Tech Tip: FAQ about Engagers

We sent out a survey recently asking doctors for their questions about engagers.

In this week’s tip, we’ve consulted with our Chief Technology Officer, Dr. James Mah, to get answers to your questions.

DrMah.jpegDr. Mah comments on engagers

Engagers are an active area of research and development at ClearCorrect and elsewhere.

Many conceptual designs for engagers have been discussed in literature and professional forums, but when they are reduced to practice and the shape is thermoformed in the engager template, problems of adaptation and air gaps reduce the capability of many of these designs.

Without conclusive information and until the mentioned adaptation problems are resolved, ClearCorrect is happy to stick to simple horizontal and vertical engagers, which work well.

Engagers and the treatment setup

When we send you a treatment setup, we are presenting our best attempt to represent the course of treatment that you want to pursue for your patient—the recommendations shown are not absolute. It’s up to you to make any necessary changes to create a custom plan for treating each individual patient.

Engager preferences and timing can be discussed and adjusted according to what you want for your patient. Just let us know about your particular preferences when you submit your case or when approving the treatment setup.

Engager.png

Engagers, templates & case revisions

On the treatment setup, if the engager is blue, it means it’s a new engager placement. If the engager is gray, it means it’s a previously placed engager.

engagers_placed_2.pngengagers_placed.png

If you are submitting a case revision based on a prior step (not new impressions or scans), we’ll assume that the existing engagers are still on the teeth. You won’t receive a new engager template unless new engagers are needed.

General questions about engagers

Do you need engagers, or can the case be done without them? Are they necessary to use if prescribed?

Much depends on case by case variables such as tooth morphology and the type of tooth movement. To simplify these decisions, ClearCorrect has provided guidelines on which teeth and types of tooth movements that we would recommend engagers.

These guidelines are general and are for you only to use and apply to individual patients. Variables such as clinical crown height (shorter or longer), tooth morphology (shape), root morphology and positions need to be considered.

It is the doctor that prescribes the engagers. The technician only provides a recommendation. If engagers are recommended, there is a valid reason to use them.

That being said, it is possible to treat some patients without engagers. ClearCorrect has designed the aligners to be more retentive to often eliminate the need for engagers. In addition, overcorrection of specific tooth movements also helps to reduce the need for engagers.

If an engager is lost DURING treatment, should I use the tray currently in use as the engager template?

Yes, the current aligner will generally have the best fit. In addition, since it has been worn, the composite should easily release from the engager void.

Can you make the engagers bigger with a square or triangle shape to give more control?

ClearCorrect has ongoing research to continually improve engagers. The evidence does not support the need for larger engagers. Additionally, this would introduce other problems related to placement on smaller clinical crowns, occlusal interferences and esthetics.

What should I do if the teeth are very crowded? I find that it is difficult to adapt the engager template and place engagers when this is the case.

Treatment of severe malocclusion often requires expansion/IPR and some improvement of tooth positions to allow for ease of engager placement. Doctors can prescribe engagers for later in treatment when submitting the case or when approving the treatment setup.

Engagers wear down over time and end up needing to be replaced. Is there anything I can do to avoid this?

This can depend on the type of material being used for the engager. In general, a filled resin will be more wear resistant than one that is unfilled.

Is there a way for you to incorporate more than one engager on a tooth to aid in rotation or extrusion? At times, I think this would be helpful.

While this may seem to help with rotations, it causes other problems in removal of the aligners. Researchers have tested this hypothesis and found that the teeth became excessively loose and when the aligner was being removed and inserted – it produced excessive force on the teeth.

Questions about composite material or flash

What is the best material (both composite and bond) to use for engagers? Microfill? Flowable? Hybrid?

In general, a flowable composite is used, but much depends on doctor preference and wear factors. A patient with heavy occlusion will likely require a filled or hybrid material that is more resistant to wear.

What are the best methods to place them without overfilling? I’d like to know the precise way to place the composite into the template while avoiding an over or under abundance.

See our article on how to place engagers. Clinicians generally develop an eye for the appropriate amount of material to place in the engager void.

Some clinicians prefer to puncture the engager void on the labial side with an explorer to create a vent and allow release of excess material before light curing.

How do you deal with flash? Should I remove the excess composite that flows on the facial surface?

Excess flash is generally removed with a multi-fluted carbide burr. Yes, the excess should be removed as it may lift the aligner slightly and this may affect the fit and tracking of the aligner.

