Tech Tip: All about scanners

Making accurate dental impressions is easily the most essential part of submitting a case. There are many different options out there for capturing dental impressions, from traditional impressions to the wide variety of intraoral scanners available on the market today.

3-D technology has had a significant impact on dentistry in the last 20 years, and it is only expected to increase in the coming years. More and more doctors are moving over to intraoral scanners.

We thought that a tip covering intraoral scanning with ClearCorrect might be helpful, whether you already use an intraoral scanner or if you're considering one.

Intraoral scanners

A study from 2014 found that the use of intraoral scanners could significantly accelerate the work flow of making impressions.

Some benefits of using an intraoral scanner include:

  • More comfortable for patients than conventional impressions
  • Save costs on impression materials
  • No shipping hassles
  • Higher accuracy than traditional impressions
  • Fewer errors resulting in having to re-impress
  • Facilitates sending scans to ClearCorrect electronically, resulting in a faster turnaround

ClearCorrect accepts records from most intraoral scanners currently on the market.

Scanners_1.png

With the wide variety of intraoral scanners available, selecting the best intraoral scanner for you really comes down to your preferences. Some things you might want to consider when choosing a scanner:

  • Is the scanner portable?
  • Is the scanner light and easy to use?
  • Will the scanning experience be comfortable for patients?
  • Is there a cost for image export and storage?
  • Is the software for the scanner compatible with your practice management software?

Submitting a case to ClearCorrect with scanners

You can upload scan files from any intraoral scanner to ClearComm as long as the file is in STL format. (STL is an open, industry-standard file format that can be exported by most popular scanners.) Export your STL files from your scanner to your computer, and then upload those files just like your photos when you submit a case online, or on the case page after submitting.

Submit_a_case_8.png

STL files are not necessary if your scanner has the option to select ClearCorrect as your dental lab and upload scans directly from the scanner. CEREC Connect and TRIOS currenty offer this option.

We provide instructions for some of the common scanners:

Model or impression scanners

We also accept scans from model or impression scanners like Motion View's Ortho Insight 3D Scanner. Whether you're using an intraoral scanner or a model or impression scanner, ClearCorrect works with your team to accept digital files enhancing productivity and quality.

Scanning tips

Here are a few tips for using scanners:

  • We strongly recommend that you visually inspect your STL files before you submit them to us. We recommend netfabb Studio Basic, which is available free for Windows, Mac, and Linux. Other STL viewing options include viewstl.com, MiniMagics and FreeCAD.
  • Some scanners output several files, but the only files we want are the upper and lower arches. The arches should be saved in separate files, with the arches oriented in occlusion.
  • Scan both arches, even if you're only treating or revising one of them. Recreating the occlusion based on one arch is prone to error. (This advice applies to PVS impressions as well.)
  • We prefer "closed shell" models, but "open shell" models are acceptable too.
  • To prevent aligners from flaring at the edges, always capture at least 3-5 millimeters of gum in the scan.
  • While bite registrations are no longer a requirement for submitting PVS impresions to ClearCorrect, this is still part of the workflow with some scanners. You can capture more accurate bite scans by including as much of the occlusion as your scanner allows.
  • We can't provide support for your scanner software, but if you have any other questions, as always, our knowledgeable support reps are here to help.

We hope you found this information useful!

Until next time…

Tech Tip: Case submission FAQs & tips from providers

In a recent survey, we asked some of our providers about any questions they might have on the topic of case submission, prescription and treatment setups. Below are some of the questions and answers. We hope you find this information helpful!

FAQ about case submission, prescription & treatment setups

Is ClearCorrect now 2 weeks for each aligner? I’m still using the 3 week method.

We did change our default wear schedule from 3 weeks to 2 weeks in 2015. At the same time, we also added the ability for you to choose your patient's wear schedule when you submit your case. With this change, you're able to request a 3-week, 2-week, or even 1-week wear schedule and you can dispense as many aligners as you see fit at each appointment. (This only applies to new cases--any cases that started on a 3-week schedule should still be on that schedule.) We recommend that most patients wear each set of aligners for at least two weeks. See our full article on aligner wear schedules.

