Tech Tip: IPR - Contouring

When you perform IPR with a diamond disc, you may end up with flat surfaces between the teeth and sharp corners at the edges. This isn't necessarily a functional problem, but some doctors and patients find it aesthetically displeasing. If the square corners are touching on the lingual, sometimes the buccal contact looks open. Proper contouring can conceal the evidence of IPR and restore teeth to their natural contours.

Contouring after IPR 1.png

Aligning teeth with rounded contacts can also reduce the arch length and reduce the appearance of open space between teeth. A rounded surface allows for the tooth to rotate without having the corners coming into contact.

Hygiene can also be an issue, because natural rounded contacts have a spot surface contact and a flat IPR surface has a broad larger contact. This means cavities will be larger on the broad contact when compared to the spot contact.

How to contour teeth


After you finish performing IPR with a diamond disc, file the corners with a diamond strip by bending the strip into a "U" shape and holding it that way as you move it back and forth around the corners of the newly created space. You don't want to reduce the main contact area more than neccessary, so make sure the strip is only touching the corners that you want to round off—not the middle of the contact surface.

We offer a complete IPR kit with discs, strips, burs, and gauges. You can purchase the full IPR kit on our online store.

We hope you found this information helpful. Check out our Help Center which is filled with useful information on the topic of IPR and clear aligner treatment.

If you missed any of our previous tech tips, we keep them regularly posted to our blog, which you can find here.

Until next time…

Tech Tip: Variables in clear aligner treatment

When it comes to clear aligners, keeping treatment on track can be a challenge.

There are a number of variables that can affect clear aligner treatment and prevent aligners from tracking the way you intended.

These variables include:

A 2013 study conducted by Chisari et al. and published in the AJODO followed orthodontic tooth movement over time and documented factors affecting tooth movement including age, sex, root length, bone levels, and bone density. Difficult movements such as rotations, intrusions and extrusions were particularly unpredictable.

In the study, clear aligners were programmed to move 1 central incisor 1 mm over the course of 8 weeks. At the end of the study, the mean tooth movement was only 57% of the planned goal. 

Variables image.png

Figure derived from "Variables affecting orthodontic tooth movement with clear aligners; Chisari et al, 2014". The plotted tooth movement is an average of 3 study groups.

Because of these variables (and others), clear aligner therapy can be somewhat unpredictable. Some clinicians will notice discrepancies right away, but a lack of tracking can also accumulate over time.

So, what's the solution?

If you can anticipate potential tracking issues and adjust your treatment goals and techniques accordingly when submitting the case, you can help the required tooth movements track better throughout treatment.

The next logical question then is; "How do I anticipate and manage potential tracking issues?"

1. Monitor:

Check for tight contacts during checkup appointments.

Another thing to look for is the discrepancy between the tooth size (mesial incisal edge to distal incisal edge) and the size of the space that the tooth is attempting to move into. If the space is not big enough, then the tooth will not move adequately into this space and could cause additional tight contacts.

variables 2.png

A solution to this is to prescribe additional IPR or expansion to create adequate space for the tooth to move into, either when you submit the case or in a case revision

2. Revise:

While you and your patient prefer to avoid revisions they are sometimes necessary in order to achieve desired treatment outcomes—especially to acheive difficult movements.

When you request a revision, you can request additional IPR (as was necessary in the example above), engagers, or overcorrection in order to get treatment back on track towards the original treatment goal. 

Depending on the variables affecting your treatment, you may be able to get the teeth back on track without a revision. Here are some articles covering possible solutions:

3. Overcorrect:

Overcorrection is especially likely to be needed for these types of movement:

  • Rotations (particularly single-rooted teeth with roots that have a circular cross-section)
  • Labial-lingual alignment (particularly of incisors)
  • Expansion
  • Extrusion (because the PDL tends to pull the tooth back into the socket)

If your case involves any of these movements, requesting overcorrection when you submit the case can help you acheive your desired treatment goals.

For example, on a case requiring rotations, the doctor could add a note to the case submission form asking for the rotations to be corrected towards the beginning of treatment, and requesting overcorrection to further assist with the rotations.

We hope this information helps you to account for the inevitable variables that can affect clear aligner treatment to achieve the treatment outcomes you and your patients desire. You can find more information on the topic of clear aligner treatment in our Help Center

If you missed any of our previous tech tips, we post them regularly to our blog, which you can find here.