What do I do about having too much or too little flash or bubbles at enamel resin interface? Is there a way to get it just right?

These are both signs of problems with filling the engager void with too little or too much resin. See our article on how to place engagers for recommendation on how to install.

Questions about attaching engagers

I have difficulty with the engagers staying on the tooth when using the template. They tend to pop off, are a pain when attaching for the first time and not always successful. Do you have any suggestions?

There could be a variety of technical issues such as under/over etching, excessive primer, and inadequate material in the engager void. You can check for any of these issues and address accordingly.

How do you ensure that the position of the engager using the template matches the engager in the aligner?

The best way to do this is to make sure that the template is fully seated.

It can be difficult to remove the template especially when placing multiple engagers and when bonding each side of the arch separately. What should I do about this?

Application of Vaseline usually helps to release the engager from the template.

When attaching an engager to a decalcified tooth, the composite does not stay on the tooth. Do you have any suggestions?

This is a complication of bonding to decalcified surfaces. It will not be possible to bond to severe decalcification. Glass ionomer materials may help.

I have trouble attaching engagers when teeth are lingual. Is there a trick to doing this?

Treatment of severe malocclusion often requires expansion/IPR and some improvement of tooth positions before placing engagers, to allow for ease of placement. Doctors can prescribe engagers later in treatment, when submitting the case or when approving thetreatment setup. You want to stage the treatment setup to start correcting the teeth from their lingual positions and place engagers later.

Questions about removing engagers

What is the best/easiest way to remove engagers? I have completely drilled off and attempted to remove with hand instruments.

A multi-fluted carbide burr is generally best.

It’s hard to see when you have removed the majority of the engager. Do you have any suggestions for making sure the entire engager is removed?

This is the same problem in restorative dentistry when an existing composite restoration is removed. Use of a metal instrument will show which areas have composite resin remaining. Some clinicians use a common pencil to help identify resin fragments.

How do you ensure you don’t remove any enamel when removing buttons?

A bond/bracket removing plier is recommended.

Questions about engager shape and size

On two max canine, is it possible for one engager to be thicker than the other?

This is most likely caused by differing amounts of composite resin placed in the engager voids.

The shape is too rounded. What about engagers with sharper corners?

ClearCorrect has ongoing research to continually improve engagers.

Some of the designed engagers prevent removing aligners. Is it possible to have a different design or to apply them later?

Treatment of severe malocclusion often requires expansion/IPR and some improvement of tooth positions before placing engagers, to allow for ease of placement. Doctors can prescribe engagers later in treatment, when submitting the case or when approving the treatment setup.

Questions on engagers and tracking/fitting issues

Sometimes they don’t fit. The previous aligner will fit perfect but the next one, or new one, won’t. What should I do about this?

Review the last fitting aligner. There may be tracking issues that have gone unnoticed until the next aligner. If tracking issues are present, have the patient stay with their current aligner, or you can request a revision.

Sometimes the engagers do not line up properly with the aligner even immediately after placing them. It seems like a problem with the fit of the template. Would it be best to maybe place engagers first before trying to move any teeth at all, like before step 1?

There may have been tracking issues prior to placing the engagers. It is possible to have the patient wear the next aligner without the engagers and return at the next visit and use the aligner as the engager template instead of the provided template.

Could the shape of the engager be enhanced to encourage continued seating of an engager when teeth aren’t tracking (extruding)?

This would be difficult to do. Teeth are being moved in fractions of a millimeter or 1-2 degrees of rotation. Another approach could be the use of a thermoforming plier to place divots or pressure points (aka dimples) at specific sites of the aligner.

The teeth sometimes have trouble tracking and end up not engaging after a while and the case ends up needing a revision. This is frustrating. What can I do about this?

Refinements/revisions are common with clear aligner treatment. There are numerous scientific articles on the efficiency and accuracy of tooth movements with aligners. The need for revisions increases with the complexity of the malocclusion.

Sometimes rotated teeth don’t track in the engagers, why is this and what can I do?

Much depends on the tooth, root length and root morphology. Be careful not to advance too quickly through the aligners. If necessary, you can extend the patient’s wear schedule to get the needed movements.

I rarely have engager cases that track adequately. What could be the reason for this?

Engagers are usually recommended for more difficult movements, so it's not surprising that those movements may be more prone to tracking issues. Patient non-compliance or advancing through the aligners too rapidly can cause cases to go off-track. Use of Chewies can help to reduce tracking issues.