Wear schedules can be viewed in the treatment setup and in the fine print on the treatment plan.

If a bite is no longer needed, how do we bypass this in CEREC Connect?

At this time, a bite scan is a requirement and part of the workflow when scanning with CEREC Connect. While we've made bite registrations optional, most doctors still like to take a bite scan to have as a record to compare to the bite that we provide in our treatment setup.

I understand that this system is only for anterior teeth. Is that correct?

No, ClearCorrect is an advanced system of clear aligner therapy that uses the latest digital technologies, design and clinical approaches to treat various types of malocclusion, ranging from simple to advanced extraction and surgical cases depending on the knowledge and expertise of the doctor.

What are the most common issues that cause a Limited 12 aligner case to be elevated to an Unlimited case?

When the ClearCorrect technician reads the case submission form, they try to follow all of the doctor's instructions taking into account the requested case type. However, if they can't follow both the treatment plan and case type instructions, they will prioritize the treatment plan instructions over the case type which can lead to upgrading the case to an Unlimited. If it's noted on the case submission form that the case type is a higher priority over the treatment plan, along with a note of which correction is allowed to be compromised for the case type, then our technician will follow those instructions instead of their normal protocol.

I’m not sure about the amount of trays to plan for. Maybe a guideline to selecting the right case type?

In 2015 we made a change where by default and at no charge to you, our technicians recommend a case type appropriate for the treatment you prescribe, which eliminates the need for you to choose the case type for your patient. However, if you have a preference, you can indicate it when you submit the case.

Submite_a_case_2.png

Either way, the case type won’t be final until you approve a treatment setup and pay for the case.

If you want to choose your case type, we've prepared a simple chart to help you predict which treatment option might be best for your case:

option_comparison_chart.png

Can I ask for specific sizes or shapes of attachments for the setup?

Not at this time. Engagers are an active area of research and development at ClearCorrect and elsewhere. Many variations of engager shapes have been proposed and discussed in literature and professional forums, but in practice, once 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 the simple horizontal and vertical engagers that we've been using for the last ten years, which have proven sufficient to help with movements requiring an engager.

Fortunately, because of the way we trim our trays, our aligners are 2-4 times stronger than our competitors. This can reduce the need for engagers in many cases.

It looks like some overcorrection was built into the treatment setup. Is this correct?

Overcorrection is only added to the case per the doctor's instructions. Overcorrection can be requested at the beginning of a case when filling out the submission form, when submitting a revision or when reviewing/approving the treatment setup.

No bite turbo or bite ramps were offered, is this something that will be coming or is it even necessary with the greater gingival coverage that ClearCorrect has in their aligners?

Doctors can request lingual engagers to prevent full closure of the teeth. This is an advanced treatment technique, and should be monitored carefully. Whether a bite turbo and/or bite ramp is necessary would be determined on a case by case basis.

In cases with anterior interproximal reduction, how can I have a virtual power chain added to the end of the treatment sequence so that I have all the required aligners, including for the power chain, without having to request a revision?

When submitting the case, just ask for overcorrection with a digital power chain on the last two steps in order to get a virtual power chain without having to request a revision.

How do you determine which teeth will start the movement? (Or, phrased differently); How do you stage treatment?

We use protocols that have been developed by our Chief Technology Officer, orthodontist Dr. James Mah; ClearCorrect founder Dr. Willis J. Pumphrey; and our VP Products, Paul Dinh, CDT. These protocols are applied on a case-by-case basis by our technicians to help get the outcomes you prescribe for your patients.

Is there a process that I can tweak the final treatment setup myself?

Not at this time, though we are aware that doctors are interested in this functionality. The current process for adjusting your treatment setup is described below.

How do I make adjustments to a treatment setup?