Until next time…

Tech Tip: Impression problems

We recently sent out a tech tip on Impressions - Best Practices, providing tips and instructions on how to take clear impressions.

This tip expands on the subject by providing a comprehensive list of the specific impression problems and procedural errors, their causes and how to avoid them. We will also show you the image of the impression itself compared to its digital model, for increased clarity of each issue. 

Impression problems



  • Description: The complete tooth anatomy and/or gumline was not fully captured by the impression material around it. 
  • Causes: This occurs due to insufficient material in the impression tray. 
  • How to avoid: Make sure you’re using enough material when taking impressions. Too much is better than too little.


Bubbles 2-1.png

  • Description: This is just what it sounds like, it’s an air bubble in the impression
  • Causes: 1. Bubbles occur while the impression material is being distributed, due to the mixing tip being lifted out of the material mid process, creating a hollow void under the material now placed on top. 2. Excessive saliva in the patient's mouth.
  • How to avoid: 1. Keep the mixing tip inserted in the material while dispensing it. 2. Remove any excess saliva before taking impressions. 

Thin walls

Thin walls imp 1.png

Thin walls scan 5.png

  • Description: This is when the material itself captures the majority of the tooth anatomy, however the scanning process does not pick up the tray well, leaving that much of the tooth anatomy incomplete or distorted.
  • Causes: Thin walls are created a number of ways: insufficient material, too small trays or the tray was pushed in too deep. 
  • How to avoid: 1. Make sure you’re using enough material – too much is better than too little. 2. Test the tray in the patient’s mouth. It should extend beyond the most distal tooth. 3. Don’t push the tray into the teeth too hard – you don’t want the teeth to push all the way through the impression material.

Double imprints (aka Shifts)

double imprint 2.png

double imprint scan.png

  • Description: This is when you see two gumlines and/or what looks like two teeth imprints one right next to or on top of the other. 
  • Causes: 1. When the tray, full arch or quadrant is moved during the setting process. 2. If the first-step is not done correctly, for example, when taking the medium/heavy PVS impression and no plastic sheet is used over the first-step impression.
  • How to avoid: 1. Make sure your patient is educated on the importance of not moving their teeth during the impression process. 2. Be sure to use a plastic sheet when taking medium/heavy body impressions on a two-step impression. The plastic sheet will create an impression of the large/rough shape of the teeth (like a custom impression tray).


pulls 3-1.png

Pulls scan.png

  • Description: A “pulled” effect around the gingival margin of the impression.
  • Causes: 1. When the impression material prematurely sets before insertion and results in a “pulled” effect around the gingival margin. 2. When the impression material has not fully set and is removed (pulled) from the mouth too soon.
  • How to avoid: 1. Once you've dispensed the material, put the trays in the patient’s mouth as soon as possible. 2. Leave the tray in the patient's mouth 60-90 seconds longer than the provided instructions.


Tears 2-2.png

  • Description: When the impression material has torn in some way, breaking out of place and undermining the accuracy of the impression. 
  • Causes: 1. Tears occur when the patient has extreme undercuts or black triangles which causes the impression material to lock into the interproximal and tear when removing the impression. 2. Tears can also occur if the material has not fully set before removal.
  • How to avoid: 1. Use wax to block out undercuts before taking the impression. 2. Leave the tray in 60-90 seconds longer than the provided instructions.

Procedural errors

Improper 2-step impressions

Improper 2 step.png

  • Description: When the second step did not bond to first step. In the above image, you can only see the green light-body material on top and you don't see the purple heavy-body mixed. This is how you know that the first and second steps didn't bond.
  • Causes: By using incompatible heavy and light body material.
  • How to avoid: Check heavy body and light body compatibility prior to purchasing.

Insufficient material

insufficient material.jpg

insufficient material scan.png

  • Description: Not enough material was used.
  • Causes: Inadequate measurements of material for the size impression tray used.
  • How to avoid: Too much material is better than too little material.

No light body

no light body.jpg

no light body scan.png

  • Description: No light body was used. The light body and heavy body are usually two different colors, so that they can be identified easily. When the gumlines and occlusal anatomy is not well defined, there will be no sharp details and it will look rounded off.
  • Causes: No light body was used.
  • How to avoid: Be sure to use light body. See our videos on one-step and two-step impression techniques.