 

We hope you found this information helpful! There's lots more where this came from—check out our Help Center, which is filled with useful information for treating your patients with clear aligners.

Also, don't miss our advanced training series of webinars on various topics related to clear aligner treatment.

Until next time…

ClearCorrect: Essential to My Digital Workflow

Dr. Meena Barsoum recently talked with Dental Product Shopper (DPS) about his experience using ClearCorrect--a more streamlined approach to clear aligner treatment processes. "The big driver for me personally is the ability to submit digital scans. Not only am I able to submit a more accurate impression for the ClearCorrect prescription, but the process is just that much easier for my patients and me," says Dr. Barsoum.

After consulting with his patient about clear aligner therapy, he is able to take a full mouth digital scan, and then submit the scan to the ClearCorrect online doctor portal within minutes. This quick turnaround time is huge for his practice and patients. He is able to quickly show the patient what their smile will look like at the end of treatment and walk them through all of the treatment steps. 

ClearCorrect's customized treatment setup plan (example below) allows doctors to review the digital representation of the complete course of treatment. The treatment setup contains 3D models for each step of the treatment, representing the tooth movements that the doctor prescribes. Once the doctor and patient approve the treatment setup, the models will be printed and used to manufacture clear aligners which are then delivered 2 to 3 weeks later.

 

"Making ClearCorrect a part of my practice has been very simple with convenient access to free online training covering advanced and basic aligner treatment topics. In addition, the online portal for submitting cases, making changes, and requesting retainers is easy to use. Also I have a dedicated account manager, and this available communication and support is a big benefit of working with ClearCorrect," continued Dr. Barsoum. 

Read the Dental Product Shopper full article here. 

Now offering ContacEZ IPR Strips & Snap-On Disc Guards

It's our pleasure to announce a new addition to our online store: ContacEZ IPR Strips and Snap-on Disc Guard. 

Pre-order these new items and save 10%. Enter promo code: PRESALE when ordering. Pre-order prices are for the ContacEZ IPR Strips and Snap-On Disc Guard only and are available until May 3rd.

10.png

We're happy to offer both of ContacEZ's IPR strip systems in three convenient packages.

IPR Strip System Package

These strips help to make IPR safe and more accurate without creating sharp corners. The strips curve and flex along the natural contours of the teeth to prevent soft tissue irritation, helping to avoid cutting excessive enamel and maximize patient comfort.

We're offering this package for $190.00 with an additional 10% off with our presale promo code. It contains a total of 32 strips, 8 of each (Yellow Starter 0.06mm, Red Opener 0.12mm, Dark Blue Widener 0.15, Green Extra-Widener 0.20mm).

  • Single-handed design offers optimal tactile control
  • Will not cut lips or gums and eliminates gagging
  • Flexible strip will contour the curvature of the tooth without creating subgingival ledges or sharp corners
  • Reduce binding and prevent residual crowding
  • Easy access to tight anterior or posterior areas
  • Autoclavable up to 280 degrees (steam heat only, not dry heat), and multi-usable

ContacEZ_IPR_1.png

IPR Optional Strips Package

The strips in this package allow for in-depth personalization to suit the variety of different cases and clinicians' preferences involved in interproximal reduction. These strips contour the curvature of the tooth to safely and efficiently reduce interproximal enamel without creating sharp corners.

These optional strips offer a larger starter strip (0.10mm Clear strip), a single-sided 0.12mm widener (Cyan strip) and two thicker options for widening (0.25mm Purple widener and 0.30mm Brown widener).

We're offering this package for $190.00 with an additional 10% off with our presale promo code. It contains a total of 32 strips, 8 of each (Clear Single-Sided Opener, Cyan Single-Sided Widener, Purple Super-Widener, Brown Mega-Widener).

ContacEZ_IPR_2-1.png

ContacEZ IPR Strips - Combined Package

This package combines the IPR Strip System and the IPR Optional Strips packages for $245.00 with an additional 10% off with our presale promo code. The combined IPR strip system contains 8 of each of the IPR Strip System strips (yellow, red, dark blue and green) and 2 of each of the Optional Strips (clear, cyan, purple and brown) a total of 40 strips per box.

ContacEZ_IPR_Combined.png

 

Don't want any of the packages? No problem! Each of the IPR Strips are also being sold in our online store individually in a refill package of 8 or box of 32. 