If the model looks inaccurate, you want to move the teeth differently, or you want to cancel the case, click DISAPPROVE when viewing the treatment setup and let us know what you want to do. Our technicians will do their best to make any changes you request and upload a new version of the treatment setup for your approval within a few days.

Treatment_Setup-2.png

Treatment_Setup_8.png

I have difficulty with viewing the setup. It isn’t real clear to see the final result. I kind of just go on faith that it is going to look good.

At the bottom left of the setup, you'll see a timeline representing every step of the case. The starting position of the teeth is shown at the left. Steps with checkup appointments are numbered on the timeline, and the final position of the teeth is represented on the right as a retainer.

Treatment_Setup_2-1.png

To navigate between steps, you can drag the slider, click on a step, click the Previous and Next arrows, or click Play to animate the treatment from beginning to end. You can click Previous at the beginning or Next at the end of treatment to quickly toggle between views before and after treatment.

Shortcuts are available for the most common views: Upper occlusal, Lower occlusal, Right, Front, and Left. You can also rotate the model to view the teeth from any angle by clicking and dragging.

Treatment_Setup_3.png

I sometimes need help in deciding on the treatment setup.

When approving a treatment setup, it's best to begin with the end in mind - consider the whole treatment and what are the goals for that particular patient. Also, when filling out the case submission form, the more information you give the better treatment setups you'll receive.

For more information, see our recommendations for how to evaluate the treatment setup in our Help Center article on this topic.

As a “bracket man” for years, I feel that the torque movements are hard to envision. Can some support evidence or outcomes be made available to give me more confidence?

We understand that being able to see some successful outcomes is helpful. We offer a number of different case studies covering a variety of scenarios from treatment of a Class II with crowding and a deep bite, to treating an anterior open bite with clear aligners. You can check out all of our case studies in our Help Center.

Provider tips & tricks

Some of our providers offered a few tips & tricks for submitting cases. Nothing here should be taken as official advice or recommendation from ClearCorrect or its employees. It’s up to you to use your professional judgement on what is best for you and your patients.

  • "I usually let ClearCorrect dictate the course of action. I have had an extraction case that I had never done before and the ClearCorrect technician walked me through it and said that she had seen my other work and was sure that I could do this as well. It made me feel good."
  • "I look at my comprehensive diagnosis and go through in my head step-by-step what I need to correct the deficiencies."
  • "I like to avoid placing attachments at the initial stages, so that the patient can become accustomed to the appliances before making it tougher to remove them."
  • "I would recommend that all doctors finish with a digital power chain."
  • "I would overcorrect all rotations and ask for power chain to close any original spacing. My experience tells me that less engagers allow better fitting and tracking of aligners."
  • "I always leave 1mm of overjet between anteriors at completion to prevent a slight posterior open bite."

Thanks to all the providers who answered our survey!

Check out our Help Center for more helpful information on treating your patients with clear aligners.

Until next time...

Tech Tip: An in-depth look at impressions

Perhaps the most important aspect of submitting a case with ClearCorrect is making sure that you have clear, accurate intraoral scans or impressions. We thought we'd cover some of the basics on the topic of taking impressions, along with some new information that you may not know.

We love intraoral scans, but if you prefer taking PVS impressions, we happily accept them. We require both upper and lower impressions, even if you're only treating one arch. As we've mentioned recently, bite registrations are now optional.

You can use nearly any type of tray you like for your impressions except for metal trays. We don't return your impressions, so it's best to use disposable trays.

PVS or VPS materials work best for impressions. Polyether (Impregum) will work as long as the detail for the gum lines are there. In our experience, Sultan Genie™ VPS and Premium Dental VPS impression materials are easy to work with and deliver consistent results. If you prefer a different polyvinyl or polyether impression material, feel free to continue using what you're comfortable with. Alginate is not acceptable because it dries out and distorts.

A good impression looks like this:

Good_Impression.png

We recommend one-step impression methods for the best results, but we'll accept two-step impressions as well.

