Tech tip: Why aren't the posterior teeth in occlusion?

Question:

As my patient’s treatment nears its end, I’m noticing that the upper & lower anterior teeth are touching when the patient bites down, but the posterior teeth are not in occlusion. What’s going on?

Answer:

There are many possible causes of this situation. This phenomenon is fairly common with clear aligners, and it’s usually temporary. It can be caused by the “hinging” action of the jaw.

Imagine placing a 1 mm sheet of flat plastic over the occlusal & incisal surfaces of the lower teeth. As the jaw closes, the posterior teeth will contact first. The patient would have to bite down firmly to get the anterior teeth to touch completely.

The same thing can happen when the teeth are covered by clear aligners. When the patient first starts wearing them, the posterior teeth are the first to contact. After wearing the aligners for a while, the teeth adjust to compensate, and before long, the patient can bite evenly with the aligners on.

The posterior teeth will usually intrude slightly to make room for the aligner, as the patient clinches his or her jaw throughout the day. Once the teeth have adjusted to the aligners, if the patient removes the aligners and bites down, the anterior teeth will make contact first and the posterior teeth probably won't quite touch.

This is not typically a big concern, however, because the posterior teeth will usually super-erupt back into normal occlusion as soon as they get a chance. After the patient has worn the final retainer for 3-6 months and the teeth are stable, the patient can switch to wearing the retainer on alternate days to give the posterior teeth freedom to move back into their normal position. Another option is to prescribe a Hawley retainer which won't interfere with occlusion, allowing the posterior teeth to super-erupt freely.

Tech tip: 4 ways to correct crowding

Question:

Which techniques should I prescribe to treat crowding?

Answer:

The simplest option is to check “only if needed” and allow our dental technicians to offer their recommendations.

If you have specific preferences for a patient's treatment, though, please let us know. At ClearCorrect, doctors are in charge. We will customize the clear aligners to carry out whatever treatment you prescribe to the best of our ability. If you don't see an option on the form, feel free to provide special instructions in the “other instructions” section.;

For patients with severe crowding, it's usually best to use a combination of techniques. For instance, proclination and expansion are more predictable together than either technique alone.

If the crowding is not too severe, however, you may be able to achieve your goals with just one of the four options (procline, expand, distalize, or IPR).

Here are the four main techniques, and when we recommend using each one:

Procline

Patient with line drawn from nose to chin
A good candidate for proclination

Proclining teeth is a useful way to give a patient fuller lips or a fuller side profile. This is recommended for older patients whose lips are a little “droopy.” This can also be desirable for people who have a flat profile.

To check if a patient needs to be proclined, draw a line from the tip of the nose to the tip of the chin on a non-smiling profile picture. In an ideal profile, the upper lip should almost touch the line and the lower lip should overlap it slightly.

If both lips are well behind the line, the patient might benefit from proclination. If both lips are well past the line, lingualizing the teeth might improve the patient's profile. (Lingualization isn't one of the standard options, but you can request it in the “other instructions” section.)

Expand

Julia Roberts
A nice wide smile

Expansion is the most common method we use to create space. It should be used when there is visible space between the posterior teeth and the cheeks when the patient smiles. A wider smile that shows more teeth can help your patients “light up the room.” Think Julia Roberts or Anne Hathaway.

Distalize

We often recommend distalizing the anterior teeth and/or premolars 1-3 mm if you want to achieve a Class I bite and improve the patient's chewing function. We don't recommend distalizing molars; they're very difficult to translate. Distalizing and mesializing less than 4 mm per quadrant keeps the movements more predictable and reduces the chance of interference with other teeth. Of course, if you want to try for more than 4 mm, you can always request that in the “other instructions” section.

IPR

We like to avoid IPR (interproximal reduction) whenever possible. However, IPR is sometimes necessary to create space for very crowded teeth to move. IPR can also be used to treat a case quickly by keeping the teeth in their current positions and just rotating them into alignment.

We usually recommend IPR when we are aligning both arches and we need to reduce the width of the teeth on one arch to get proper overjet. In this situation, IPR is usually only needed on one arch.

We can also use IPR to put premolars or canines into a Class I relationship, or to correct a midline misalignment.

As providers treat more patients, they usually get a feel for which techniques work best for them. If you have any comments, or preferred techniques and tips, please share them in the comments.

Tech tip: Redesigned, simpler forms

We've recently redesigned all of our forms to be easier to understand and faster to fill out. If you’re a ClearCorrect provider, you’ll probably want to download these new forms from ClearComm and start using them right away.

Here's a quick comparison:

Comparison of old & new ClearCorrect forms

The default options for most common cases are now highlighted in green, so you can write your prescriptions more quickly. We've also organized the case submission form into three clear sections and simplified the wording of our treatment options. You still have just as much flexibility in how you prescribe your treatment, but hopefully now it will be more clear how to do it.

Instead of a confusing case revision form, we now have separate forms for midcourse corrections, refinements, and for the rare post-approval setup revision. The quality control form has been discontinued (just talk to your account rep if you experience any issues), and we have an IPR tracking chart you can use to keep track of your patients’ IPR. Also, by popular demand, we have an optional FMX template to go along with our optional photo template.

You can get all the new forms on ClearComm at dr.clearcorrect.com. We’ve also moved our logos, images, and promotional items from our main site to ClearComm in preparation for adding more provider-exclusive content.

If you don't know your username or password for ClearComm, your account rep can help you with that. Just give us a call at (888) 331-3323 or email customerservice@clearcorrect.com. And let us know what you think of the new forms. We're always open to suggestions.

Tech tip: 3 impression tips that can save you weeks

We recently determined that 3 basic issues are accounting for over 75% of all the bad impressions that we receive. Here are the issues, and how to correct them.

Most frequent impression problems: 1) Double impression, 2) Material not fully set, 3) Posterior distortion, 4) Relining/reinserting, 5) Tray too small, 6) No light body, 7) Not enough material, 8) Missing opposing impression, 9) Material lifter off of tray

Issue #1: Double impression in 2-step material

The most common problem that we find is a double impression, which usually happens during a 2-step impression.

The easiest solution is to switch to a simpler, more reliable 1-step impression material, such as Sultan Genie VPS. We've prepared a video and a printed guide for this type of material.

If you prefer the 2-step impression process, that's okay too. Just keep an eye out for double impressions. Remember to cover the putty with a plastic sheet when you take the first impression, and to take your second impression before the first one has fully set. We have a video and printed guide for this type of impression as well.

Issue #2: Material not fully set

Our second-most common issue is material that hasn't fully set before being removed. There are two simple things you can do to prevent this problem:

  1. Set a timer and make sure to follow the directions for your material exactly.
  2. Discard the first 1 inch of material that comes out of every new mixing tip.

Issue #3: Posterior distortion

The final big issue is distortion of the most distal teeth in the impression. It can be hard to see back there, and sometimes the posterior teeth get shortchanged. There are a couple of ways to avoid this problem:

  1. Make sure that you're using a correctly-sized tray. It should extend past the last tooth in the arch without touching the gums.
  2. Before inserting the tray containing light body, add some light body directly to the occlusal and distal portion of the last tooth in the arch, ensuring that the last tooth is completely covered with material.

We hope this helps. Look for these issues before you send your impressions in, and you could save yourself & your patient the hassle of taking new impressions.