Snap-On Disc Guard

Using these guards during interproximal reduction with discs helps to protect your patient's tongue, lips, cheeks and gums from IPR discs. We're offering 1 package which contains 20 disc guards for $40.00 with an additional 10% off with our presale promo code.

  • Quickly snaps on and off
  • Provides safety and peace of mind
  • Economical and cost-effective
  • Transparent plastic
  • Clearly see the spinning disc
  • Single-patient use, disposable
  • Can be used with discs, rubber wheel, and brush wheel

Snap-on-disc-guard-1.png

We are offering these packages and each of the individual IPR strips along with the snap-on disc guard at these discounted prices for a limited time. Take advantage of these great pre-order prices as they will only be available until May 3rd.

  Click to pre-order!

Estimated shipment - May 3rd 

ClearCorrect Scores Another Victory With the Federal Circuit

Align Technology Fails Again to Overturn ClearCorrect Victory in Widely-Watched ITC Case

ROUND ROCK, TX--(Marketwired - March 31, 2016) - ClearCorrect, LLC, a leading U.S. manufacturer of clear aligners, is pleased to announce that the United States Court of Appeals for the Federal Circuit today denied the petitions for rehearing en banc that were filed by the International Trade Commission (ITC) and Align Technology, Inc. in case number 2014-1527. This is another U.S. court decision in favor of ClearCorrect, supporting the company's position that its clear aligner product complies with legal standards and does not infringe Align's patents.

The ITC or Align Technology may ask the United States Supreme Court to review the case, but such a review is unlikely to occur under the present circumstances. Last November, the U.S. Appeals Court ruled in favor of ClearCorrect, ruling that the ITC was without jurisdiction to regulate electronic transmission of data and today's reaffirmation of that decision is a victory not only for ClearCorrect, but the entire orthodontic industry.

"Denial of these petitions solidifies our victory in both actions we faced in the ITC," said Jarrett Pumphrey, ClearCorrect's CEO. "Based on the Federal Circuit's ruling last November, we expected today's outcome and are pleased that we will have no liability from either of these cases," he added.

"Today's result, coupled with last year's settlement of a civil action with Align where both parties agreed to dismiss their claims, means that three-quarters of the litigation Align initiated against ClearCorrect has now been resolved," said Michael D. Myers, ClearCorrect's attorney in the case and a partner with the Houston, Texas law firm McClanahan Myers Espey, LLP.

Align's final remaining lawsuit against ClearCorrect is a patent infringement case in a Texas federal court that had been stayed pending the resolution of the ITC actions. In anticipation of this case, ClearCorrect initiated reexaminations with the United States Patent and Trademark Office (USPTO) of 6 of the 9 Align patents asserted in the suit. The USPTO has the jurisdiction and authority to judge the validity of patents. Those key patents are now at risk of being cancelled, as thus far, the USPTO has indicated agreement with ClearCorrect's position that all 75 claims of the patents in question are invalid.

"Unless and until all the claims against the company are dropped or resolved, ClearCorrect must continue to defend itself. And those defensive efforts are progressing quite well," Myers said.

ClearCorrect case study: Dr. James Alexander

Orthodontic Practice US recently published a ClearCorrect case study: Dr. James Alexander discusses a way to avoid traditional PVS impression.

Utilizing CEREC scans with ClearCorrect for alignment

Tech Tip: Providers talk IPR

In a recent survey, we asked ClearCorrect providers to share their tips & tricks for performing IPR. As you'll see, we got a wide variety of responses, some of them contradictory. Everybody has their own preferred techniques.

Today, we're passing on some of the responses we got. Nothing here should be taken as official advice or recommendations from ClearCorrect or its employees—use your professional judgement to evaluate what's best for you and your patients.

Tools for performing IPR

Based on our responses, the most popular tools for performing IPR are diamond strips, followed by burs and diamond discs.

Doctors who prefer strips said:

  • “Floss first then diamond strip.”
  • “I usually underprepare the IPR so that the reduction gauge is difficult to fit between the teeth. If needed, more can be done later, often with a finishing strip, so that a closed contact can be reliably achieved.”
  • “I generally do IPR with manual strips every six weeks until contacts are not tight. I don't think this is better I am just more comfortable with this.”
  • “Pre-wedging prior to IPR and starting with strips prior to discs.”
    “IPR first with hand strips. Also, I find it easier to IPR when teeth are aligned first in the contact areas.”
  • “Start with the thin stainless steel strips and switch to the thicker carborandum strips as contacts become less tight.”
  • “I like to use a long finishing diamond to do IPR because I think it gives me more ability to maintain ideal proximal tooth contours.”

