are these movements? Due to the specific mechanical properties of the Invisalign appliance, which differ substantially from that of a wire and bracket appliance, the aligners are a poor choice for translating large rooted teeth and do not rotate teeth efficiently.)

Why use Invisalign?

Invisalign aligners are very thin, clear, removable, and intimately approximated to the teeth; they are extremely “aesthetic” compared to traditional or even clear braces. They are less costly, sometimes significantly so, than lingual braces (braces on the inner aspect of the teeth) and avoid the associated issues of speech impediment and discomfort to the tongue.

Are the advantages of Invisalign only cosmetic?

No. In certain cases the use of Invisalign presents a clinical advantage, such as 1) when enhanced control of teeth is required—Invisalign is quite effective in creating space of exact size, e.g. where precise widths are needed for post-orthodontic restorations; 2) when braces would not remain on the teeth well (e.g. patients with numerous crowns or veneers, patients with abnormal tooth enamel); 3) when access for particular dental procedures is important; 4) when indications of root resorption necessitate the isolation of certain teeth: Invisalign is able to accomplish this whereas braces cannot do so; 5) when there exists an anterior open bite in which the patient cannot bite the front teeth together (i.e. to incise lettuce); and 6) when there exists a deep bite in which there is excessive vertical overlap of the upper and lower incisors.

Does Invisalign cost more than braces?

Fees structures vary across the country. In some regions, such as our own, Invisalign is priced similarly to fixed appliance/traditional treatment.

Does Invisalign treatment take longer than braces?

No, if the doctor is experienced in orthodontic treatment and Invisalign specifically, most Invisalign cases are somewhat shorter in duration than if they had been attempted with fixed appliances (braces). Cases that include movements difficult for Invisalign to accomplish, thus necessitating limited fixed appliances in a hybrid Invisalign/fixed appliance treatment, experience an overall duration similar to that of fixed appliance treatment. Certain types of cases, however, are best treated with fixed appliance alone.

What is involved in initiating Invisalign treatment? Each patient, regardless of treatment type, should receive a comprehensive examination of his or her facial structures (hard and soft tissue), teeth and dental alignment, jaw joint (temporomandibular joint), periodontal structures (hard and soft tissue), and a meaningful discussion covering his or her goals for treatment and other salient issues. Invisalign patients will have diagnostic records taken including a digital intraoral scan (which will later be used to create aligners). These records are sent to Aligntech (the parent company of Invisalign) with an initial prescription provided by the orthodontist. The Aligntech technicians use software to formulate a preliminary treatment plan involving a “path” toward the prescription of desired tooth alignment. This preliminary treatment plan will indicate intermediate alignments (stages), each slightly different (from misaligned to ideally aligned). The number of stages will vary depending upon the extent of tooth movement required. The software used for this preliminary treatment plan cannot, however, determine what is clinically realistic or advisable; therefore, it is imperative that this treatment plan be modified by an orthodontist who is experienced in both diagnostics and Invisalign biomechanics. (The preliminary treatment plan would commonly lead to case failure if implemented without modification: this is why I recommend that Invisalign treatment be sought from a qualified practitioner [see “Does Invisalign Work?” above].) Once the orthodontist has sufficiently modified the treatment plan for the case in question, he or she will approve the plan (known as a Clincheck) and the construction of aligners will commence. In our Seattle office, the aligners arrive two to three weeks after the taking of diagnostic records.

What happens when I receive the Invisalign aligners?

At the first appointment, the aligners will be checked to confirm fit and you will be instructed on their placement and removal. The rate of change from one aligner to the next will also be discussed. Two cases will be provided and you will be asked to store all of your used aligners in their individual packages in the case any should be needed in the future. You will also be shown how to clean the aligners and given tips to help you incorporate the aligners into your everyday life. This is an exciting and relatively short appointment.

What will I notice once I begin wearing the aligners?

First, you may be surprised at how difficult it is to see the aligners once on and how closely they fit to the teeth (the fit will become even closer as your teeth adjust to the aligners). You will probably note a mild increase in salivation because your mouth senses something new and assumes it is food; this phenomenon usually lasts one to two days. As you speak while wearing the aligners, we advise that attention be brought to any changes in your speech; if such changes occur, we recommend practicing those sounds that require adaptation. Speech adaptation usually takes one to two days, as well.

Is Invisalign treatment painful?

The perception of discomfort or pain varies widely among individuals, but, given that orthodontic tooth movement requires some amount of force to elicit a biological response, at least some initial discomfort will be experienced. Invisalign aligners, however, cannot generate the heavy force of the traditional braces of past generations. Patients who are seeking retreatment with Invisalign tend to report less discomfort as compared to earlier, traditional treatment. However, there is likely to be an initial period of low-level discomfort around the teeth when the dentition goes from unperturbed to orthodontically mobile. Once the Invisalign orthodontic process begins, however, this discomfort lessens.

