Getting Started With Invisalign

How many patients are being given the option of laminates to fix minor tooth problems when they would better benefit from orthodontics? I feel more comfortable doing minor tooth movement with ortho than laminates.

It is said that if you only have a hammer, everything looks like a nail. That certainly is true in cosmetic dentistry.

By Jean Furuyama, DDS, FAGD, FADI

How many patients are being given the option of laminates to fix minor tooth problems when they would better benefit from orthodontics? I feel more comfortable doing minor tooth movement with ortho than laminates. True, I have been doing fixed ortho for more than 20 years and look at things differently than someone who has never been trained in ortho. But I think we owe it to our patients to offer alternatives that will give them the cosmetic results they want and the dentistry they deserve without destroying their natural teeth.

One of the easiest ways to get started in ortho is to take the Invisalign certification course. You will learn which cases are good candidates for Invisalign and which to avoid. Once you are certified and submit cases, their technical support reps will help you through the process, the most important of which is the treatment-planning stage.

The simplest cases are the ones in which you have good arch development but tooth-sized discrepancies that create in and out malalignments. One way to decide whether to refer the case or not is to look at the posterior occlusion. If the bite is good and the crowding is only in the anterior region, it is usually an excellent candidate for Invisalign. Then look at the profile of the patient. Is this a bimax protrusion case? Or a severe overbite? These cases probably should be referred to a specialist.

Other cases that are not good candidates for Invisalign are open bites. Open bites are difficult with fixed ortho and nearly impossible with aligners. Unlike fixed ortho, where extrusion is the simplest movement, extrusion is a difficult movement with Invisalign.

Invisalign is also not very good with severely tipped teeth such as molars that have moved mesially into extraction spaces. These cases are usually handled better with fixed sectional braces to upright the molars enough to get the aligners on. Once the tipping is corrected, the aligners can finish the uprighting, but you have to be able to get the aligners to seat in order to do this.

Other cases that you should probably avoid in the beginning are spacing problems resulting from severe tongue thrusts. Because most Invisalign candidates are adults whose habits are ingrained, it is difficult to maintain space closures unless the patient is committed to permanent retention. Even with lingual fixed retainers, which I recommend at the completion of almost all spacing cases, the tongue will eventually push the teeth forward and the spaces will move distally. This must be explained to the patient before you start treatment.

Other cases that you should probably stay away from are skeletal malocclusions. I see a lot of Class III patients in my practice because I treat a lot of Asians. My experience has been that upper expansion and reverse headgear seem to give better results. One way to tell if you should attempt treatment is to have the patient close slowly and stop just before going into full closure. If the teeth are almost in Class I and the profile is OK, go ahead and treat because this is a pseudo Class III. If in doubt, refer.

Other cases that are not suitable for Invisalign are children who don’t have their second molars in yet. Even if they have their second molars in, watch particularly for teenage boys. Compliance is an issue with any removable appliance, and if the patient is doing it to please his mother, you’re not going to get the cooperation you need. Trust me on this one.

So what cases are good candidates? Obviously, minor tooth movement. Post-ortho relapse of the upper teeth are easier than relapse of the lower anteriors. I usually explain to patients that we can do most of the treatment with Invisalign, but particularly lower anteriors might need a short fixed treatment of three to five months to accomplish the root torquing. For some reason, lower anteriors being such small teeth sometimes do not fully derotate as anticipated. Usually, we can accomplish the rotations using auxilliaries with the Invisalign, but sometimes it is faster and easier to do it with fixed sectionals.

Intrusions are easily accomplished with Invisalign. I always had a difficult time intruding molars that had extruded into extraction spaces. With Invisalign, this is a fairly easy movement and is helpful for preprosthetic treatment.

In summary, lingual-labial movements are the easiest movements with Invisalign. Rotations and extrusions are the most difficult. Remember this when doing treatment planning and explain it to patients.

Also explain that their home care has to be exceptionally good. I tell patients that unless they are willing to commit to brushing and flossing each time after they eat, I won’t take the case. I explain to them that the aligners cover the teeth so that the saliva, which is nature’s self-cleaning mechanism, can’t get in to clean. I also tell them that the aligners must be worn 24 hours a day and taken out only when eating. To wear them less will result in jiggling teeth and patients will end up with loose teeth and poor results. In addition, all cavities must be fixed before starting treatment because the impression we send to Align is scanned and all the aligners are made from that one impression. If fillings are done during treatment, the shapes of the teeth might change slightly and the rest of the aligners might not fit.

During this consult meeting, I also go over the financials with the patient. The total cost is $6,000 to $7,000, but if I quote that I will get more sticker-shock resistance than if I tell them that the records (photos, ceph, and study models) are $385 and the down payment is $2,500 when we take the final impressions and send the case to Align. I also tell them that they will come in every six weeks and pay $300 each time until the total is paid in full, which is $6,000 to $7,000 depending on the number of aligners required to complete the case. I also offer Care Credit if they need to extend payments.