Doctors who prefer burs said:

  • “I find it’s easier to do IPR with burs as opposed to discs and strips. The smallest bur that I have found for 0.3mm is the mosquito interproximal from Neo Diamond. #1416f”
  • “I prefer a mosquito diamond to discs for IPR. I feel like I can shape it better.”
  • “I use ContacEZ high speed mosquito bur 1.6mm x 5mm length.”
  • “Mosquito burs are much easier to use and safer than discs, especially posteriorly.”
  • “I use a Brasseler mosquito bur from the cervical incisal to prevent lodging and make sure contact is completely broken.”
  • “I have stopped using the discs and use the mosquito bur to open the contact at the correct angle then I also use it to provide the correct proximal contours. Then I use the strips to finish to final IPR spacing and polish.”
  • “A high speed air turbine and bur seems to be the quickest and most controlled method.”

Doctors who prefer discs said:

  • “Start with low speed and stay in clear vision and control of the procedure. I use loupes 3x or microscope to do it.”
  • “It’s important to reduce straight (not angulated) and to carry the separation through the contact areas.”
  • “I use a slow speed straight hand piece with a VisionFlex disc. Fast and smooth and has many uses. You must be very careful.”
  • “Have different sized discs.”
  • “Just remember to use a guard on the wheel.”
  • “Use reciprocating files when extremely crowded and then rotary diamonds.”
  • “Use Brasseler perforated diamond disc - tissue guarded mandrel is an absolute must use.”

And some doctors prefer other tools:

  • “Always use diamond floss.”
  • “Use a combination of diamond discs on the slow speed hand piece with a soft tissue guard. Measure the amount of reduction done. Finish the IPR with hand strips. Check with an explorer to make sure that there is not a ledge left. Before starting any case involving IPR, inform the patient that it is needed.”
  • “I use a Komet, USA IPR kit with a reciprocating hand piece and safe tips. Then I finish with diamond strips to smooth and finish and contour. The gauges to confirm amount removed are integral as well.”
  • “I routinely perform IPR with a high speed hand piece and tapered carbide bur in conjunction with fixed appliance treatment. IPR occurs after separation of the contact points, and is performed on molars, bicuspids, and cupids as needed.”
  • “Use a high speed with a needle fine diamond. Check with the spacer key. Then round off the edges with the Diamond to restore anatomy. Done.”
  • “Get the electric wiggle saw. I do not know the name. Safe and effective.”
  • “On an extremely tight contact, I will place a separator for a few minutes prior to IPR. When I remove it and perform IPR, the patient is more comfortable and the strips do not break as often.”
  • “I use an oscillating hand piece made by Komet. It's easy to use and relatively comfortable for patients.

General thoughts on IPR

Some doctors prefer to perform IPR after aligning teeth, some from posterior to anterior and some prefer to perform IPR after arch expansion to allow access. Here are a few general tips from providers:

  • “Measure, re-measure, recheck before IPR, and also during the process.”
  • “Under IPR rather than over IPR.”
  • “The trick is to have the ClearCorrect technicians expand the arches to create more access to the area that is supposed to get IPR. I do use a mosquito nose diamond from SS White. It’s called a piranha diamond very fine, ISO FG# 392-016.”
  • “Do the posterior first, then anterior later.”
  • “Use a steady hand to be sure you don't open up too much space. I've used local anesthesia before on very sensitive patients.”
  • “Always use a gel topical anesthesia on the soft tissue, acts as a lubricant as well as anesthetic. And separate the teeth with a soft flexible wedge. It eases access and protects the soft tissue.”
  • “I like to use topical fluoride after IPR, trying to re-mineralize the cut enamel.”

Thanks to all of the providers who answered our survey. We hope you found something useful here.

Check out our Help Center for more helpful information on treating your patients with clear aligners and don't miss our upcoming advanced training webinar on IPR or our advanced training series of webinars on various topics related to clear aligner treatment.

Until next time…

Tech tip: FAQ about IPR

We sent out a survey recently asking doctors for their questions about IPR.

DrMah.jpegIn this week's tip, we've consulted with our Chief Technology Officer, Dr. James Mah, to get answers to your questions.