Make sure your trays are properly sized to fit all the teeth and surrounding gums. Because our aligners cover beyond the gingiva for improved retention, the importance for obtaining full and complete impressions cannot be overstated. Impressions that may have worked for other clear aligner companies, should not be assumed to work for our product (especially where the gingiva is not covered in the impression).

Our most common issue with impression distortions is material that hasn't fully set before being removed. There are a few simple things you can do to prevent this problem:

  • Set a timer and make sure to follow the directions for your material exactly
  • Discard the first inch of material that comes out of every new mixing tip
  • We recommend waiting an additional 60-90 seconds longer than instructed before removing the trays from the patient's mouth

Did you know that performing a cleaning before taking impressions, removes plaque which can make for better impressions and could reduce the amount of residual spacing at the end of treatment?

Any existing spaces or gaps that are filled with plaque can be properly caught in an impression if a cleaning is done before impressing. With the plaque removed, the spaces or gaps get accurately detailed in the impression and when the aligners are made, they can indent into those gaps and push out any plaque that develops during treatment. This process could reduce the amount of residual spacing at the end of treatment.

Help Center articles

Our help center has several helpful articles on the topic of impressions. Maybe they can be of use to you. Check out some of these great articles here:

We hope you found this information helpful! Don't miss our upcoming advanced training webinars on case submission, prescription & treatment setups or our advanced training series of webinars on various topics related to clear aligner treatment.

Until next time…

Tech Tip: Providers talk engagers

In a recent survey, we asked some of our providers to share their tips & tricks for placing and removing engagers.

Nothing here should be taken as official advice or recommendation from ClearCorrect or its employees. It’s up to you to use your professional judgement on what is best for you and your patients.

As the clinician it is important for you to be aware of different approaches, so that you can customize treatment for each patient. By way of example, while it may be possible to place engagers all at once in one patient, it may be necessary to cut the engager template and place engagers separately for another patient. Another example is the availability of various composite resins. Some patients seem to have no problems with engagers made from flowable resins, and with others they can wear away and break down. In this situation, a filled resin or other more durable resin can be used. 

We wanted to pass on some of these responses in hope that you might find them useful in treating your patients.

Tips and tricks on engager materials/composite/flash

Doctors who preferred flowable composite said:

  • “I use only flowable composite to fill the engager templates. It is easier and fills the template without voids. I know you recommend a two fill system, but it doesn’t seem there is time to do that and still get a good fill. I have had good luck so far with my variation of your system.”
  • “When placing engagers, use a little drop of flowable to “wet” the inside of the well prior to injecting paste, then a dab of flowable to “wet” the interface of paste and tooth when going to mouth.”
  • “Flowable composite seems to work best versus packable products. Also, checking the bite after placing engagers can prevent some engagers from interfering with the bite and being dislodged. “
  • “A “thick” flowable resin like GC Universal Flo will work well, without need for two materials, thin flo and thick paste.”
  • “I use flowable composite first, then a filled resin when filling the template.”
  • “The combo of flowable composite placed on the etched, primed/bonding agent light cured teeth and heavier composite place in the lubed engager reservoir works predictably on seating and curing. The sandwich of light and heavy composite will leave some flash to remove.”

Doctors who preferred different composites & bonds said:

  • “Using a lower viscosity composite, but not flowable.”
  • “Blue phosphoric acid etch bonds better.”
  • “I use a packable composite and place the college plier’s tips in either embrasure, forcing the aligner into closer contact with the tooth.”
  • “Use cheek retractors, spot etch, bond and use Surefil flow, which has been my best result in placing engagers.”

On the topic of flash, doctors said:

  • “I find that if I leave a little flash they stay on better.”
  • “They key is high speed finishing off any flash or over extension of composite. Wearing an LED headlight with loops and air drying the tooth/engager composite junction shows excess flash the best. Always verify that the next corresponding aligners seat completely in the excess flash removal evaluation. I use yellow or red striped carbide finishing points (like a 7901 or 7102) to remove the flash. Remove some with a high speed and water spray, air dry, repeat until satisfied and remember less is more.”