Once the patient has committed to treatment, nearly flawless polyvinyl impressions must be taken, which is one of the hardest things about Invisalign. It’s hard enough to take a flawless impression of one prepped tooth, let alone a full arch. After trying all sorts of combinations of taking these impressions, I have come up with a method that works almost every time. First, I take a preliminary impression with a piece of plastic such as barrier material, which envelopes the tray and the polyvinyl material. The plastic keeps the material from going down the throat of the patient and leaves all kinds of nooks for the wash material to grip. My staff takes this preliminary impression, and I take the final impression.

Meanwhile, as my assistant uses gauze to dry all the teeth (this is critical to get a good impression), I load the tray with the light-bodied wash and signal her to remove the gauze. I immediately place the tray and hold it in place for the entire two minutes on the upper or have the patient bite down to hold it in place on the lower. Don’t try to have the patient bite down on the upper or you most likely will miss the anterior teeth in the impression. Inspect the impression for voids and pulls because Align will reject it if it’s not perfect, and it will waste your patient’s and your time to retake the impressions.

After a couple of weeks, you will get the Clincheck back via the Internet. Don’t simply accept what the technician designs. Be sure that they follow your instructions and give you what you want. They are not mind readers, and you need to be clear about your objectives. Always read the comments section first, then the interproximal reduction guidelines. I hate doing IPR of only 0.2 to 0.3 millimeters because that means doing it manually with polishing strips. It takes forever and patients hate it, especially when they start bleeding at the gum line, which is hard to avoid. I prefer to do 0.4 to 0.5 millimeters on the distals of the canines and in the premolar and molar regions when possible. I can do it easily with high-speed and tiny needlenosed burs. I also like to avoid IPR on anteriors because patients get nervous about that - much more than if all the IPR is on the posterior teeth.

Another thing I often have to specify for the Clincheck is that if more aligners are needed on one arch than the other, it is easier to start the arch that takes the longest first so that the aligners end together. Otherwise I end up with aligners breaking before I am ready to order the retainers for both arches. And sometimes at the end of treatment I need to do more corrections, so I have to pay for additional retainers if the additional movement involves the finished arch.

Once you OK the Clincheck, it usually takes another couple of weeks to have all the aligners manufactured at their facility in Costa Rica. You will receive the entire shipment of all the aligners and then may call the patient to start treatment.

Because the aligners are usually very tight and patients have a hard time taking them off in the first four days or so, we usually just give patients the aligners, go over the home care instructions with them, and give them a plastic tool to help take off the aligners. We make sure patients understand that the tightness is necessary to get the teeth to move. We instruct them to place the aligners starting with the anterior teeth and pushing them down with their fingers on the posteriors, never biting them into place as this could break the aligners. If IPR is indicated before the first aligner, we do it now.

Then we schedule the patient to come back in two weeks, when we place the attachments. By this time he or she is able to place and remove the aligners and can cope with the additional difficulties that the attachments pose. Here are some hints on easy attachment placement:

  • Make a small hole with a pointed diamond in the center of the attachment template so excess composite can extrude out.
  • Use lip retractors (the ones you use for bleaching are great) so you can place the attachments on the entire arch at once.
  • Load the tooth-colored composite into the wells in the attachment template until the wells are just full, but not overloaded.
  • Etch teeth, bond with resin, light cure the bonding agent, then place the template tray on the arch and light cure each attachment well. <
  • Before removing the tray, take the diamond you used to make the hole and grind off any extruded composite that came through the hole so that it is flush with the rest of the attachment.
  • Remove the template and carefully remove any excess composite that may have flowed around the attachment.

The patient is now given aligners Nos. 2, 3, and 4 and rescheduled as a five-minute side book in six weeks. The IPR schedule page is attached to the inside of the chart so we don’t overlook doing the IPR at the correct times. If you forget, the teeth will not have room to move and will end up intruding. Any time you see a small space between the incisal of the tooth and the aligner, suspect that there is need to make more room. Once intruded, it is difficult to get these teeth down without using auxiliaries.

If we see a situation like this developing, we give the patient Chewies and instruct him or her to bite down as often as possible in that area. As he or she bites, the aligner moves gingivally and when it rebounds, the tight fit tends to pull the tooth down with it. If after six weeks of using the Chewies the tooth does not move down, we place a tooth-colored button on the facial and a metal button on the lingual. The aligners are cut to make space for the buttons. The patient then puts the aligner on and places one-sixteenth-inch elastics from the buccal to the lingual over the aligner to pull the tooth into place.

By learning just a few of these auxiliary techniques, you will find that Invisalign can be a valuable tool in your dental box. Patients love it because it is painless, effective, and gives them the smiles they always wanted but were unwilling to achieve if it meant fixed braces. You will love it because it takes so little chairside time, is easier and faster than conventinal orthodontics, and, most of all, generates so much patient satisfaction. It gives patients the option of a solution that preserves tooth structure and enhances their smiles. What more could you ask for?

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