IPR and the treatment setup

ClearCorrect's role is to help you create the treatment setup you want for your patient. We can offer recommendations for the course of treatment for your patient, but those recommendations are never absolute. It’s up to you to make any necessary changes to customize an ideal treatment plan for each individual patient.

We can adjust all preferences related to IPR (which teeth, when and how, no IPR, expansion, limited IPR, limited expansion, etc.) or engagers based on your specifications. Just let us know what you want when you submit your case or when you review your treatment setup.

Questions about how much IPR to perform

Why do your IPR instructions always call for 0.3 mm?

If we don’t receive specific instructions from you on the amount of IPR you want done, we will go with our default increment of 0.3 mm IPR per interproximal each step. In some situations, we may recommend smaller increments of 0.1 or 0.2 mm of IPR.

These 3 increments of space can be created predictably if the right tools are used:

  • 0.1 mm of space is predictably created with hand stripping.
  • 0.2 mm can be predictably created with a single-sided diamond disc.
  • 0.3 mm can be predictably created with a double-sided diamond disc.

Doing any more than 0.3 mm of IPR at once to one interproximal is prone to problems. We usually recommend IPR in 0.3 mm increments to account for potential accumulated errors, such as:

  • When IPR is not performed correctly, the diamond disc can flex and create a “V” shape space which appears to be larger than it actually is. 
  • Hand stripping requires some force applied to the strip towards the tooth that needs reduction.  This force will sometimes move the teeth, which will make the space bigger. This space makes it look like the required tooth reduction occurred, when in fact it did not. Instead the teeth just shifted around to create space. When the aligners are put on the teeth, the space will be smaller than what is needed. 
  • A similar problem also happens when doctors force an IPR gauge into a space. They may think there is proper amount of reduction when all they really did was just move the teeth around.

Is it better to do IPR up to a point to correct rotations or to flare out to the labial?

This depends on the patient and the specific teeth. Clinician and patient preferences play a key role in determining the course of treatment. The treatment setup is your treatment plan and you are at liberty to make specific requests related to your individual patient.

How do I know when to do more or less IPR than scheduled?

Again, it depends on the specific situation. When considering IPR and the patient in front of you, you must understand that you are dealing with a biological system as opposed to a manufactured part. There are anatomic, biologic and patient variations at play which produce varying results. You will need to continue to follow what is happening with the patient and oversee treatment to obtain optimum results.

Also, knowledge of dental anatomy is important. Incisors have less enamel than other teeth and do not allow for as much IPR. Intra-oral radiographs can be used to check the amount of available enamel before submitting the case or performing IPR.

How do you measure the amount of IPR?

gauges.jpgThere are a few ways to check the amount of IPR:

  • IPR gauges (such as the ones sold by ClearCorrect) are commonly used.
  • Some dentists use the thickness of the IPR strip as a gauge, knowing that it is 0.1 mm thick. If you fold the strip over, it produces a thickness of 0.2 mm and one more fold results in 0.3 mm.
  • Some dentists use the width of the disc in the same manner.

I occasionally have difficulty with angulation of cuts, overlap, rotated teeth, access, insufficient space and possible over-reduction of one approximal surface vs. another. What should I do about this?

In some situations, it may be necessary to slightly procline the teeth and improve alignment before performing IPR, so that the appropriate tooth surface is reduced. For this reason, some clinicians prefer to perform IPR over several visits.

Scenarios like this are why many doctors do not schedule IPR at the first aligner appointment. Orthodontic tooth movement results in minor tooth mobility which allows for easier IPR.

If access is an issue on posterior teeth, you can request no IPR in posterior areas when submitting your case or reviewing the treatment setup.

What do I do to get exactly the same amount of reduction along the whole interproximal space?

When performing IPR you need to make sure that the strip or disc is completely through and past the contact point, and that the strip or disc is applied uniformly during the process. One common error is excessive tooth reduction above the contact point, leading to a “V” shaped interproximal gap.

The goal of IPR is to reduce tooth size while maintaining the original morphology of the teeth. In other words, smaller contact points between incisors should remain as such and not be flattened into broad ones. If in doubt, it is easier to carefully go slower with a strip than it is with a rotary disc.

Tight contacts make it difficult to perform IPR and for this reason, some clinicians prefer to start moving the teeth and take advantage of the associated tooth mobility before performing IPR. Another option is to start the IPR with a strip to overcome the tight initial contact and subsequently use the burr or disc.