Tips and tricks for attaching engagers

Doctors offered us a multitude of tips on technique, tools and even timing for placing engagers. Here’s what they had to say:

Doctor’s tips on engager placement techniques:

  • “Poke a small hole through the engager tray from the inside of the engager area to extrude excess air and composite material, then perform minor adjustment on the surface of the engager to smooth if necessary.”
  • “Make a pin-hole in incisal edge/cusp tip of template of each tooth getting an engager. Hydraulic pressure relief as seat filled template allows easier, more complete seating.”
  • “Using a very small bur the diameter of an adhesive tip (I use Flow Tain with disposable tip), drill a small hole in middle of engager on the template. Prep the tooth as recommended, place template on the teeth and then fill the engager bubble with adhesive through the hole. This ensures the correct amount every time.”
  • “For placing engagers, pre-load composite in wells, cover from light bonding procedures, then directly to mouth, less change for salivary contamination by pre-loading.”

Doctors tips for engager template removal:

  • “The composite tends to stick to the template tray unless you wipe with alcohol and then apply the Vaseline.”
  • “I cut up the engager template and only attach 2 at a time.”
  • I usually cut the template. I keep 3 teeth, the engager tooth and the 2 adjacent teeth on each side. That way it will be easier to remove the template once the engager is placed.”
  • “Trays definitely need modification prior to placing engagers. I separate the right & left sides, and remove the lingual portion of the tray just past the incisal edge. This way I can peel the tray off easily. I also place a light coat of Vaseline with a micro brush on the inside surface of the tray where the composite will go.”
  • “On the template for the engagers, I remove the aligner material on the gingival side just below each engager well, right up to the edge of it, either with a high speed hand piece or a hole punch. Removing the gingival area below the engager wells allows me to wipe away any excess composite material that extrudes out of the gingival side of the engager well. It also provides me a purchase point to be able to lift up the template off of each tooth that has an engager.”

Doctors tips on tools to use for engager placement:

  • “I do better with composite out of a fine needle syringe. It seems to be strong enough to hold up, but there is some excess flash that needs removing.”
  • “Attaching with Filtek Ultra resin worked so much better than anything else for me. Microetching first is a must.”
  • “Pumice and selective acid etching before regular bonding routine.”

Doctor’s tips on timing of engager placement:

  • “Attaching to rotated lower canines always presents a challenge because of the super-acute angles between the canine and the adjacent incisor. You should request to hold placement of those engagers until the last possible time during treatment.”
  • “Sometimes to ensure proper placement, I will have the patient wear the trays for one week and then come back and place the engagers.”

Tips and tricks for removing engagers

Based on our responses, doctors seem to favor burs and using a combination of burs, discs and polishers.

Doctors who preferred burs said:

  • “I find that the best FINAL tool is a small pointed low-fluted carbide bur.
  • “Use Braessler ET long multifluted burs to remove engagers and/or excess.”
  • “Use a diamond or carbine finishing bur, get close to the enamel, then use enhance polisher to remove residual resin. Does not harm the enamel.”
  • “I only use a finishing bur. It helps to dry the surface to see if any bond remains. If there’s bond/resin left, the surface will be dull.”
  • “Use a high speed composite finishing bur, dry, followed with a composite polisher.”
  • “I use older ET composite shaping burs as they are less likely to cut enamel.”
  • “12 fluted bur.”

Some doctors prefer a combination of tools:

  • “I use a band remover to remove engagers and then go to a fine diamond bur then carbide flame bur and polish the surface with something like a pogo.”
  • “I use a sandpaper disc and football Brasseler finishing bur to remove them.”
  • “I remove engagers with 1) medium diamond to very thin resin, then 2) carbide finishing bur to enamel resin layer, then 3) finishing/polishing discs, points and brush and last, 4) burnish fluoride.”
  • “To remove engagers, I use a diamond finishing bur to remove the bulk and then switch to a Softlex disc for the final removal.”
  • “I first use a scaler, then Soflex discs, dry to better visualize the borders of composite. I check with the side of an explorer to see if the composite abrades some metal or if is completely removed.”