How many hours per day are the Invisalign aligners to be worn?

The ideal amount is 22+ hours per day. Typically, patients remove the aligners to eat, clean their teeth, clean the aligners, and to speak or perform in special situations. They should be worn at all other times, including sleep. It is ideal to reduce the number of times the aligners are removed each day; we have strategies for those who like to snack or sip throughout the day.

Does Invisalign treatment involve anything that is attached to your teeth?

At some point in treatment, most patients are provided with small, tooth-colored attachments that have very specific shapes and are positioned precisely at certain spots on designated teeth. These attachments will correspond to similarly shaped forms in the aligners to allow specific force vectors to be delivered to each tooth to bring about precise patterns of orchestrated tooth movements through space and time. In addition, auxillaries such as bonded buttons or hooks may be used in concert with the aligners to allow the use of other force-generating units, such as elastics.

What if I have a nightguard/biteplate?

Your nightguard/biteplate will not fit your teeth as they begin to move. Therefore, you will be asked to wear the aligners at night. The aligners (which cover the chewing surfaces of the teeth) will serve as a new nightguard/biteplate. Because each set of aligners is typically worn for only two weeks, even vigorous tooth grinders will not wear through the material.

What if I have crowns, bonding, or veneers?

In general, Invisalign is better suited for those patients with significant dental work of this type because these restorations present a more difficult bonding surface than the natural tooth, whereas Invisalign aligners work equally well with restored and unrestored teeth.

What if I have bridges or implants?

If fixed teeth exist, such as implants or ankylosed teeth (teeth that have fused to the bone, usually after trauma), these teeth must be considered in the overall treatment plan whether that treatment involves Invisalign or braces. If, in the final result, these teeth can remain in the present position, they can be extremely helpful “anchors” from which to move other teeth. If these teeth would ideally be repositioned, the decision must be made whether or not to do so. In the case of bridges that need repositioning, the abutment teeth can be moved individually after the pontic(s) are removed. (Pontics are the false teeth that connect the abutment teeth.)

Should I have a dental check-up before Invisalign?

Yes. It is important that dental issues such as decay, gum disease, infection, tartar build-up or any procedure that would necessitate altering the shape of any tooth be completed before your aligners are fabricated. A very intimate fit of the aligners results in the most efficient and effective transfer of orthodontic forces and, therefore, the most ideal orthodontic result. In addition, the dental check-up allows your dentist and orthodontist to collaborate in planning your overall long-term treatment relative to aesthetics, function, and health.

Can I wear the aligners just at night for more weeks and get an ideal result?

No. The orthodontic process is a biologic reaction to the presence of force; therefore, when the stimulus of force is removed, aspects of the biologic (and orthodontic) process begin to reverse. To complicate matters, different teeth will move and revert at different rates. This means that each tooth will shift to a different stage in treatment and no single aligner will fit all of the teeth as well as it should. If this “non-tracking” is caught early on, extremely consistent wear of the best-fitting aligner can recapture the dentition. If the situation has gone too far, rescanning is necessary to create a new treatment plan and set of aligners; this lengthens treatment and, at some point, an additional fee will be charged by Aligntech and the orthodontic office. The best advice is to commit to the recommended level of aligner wear—22+ hours per day. (If this seems unlikely, a viable alternative is to consider the use of clear brackets and enamel-colored wire. The convenience of such a choice includes having no loose parts to misplace and ease of maintenance [the appliance itself is cleaned when brushing the teeth and is not removed and repositioned, necessitating brushing, upon eating]. Once the initial period of adjustment has occurred, this appliance protocol is typically found to be very satisfactory.)

Is Invisalign for adults only?

No. In fact, teenagers often make the best patients. The biologic facts that, compared with adults, teens have more active bone metabolism, more facial growth, and active tooth eruption means that their dentition is quite malleable. This makes the teenager an excellent candidate for Invisalign (except in such cases that Invisalign is not diagnostically recommended). In assessing the appropriateness of Invisalign for a teen, one must consider both the orthodontic situation and the patient’s level of dedication and commitment to achieving treatment goals. Many teens are highly motivated, responsible, and willing. For this type of teen, Invisalign is not only more aesthetic and convenient, it allows for better oral hygiene and less interference with daily activities (e.g. athletics, playing certain musical instruments, eating specific foods) and usually a shorter treatment length. For the peace of mind of parents, in our practice it is made clear to the teen that we are committed and obligated to the best orthodontic result possible. Therefore, if aligner wear is insufficient, the treatment will revert to traditional braces (at no extra cost to the parents). While this type of motivation is not needed for the adult patient, it can be very helpful in solidifying the teen’s commitment to consistent wear and hygiene.