We hope this information helps you to take better impressions for the cases you submit to ClearCorrect. Check out our Help Center for more useful information on the topic of clear aligner treatment.

Until next time…

Tech Tip: Best practices for IPR

IPR (interproximal reduction) is a procedure where, by reducing the proximal surfaces of the teeth, a very small amount of space between the teeth is created to allow the teeth to move during treatment. IPR is often reccomended when treating patients with clear aligners.

There are a number of important things to keep in mind when you perform IPR.

Know before you go

  • The amount and location of IPR will be recommended by ClearCorrect, but those recommendations are not absolute.
  • You can let us know how you want to perform IPR (which teeth, when and how, no IPR, expansion, limited IPR, limited expansion, etc.).
  • IPR is always at the discretion of the clinician and it’s up to you to make any necessary changes.
  • Let us know what you want in the IPR and additional instructions sections of the form when you submit your case.

Pre-IPR review by doctor

  • Determine whether to perform the recommended IPR at this appointment. (You may choose to delay some of the IPR until the next appointment.)
  • Determine if pre-IPR separation is needed due to any excessive crowding or rotation. (Pre-IPR separation is when an orthodontic separator, rubber or wire is placed between overlapping teeth to move them apart sufficiently to make room for the IPR disc to fit interproximally. Depending on the amount of crowding, the separator can be left for a few minutes to up to a day or two.)
  • Determine which surfaces of the teeth will be reduced.
  • Determine which intruments and methods you want to use (abrasive strips, single- or double-sided discs, etc.).

Pre-IPR preparation by staffChecking the treatment plan.png

  • When patient is seated for delivery of new aligners, review the treatment setup or the treatment plan sent with the case to see if IPR is recommended at this appointment.
  • If yes, confirm that the patient or parent understands the procedure and has signed an informed consent form.
  • Prepare instrumentation as required by doctor.
  • Identify locations and measurements of the IPR to be performed.

Pre-IPR preparation of the patient

  • Fully explain the IPR procedure to the patient (and the patient's guardian, if appropriate) before beginning.
  • Discuss improbable, but possible, negatives:
    • Sensitivity/discomfort
    • Bleeding gums, lips, or cheeks
    • Feeling of a slight “vibration” on the tooth
    • May feel some pressure on the gums
    • Misshaped anatomy
    • Does not increase possibility of cavities
  • Always get signed consent before performing IPR.
  • Perform any pre-IPR separation of the teeth, if necessary.
  • Apply a small amount of topical anesthetic, if preferred by the patient.

Performing IPR

  • Don’t do IPR where there’s already space.
  • Always check compliance before doing IPR:Checking Compliance.png
    • Check for contact between teeth with dental floss.
    • Contact means patient is compliant (has been wearing their aligners). Continue treatment as planned.
    • No contact means patient is likely not complying. Don't continue with the next step yet. Have the patient wear their current step for another 1-2 weeks and re-check for compliance at the next appointment.
  • Secure safe and adequate access to the IPR site(s):Snap on disc guard tip.png
    • Consider using a disc guard if access is tenuous.
    • Begin with the most posterior sites, working anteriorly.
    • Begin with low RPM until desired angulation is achieved, then increase the RPM to make the reduction.
  • Have your assistant direct an air stream across the IPR site away from your and the patient’s face.
  • Be sure to constantly observe both the labial and lingual aspects to ensure that the teeth are not being cut inappropriately.
  • Use light pressure on the instrument – let the abrasives do the cutting.
  • To perform the amount of IPR indicated on the treatment plan:
    • 1 mm IPR can be achieved with abrasive strips that are 0.08mm (extra fine), 0.10mm (fine) and 0.13mm (medium).
    • 2 mm IPR can be achieved with a one-sided disc that is 0.1 mm thick.
    • 3 mm IPR can be achieved with a two-sided disc that is 0.15 to 0.2mm thick, by gently moving the disc back and forth, mesially and distally in the interproximal space until the desired space is made.
  • To confirm that the contact has been fully brokenstop the instrument and gentlyBreaking Contact.png push it against the gum tissue.
  • When reducing a contact, be sure to break the contact all the way through. The resistance will diminish and the gum tissue will blanch.
  • Confirm interpoximal space created by using an IPR thickness gauge.
  • Idealize the tooth anatomy post-IPR:
    • Angulate the cuts so that they do not disturb the appearance of the tooth.
    • Check the reduced surfaces with an explorer or floss to see if there are any nicks or “ledges” on the tooth.
    • Use diamond burs or abrasive strips to round off any sharp corners.IPR Tracking Chart.png
  • Document IPR performed including the amount and location. You can use the IPR Tracking Chart on our Help Center or place notes directly on the treatment plan or other paperwork.