And some doctors prefer other tools:

  • “Remove with a white stone and high speed hand piece.”
  • “Use a high speed dry (no water so you can see the difference between the composite and the tooth structure, then use composite polishers to finish.”
  • “I use a fine diamond for gross reduction and finish with Dentsply enhance.”
  • “Use G-Bond provided by ClearCorrect, red stripe (fine) bur to remove 90%, then usually I’m able to flake off with a scaler. Not fun but it works without damaging the enamel.”
  • “Dura white stone high speed ulta dent polishing brush.”
  • “I like to remove the final layer of composite with a Brownie point, at a reduced speed.”

Doctor’s tips on engager removal techniques:

  • “I like to polish after removing engagers to make sure all is smooth.”
  • “You can always shave down engager slightly if too difficult to remove aligner initially.”
  • “Have patience in removing. Using a porcelain polishing diamond wheel works very well. When the resin is very thin a scalpel can be used or a rubber resin polisher will help remove resin without removing enamel.”
  • “Use a fluoride treatment after removal.”

Tips and tricks for lubricating

Doctors offered us several different tips for lubricating the engager template before installing, helping with template removal.

  • “Lubricate the template with Vaseline.”
  • “Apply mineral oil to the aligner beforehand so engagers don’t come off in the tray.”
  • “Make sure template is thoroughly coated with a separator and pull template away facially not incisal after curing.”
  • “Your seating video is spot on. The key is to lube the engager housing with either a dab of Vaseline or separating liquid (Sure Sep by Belle de St. Claire lab products).”
  • “We coat the template with Pam cooking spray before bonding the engagers. It makes it easier to remove the template. With multiple engagers the bonding material would sometimes fracture during template removal before using the releasing agent.”
  • “I find that the template needs to be wiped with alcohol before using Vaseline. My guess is that there is some type of oxygen inhibiting layer that the composite sticks to.”
  • “I spray the inside of the aligner with a light mist of non-stick cooking spray and then air blow it out of the engager well, not allowing any to pool up but still leaving a thin amount of separating medium. The separating medium in the template helps prevent the composite from bonding to the template and also aids in disengaging the template from the teeth which minimizes the engagers popping off.”

General tips and tricks regarding engagers

From installation techniques and engager modification to patient preparation, here are some general tips offered from providers.

  • “The engagers are pretty sharp to the lip so I always polish them a bit.”
  • “ Have the patient wear the engager stent/tray for at least a week before placing the engager.”
  • “I do one quadrant at a time. Usually there’s an area on the tray that serves as the best point for removal. You may want to consider adding something similar to a removal button on PFMs.
  • “Important to place pressure on the template from buccal and lingual. This ensures the engager is not too thick.”
  • “Magnification is a must.”
  • “Keep area clean and dry. Etch the enamel very thoroughly. Fill template and push the material into each attachment to adapt it well.”
  • “I make sure to abrade the enamel slightly with air abrasion or diamond and then etch. I fill with composite slightly below level, then place a dot of flowable composite to fill the last bit so it is level before placing in the mouth.”
  • “I always round them just a little after I place them. They seem to work fine and it makes the trays easier to insert and remove. I know that could cause some trouble at some point, but so far it has not.”
  • “I do them one at a time so I can press the engager matrix hard against the tooth with the back of the tips of a cotton forceps.”
  • “You should overbuild the engager and reapply material if it does not look accurate.”
  • “Sometimes we like to modify the tray and enlarge the engager to act as a hook and use the engager with elastics/rubber bands to help super erupt a tooth.”
  • “We prefer longer treatment without engagers than shorter treatment with engagers. We also prefer to have engagers removed at the earliest possible step instead of waiting until treatment completion.”
  • “I try to always prepare people for engagers: “You’ll have a big, tooth-colored blob on these three teeth…etc. This way they don’t freak out: “You told me I could take them out but I can’t take this blob out!”