Do you keep track with the total amount of IPR being performed throughout a case? My only concern is that at times it seems IPR is being done on the same teeth, and I worry about the patient having sensitivity due to loss of enamel.

Screen_Shot_2016-03-11_at_11.55.21_AM.pngClearCorrect represents the amounts and locations of recommended IPR on the treatment plan and treatment setup.

Our technicians usually won't recommend more than 0.3 mm IPR mesial of the canines, or more than 0.6 mm IPR distal of the canines and mesial of the first molars, unless specifically requested by the doctor. We have found that those values are conservative enough to maintain the enamel structure and to satisfy most doctors that have concerns about reducing too much enamel.

These default values are smaller for anterior teeth, because they have less enamel than posterior teeth. These values also take into consideration how the tooth will look at the end of treatment. 0.3 mm of IPR in the anterior is only 0.15 mm on one tooth, if a double-sided diamond disc is used. 0.6 mm of IPR in the posterior is only 0.3 mm on one tooth, if a double-sided diamond disc is used. Since posterior teeth can have more enamel removed, you can go back and round out the square corners by contouring after using the diamond disc.

Besides our recommendations, you should also keep track of the IPR that is actually performed on each patient. We have an IPR Tracking Chart that can help you monitor this. Each time you perform IPR it should be recorded and correlated with specific patient tooth morphology (check intraoral radiographs for thickness of enamel). 

Questions about IPR and spacing

The majority of the time you ask for a 0.3mm reduction but every time I create the 0.3mm, I end up with spaces and have to ask for more trays to close that space. Why is this?

There are several possible reasons that you may have ended up with spacing after doing IPR:

  1. Patient non-compliance.
  2. Teeth can shift unpredictably in treatment. Always be aware of this and only do IPR when it appears necessary, using the treatment plan amounts as a guideline. Your technical expertise and judgment takes precedence over any IPR recommendations.
  3. Technicians are working with digital images vs. the actual patients, so the instructions are an imperfect estimate of the amount of IPR that will actually be needed.
  4. Space closure in deep/heavy bite patients is difficult.
  5. Problems in impressions can result in inaccurate digital images.
  6. More than the required amount of IPR may have been erroneously performed.

Before performing IPR at any stage of treatment, you should check the patient’s mouth to see if treatment has been progressing as planned.

Interproximal contacts should be checked with dental floss at every visit and if the contact is not closing, you can request a digital power chain to close residual spaces.

What if I'm sure I opened the space to the prescribed amount, and when I get a notation to check for closed contacts, it's still open? If patient compliance is not the issue, should we go on to the next step, or try the current aligner for a longer period?

If patient cooperation and aligner fit are not issues, continue with treatment. The periodontal tissues are still remodeling and the residual gap may close later in treatment. Check the contact often and if it remains after alignment is achieved, request a digital power chain to close up residual spaces. 

I am concerned about creating a narrower interproximal space with less space for gingival tissue on some teeth. I still don't find any of the methods to do IPR perfect. They all present risks of iatrogenia and don't allow us to preserve the ideal tooth anatomy.

Generally interproximal tissues will remodel to accommodate the new tooth positions and there will not be any gingival excess. However, in some situations, such as the maxillary midline, this may be an issue requiring gingivectomy. 

However, these issues are all according to your preference. You can specify less IPR or no IPR when you submit the case or evaluate the treatment setup.

The hand system wears out pretty quickly and doesn't always create enough space. Some teeth can be stubborn to move and need more space, especially when the teeth are really crowded. What do I do when this happens?

This could be the result of clinical technique. Reviewing the different IPR techniques might be helpful. It could also be affected by the choice of which strip to use (course/medium/fine). These variables should be considered when performing IPR.

Questions about contouring and IPR

How do I create a natural contour instead of just a flat side?

When contouring, knowing the various IPR techniques available to you and using the one most applicable for the case at hand is important to achieve the desired result. Using hand strips after use of a diamond disc can help with rounding out some corners.

It also may be necessary to slightly procline the teeth and improve alignment before performing IPR so that the appropriate tooth surface is reduced, and then perform IPR over several visits.

General concerns about performing IPR

I get worried about the accuracy of the proposed design.

This is why it is important to see patients on a regular basis to oversee their treatment progression. Additionally, this is a concern of many doctors when first performing IPR. With more cases, treatment, and experience, this concern fades.