Following these best practices can help make an otherwise possibly uncomfortable experience for the patient a simple and quick visit before handing out their next set of aligners.

ClearCorrect also offers a number of helpful tools for performing IPR including a full IPR Kit in our online store. Check out all of our IPR tools here.

We hope you found this information helpful. Check out our Help Center which is filled with useful information on the topic of IPR and clear aligner treatment.

If you missed any of our previous tech tips, we keep them regularly posted to our blog, which you can find here.

Until next time…

Tech Tip: Video FAQ about ClearCorrect

ClearCorrect's 2017 Workshops

We're happy to announce that ClearCorrect will be hosting a series of two-for-one workshops in 2017!

If you're new to clear aligners, start with Treatment Basics in the morning and continue with Practice Success after lunch. If you're ready for more advanced techniques, start with Practice Success and follow it up with Advanced Treatment.

Either way, you'll get one session with Dr. Ken Fischer, and another with Dr. Duane Grummons, both orthodontic specialists at the top of their fields.


Request more information

Click the hotel link for information about the hotel. You can also contact an account representative at (888) 331-3323 if you have any other questions about registering.

There are two workshop bundles available: Treatment Basics & Practice Success or Advanced Treatment & Practice Success. You can bring up to 2 staff members at no additional cost, or bring 3 or more for a small additional fee.

We're also offering a 20% discount for those who register prior to 30 days of the workshop date. Enter in the promo code EARLYBIRD when checking out to take advantage of this great offer.

Available Dates

Treatment Basics

Dr. Ken Fischer presents a fast-paced and informative workshop. This workshop is ideal for doctors who have had no previous experience with clear aligner treatment or for doctors looking to refresh their knowledge on the subject. It features demonstrations covering a wide variety of scenarios. The workshop is a PACE approved program offering 4 hours of CE credit upon completion.

Workshop Objectives/Syllabus:

  • Clear aligner/Ortho basics
  • How to select cases for treatment
  • Case examples – simple to moderate cases
  • How to submit a case to ClearCorrect
  • Best practices for impressions & scans
  • Approving and disapproving Treatment setups: technician talk
  • What you need to know about IPR
  • Engagers – what are they and best practices
  • Managing treatment – the basics including revisions & retention


7:30 am – 8:00 am Continental Breakfast
8:00 am – 12:00 pm Treatment Basics
12:00 pm – 1:00 pm Buffet Lunch

Practice Success

Dr. Duane Grummons presents an informative workshop offering tools with step-by-step actions to increase success in your practice. This workshop is for everyone; orthodontists, general practitioners, dental hygienists, assistants and office staff. The workshop is a PACE approved program offering 2 hours of CE credit upon completion.

Workshop Objectives/Syllabus:

  • ClearCorrect and your practice success
  • Doctor leadership inspires teamwork
  • Patient experiences
  • External and internal branding and marketing
  • Thriving (not surviving) in a successful practice
  • Tips and Insights ("secret sauce") shared by master clinician, Dr. Duane Grummons


12:00 pm – 1:00 pm Buffet Lunch
1:00 pm – 3:00 pm Practice Success

Advanced Treatment

Dr. Ken Fischer presents an informative workshop covering advanced techniques and a variety of cases treated with ClearCorrect. This workshop is ideal for doctors who have experience (5 or more cases) with clear aligner treatment or for orthodontists. It features demonstrations covering a wide variety of advanced scenarios. The workshop is a PACE approved program offering 3 hours of CE credit upon completion.

Workshop Objectives/Syllabus:

  • History of clear aligners
  • Mastering troubleshooting techniques for clear aligner treatment
  • Auxiliaries for clear aligners – how and when to use them
  • Case examples – difficult to complex cases
  • Treatment setups for difficult cases: technician talk
  • Finishing cases & revisions


3:30 pm – 4:00 pm Advanced Treatment Reception
4:00 pm – 7:00 pm Advanced Treatment


Dr. Ken Fischer, Orthodontic Specialist

Dr. Ken Fischer has been in practicing as an orthodontic specialist in Southern California since 1975. He is a Past-president of the California Association of Orthodontists and currently serves as a council chair for the AAO.