Thanks to all of the providers who answered our survey!

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 Case submission, prescription & treatment setups or our advanced training series of webinars on various topics related to clear aligner treatment.

Until next time…

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…

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…

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...

Tech Tip: Tight Contacts

What are tight contacts?

Tight contacts exist when there is tension between two teeth and it is undetected by impressions and 3D models. 

Here's an example of tight contacts:

0.3mm of IPR is requested between teeth 8 & 9, but there is tension (hidden pressure) between 9 &10.  When space was created with 0.3mm of IPR, the pressure was released between 9 & 10 now creating normal contact levels since tooth number 9 has been given space to move over. This means depending on how much tension was between 9 & 10, the IPR space is now smaller, 0.2 or 0.1mm, but still not the amount required by the treatment plan.

Causes

Tight contacts between teeth exist naturally due to the patient's dentition (crowding in the arch) which will then cause the teeth to become active (spring loaded) once space is created during orthodontic treatment.

One of the consequences of tight contacts is that the planned treatment may go off track. Or in the case of the last aligner, you may still need some slight movement to get them into their final position.

Solutions

How to check if you have tight contacts

When flossing between teeth if the floss has a hard time popping in and out then you know that you have a tight contact. (If the floss pops in and out easily then this is light to moderate contact.) 

What to do with tight contacts

When you have tight contacts, you do not necessarily need to request a case revision, which could be lengthy and delay treatment. Try the following actions:

  • Floss between the suspect teeth (areas of misalignment) to check for tight contacts as described above.
  • If tight contact exists, you can do some  hand stripping to create approximately 0.1mm of IPR. 
  • If there are no tight contacts (but there is some misalignment), you can still do a little IPR (0.1mm) to help create some needed space.
  • If you have tried the above, and feel you've created sufficient space, but still have misalignment, at this point you may need to submit a revision.

Note: IPR is done at your discretion. We advise doing hand stripping which creates 0.1mm of space. If you do 0.1mm of IPR at a time, any excess space created by additional hand stripping (not on treatment plan), will be fairly easy to close at the end of treatment with a revision by requesting a digital power chain.

Tech tip: Undesirable undercuts

Desirable vs. undesirable undercuts

Mosby's Dental Dictionary defines an undercut as "the portion of a tooth that lies between its height of contour and the gingiva, only if that portion is of less circumference than the height of contour." Aligners rely on these naturally-occuring desirable undercuts for normal retention.

Undesirable undercuts, however, are too retentive, making it difficult to remove impressions or aligners. Some common causes of undesirable undercuts include:

  • Gingival recession creating a notch at the cementoenamel junction
  • Under-restored dental implants and bridges
  • Anomalous tooth morphology
  • Overcontoured restorations

How to deal with undesirable undercuts

One of the most common techniques for dealing with undesirable undercuts is to block them out:

  • Before taking impressions, fill in the undesirable undercuts with a soft material that will not bond to the impression (like wax). This will make the impression easier to remove, and also eliminate those undercuts from the resulting 3D model, making the aligners easier to remove as well.

Another technique is to trim the medium body material:

  • Between the first and second steps of a two-step impression, use a knife to trim away the impression 2 millimeters above the gingival in the medium body material. This will ensure that the only material covering the undercuts is the flexible light body material, allowing the impression to be removed easily.

Note that if you use this technique (or if you take intraoral scans), the undesirable undercuts are still likely to show up in the 3D model and aligners. In these situations, you may want to ask ClearCorrect to block them out digitally:

  • When you submit the case, use the additional instructions section to describe any undercuts that you want ClearCorrect's technicians to digitally fill in. When you get the treatment setup, inspect these areas of the 3D model carefully to ensure that they meet your expectations.

We hope this information was helpful to you!

Until next time...