I find using diamond saws very scary. It’s easy to create a bloody mess in a blink of an eye. The patients really dislike the sound of the diamond blade hacking away at their dentition. It takes a lot of effort to even start the pass thru. The feel of grit and the taste of blood make them want to run.

Knowing the various IPR techniques available to you and using the one most applicable for the case at hand is important in scenarios where you have a nervous or scared patient. There are multiple available techniques for IPR (manual strips, discs) that doctors can choose from. Dentists have varying levels of comfort with each system. The choice to perform IPR or not is entirely up to you. You can always make custom requests regarding IPR when you submit your case or review the treatment setup.

How do I reassure my patient I'm not hurting or damaging the teeth when I do IPR?

Discuss enamel thickness and dental anatomy with the patient. You can let the patient know that occlusal enamel reduction through everyday chewing is a normal occurance that happens as the patient gets older. If this is a significant issue for the patient, one alternative is arch expansion to reduce or eliminate IPR. However, there are also compromises and risks involved in arch expansion.

I would like to know more about when it is appropriate to do a little unscheduled IPR to help prevent teeth from getting off track.

During every visit you can check for excessively tight contacts with dental floss. If you find that tight contacts are an issue, you can perform a little hand stripping to help keep treatment from going off track.

Should the IPR gauge fit tightly or passively?

It should be fairly passive as a tight fit will result in compression of the PDL and natural tooth mobility may be confused with available space.

We hope you found this information helpful! There's lots more where this came from—check out our Help Center, which is filled with useful information for treating your patients with clear aligners.

Also, don't miss our upcoming advanced training webinar on IPR or our advanced training series of webinars on various topics related to clear aligner treatment.

Until next time…

Bite registrations are now optional

No bite registrationThat's right, you can now submit a case with just upper & lower impressions—no bite registration necessary. (Of course, we love intraoral scans, too.)

Why the change? We've developed new software that automatically articulates the arches in maximum intercuspation.

For the vast majority of cases, this is as accurate as (or more accurate than) aligning models based on a bite registration. Our technicians also double-check the occlusion against the photos you provide. Going forward, maximum intercuspation will be our default alignment technique for all cases, even if we receive a bite registration.

There may still be a few scenarios where the bite registration is preferable (for instance, when the patient has a posterior open bite).

If you want us to base the occlusion on a bite registration instead of maximum intercuspation, please let us know in the instructions when you submit the case.

As always, you're in charge.

If you have a case that's been held up waiting for a bite registration, we'll take it off hold and you should receive a treatment setup soon.

Until next time…

Tech Tip: Using IPR to avoid case revisions

This tech tip is an oldie, but a goodie.

Sending in a case revision before doing some troubleshooting can waste money and chair time. We see a lot of case revisions submitted when unpredictable tooth movements (such as extrusions and rotations) just aren't happening. Teeth need space to complete any type of movement, and when they don't have enough, it can cause tracking or fitting issues. These tight contacts are common and can appear at any time in treatment, due to the nature of teeth and the patient's physiology.

Even if you follow the treatment plan to a T, and the patient is completely compliant, you may still need to perform IPR.

You can avoid submitting an unnecessary case revision by using these IPR techniques:

  • Always check for tight contacts before submitting a case revision. You can easily alleviate tight contacts by hand stripping, as demonstrated in our IPR tutorial video.
  • Take IPR into your own hands! The recommended amounts of IPR in the treatment setup and treatment plan are for guidance only. You are the doctor, and are the one ultimately treating the patient. Small amounts of unscheduled IPR can get treatment back on track much quicker than submitting a lengthy case revision.
  • Use your good sense -- don't perform IPR in a spot where there's already space, even if it's recommended on the treatment plan. Too late? Don't worry, it's an easy fix. At the end of treatment, the spaces caused by doing too much IPR can be closed with a digital power chain in a refinement.
  • If you still have questions, we have articles in our Help Center dedicated to performing IPR and troubleshooting other related issues. Or, you can alway contact a knowledgeable support rep; they will help you review your patient's treatment so you can decide what to do next.

We hope you found this information useful!

Also, don't miss our upcoming advanced training webinar on IPR or our advanced training series of webinars on various topics related to clear aligner treatment.

Until next time...

Carestream Dental announces NEW 3600 Intraoral Scanner

Dentistry Today recently sat down with Dr. Ed Shellard to talk all about the new CS 3600 intraoral scanner from Carestream Dental.