Dr. Fischer embraced clear aligner treatment in 2000 and has treated a broad spectrum of malocclusions in over 1200 patients. He served on the Invisalign Clinical Advisory Board for 13 years, but now serves ClearCorrect as its Clinical Advisor.

He is the author of a number of published articles, a mentor, domestic and international lecturer, and consultant for clear aligner orthodontic corrections.

Dr. Duane Grummons, Orthodontic Specialist

Dr. Duane Grummons is a Board Certified orthodontist who has lectured before most American orthodontic organizations and world-wide. He has published scientific articles in all major orthodontic journals; an orthodontic/TMD textbook; and many other chapters.

Dr. Grummons is internationally recognized for his efficient and clinically sensible approaches to facial orthopedic, facial asymmetry, TMD management, and non-extraction orthodontic treatments. He is known nationally for his Clear Aligner Therapy innovations and Total Patient Experience lectures emphasizing the Team Approach with staff.

Dr. Grummons is Associate Professor of Orthodontics at The Loma Linda University Medical Center Orthodontic Department. He has appeared before many dental, surgical and medical conferences, and has made radio/TV appearances. His orthodontic specialty practices were in Marina del Rey CA followed by his specialty facial orthopedics/orthodontics and 3D imaging center in Spokane, WA.

He now is busy as a national orthodontics practice consultant, lecturer in Airway Disorders and DentoFacial Orthopedics, and Orthodontic Specialty Management with Inspiration.

ClearCorrect is designated as an Approved PACE Program Provider by the Academy of General Dentistry. The formal continuing dental education programs of this program provider are accepted by AGD for Fellowship, Mastership and membership maintenance credit. Approval does not imply acceptance by a state or provincial board of dentistry or AGD endorsement. The current term of approval extends from 4/1/2015 to 3/31/2019. Provider ID 304173.

Tech tip: Scanning issues

Using an intraoral scanner can increase accuracy and reduce the number of “re-takes”, but imperfections do still happen.

While some of these issues can be cleaned up on our end, it takes some guesswork on the technician's part, and you run the risk of aligners with a less-than-ideal fit.

Here are three of the most common issues you might run into when taking intraoral scans and how to prevent them:

Holes in the scan

holes CEREC.jpg

holes ITERO.jpg

  • Description: Holes through the upper and lower arch scans.
  • Causes: Holes are caused when the intraoral scanner fails to capture the tooth anatomy.
  • How to avoid: To avoid creating holes when scanning, make sure to stay on the tooth long enough so that the full tooth can be captured. Check the scan to make sure no anatomy is missing before moving to the next quadrant.

Missing gingiva

missing gingival carestream 2.jpg

missing gingival TRIOS.jpg

missing gingival CEREC.jpg

  • Description: Minimal material in the gingival region.
  • Causes: Missing gingiva is caused when the intraoral scanner fails to capture the gingival region.
  • How to avoid: To avoid missing gingival areas when scanning, make sure to rotate the intraoral scanner to the gingival to capture the full gingival region and gum line. Check the scan to make sure 3-4 mm of the gingiva is captured, before moving to the next quadrant.

Excess material

excess material CEREC.jpg

excess material CEREC 2.jpg

  • Description: Excess material attached to the teeth.
  • Causes: Excess material is caused when not enough tooth surface is captured, so the scanner software compensates by adding excess material.
  • How to avoid: To avoid creating excess material when scanning, make sure to stay on the tooth long enough so that the full tooth/teeth can be captured. Check the scan to make sure no anatomy is missing, before moving to the next quadrant.

As a reminder, we accept PVS impressions as well as scans from most intraoral scanners.

We hope this information helps you to take better intraoral scans for the cases you submit to ClearCorrect. Check out our Help Center for more useful information on the topic of clear aligner treatment.

If you missed any of our previous tech tips, we keep them regularly posted to our blog, which you can find here.

Until next time…

Tech tip: Intraoral scanning vs. traditional impressions

There are a lot of options out there for capturing dental impressions. ClearCorrect accepts scans from most intraoral scanners on the market, including CEREC,Ormco Lythos3M True DefintionCarestreamiTero3Shape TRIOSE4D PlanScan and Motion View Ortho Insight 3D scanners.

While we happily accept either scans or traditional PVS/VPS impressions, we also know that 3D technology has had a significant impact on dentistry and many doctors are switching to intraoral scanners.

If you're asking yourself whether you should switch, this comparison might help you make your decision:


Intraoral scanning vs. traditional impressions

intraoral_scanning-1.png impressions 2.png

Advantages of scans

  • More comfortable for patients
  • Fewer “re-takes”
  • Less staff time per impression
  • Higher accuracy
  • Minor errors can usually be patched
  • No need to stock expensive PVS material or impression trays
  • No shipping hassles or delays
  • Records can be submitted electronically for faster turnaround
  • $25 discount on ClearCorrect cases
  • 3D models can be stored indefinitely without taking up physical space
  • Digital model can be reviewed in real-time instead of waiting for setup

Disadvantages of scans

  • Accurate results depend on mastering new techniques
  • Some scanning carts take up space in the office
  • Data can be incomplete
  • Upfront integration costs
  • Per-scan or subscription costs for some models
  • Can't be used to pour up stone models

Advantages of traditional impressions

  • Familiar impression-taking technique
  • Minimal upfront integration costs
  • Common, widely-available materials

Disadvantages of traditional impressions

  • Taking high-quality impressions requires practice
  • Impressions must be shipped for processing
  • Fewer conversion steps mean less degradation of quality
  • Higher costs for materials and staff time
  • Space & cost to stock materials & supplies (i.e. impression trays, light body and heavy body PVS, adhesive, etc.)
  • Patients find the process uncomfortable
  • Defects in the impression require a re-take which can be costly in terms of time and inconvenience
  • Impressions cannot be easily patched to fix certain spots, they must be retaken from scratch
  • Defects in impressions are not always visible to the untrained eye

If this is something you've been considering, we hope this information helps you in making your choice. Check out our Help Center which is filled with tons of useful information on the topic of clear aligner treatment.

If you missed any of our previous tech tips, we keep them regularly posted to our blog, which you can find here.

Until next time...

Tech Tip: Best practices for taking impressions

Perhaps the most important aspect of submitting a case with ClearCorrect is making sure that you have clear, accurate impressions or intraoral scans. We thought we’d cover some of the basics on the topic of taking impressions.

From your technique to the material and trays used, there are a number of important things to keep in mind when you are taking impressions.

Best practices

  • PVS or VPS materials work best for impressions. Alginate is not acceptable 
    because it dries out and the material itself can shrink or expand depending on environmental factors.
  • Be sure to use disposable trays and not metal trays – we don’t return tray and when a metal tray is no metal trays.pngreceived, the impression has to be processed manually, which can open the door to potential issues with the aligners.
  • We recommend using heavy body and light body material. Impression techniques that used heavy body and light body seem to get the best results.
  • 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.
  • Dry the teeth with the air syringe to eliminate saliva bubbles interfering with the details of the impression.
  • Be sure to remove all engagers before taking impressions. When impressions areengagers not removed 4-1.png 
    taken with engagers still attached to the patient’s teeth, there is a possibility of the engager tearing the impression when removed and can cause damage to the impression.
  • One-step impression techniques seem to get the best results (but we’ll accept two-step impressions as well).
  • When applying the light body material on top of the heavy body, it is best to avoid lifting the tip of the applicator. This will help prevent bubbles from forming in the impression.
  • The most common mistake when taking impressions is removing the trays when the material hasn’t fully set.
    • timer.jpgSet 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 suggest waiting an additional 60-90 seconds longer than instructed before removing the trays from the patient’s mouth.
  • Another common issue with taking impressions is getting the distal of the last molars—it can be difficult to get a good impression since it’s hard to see back there.
    • Make sure that you’re using a correctly-sized tray. It should extend past the last tooth in the arch without touching the gums.
    • Before inserting the tray containing light body, add some light body directly to the occlusal and distal portion of the last tooth in the arch, ensuring that the last tooth is completely covered with impression material.
  • Once you’ve taken your impressions, before you send them in, take a look at the impression and check the following:
    1. good impression v2.pngMake sure you have detailed, accurate occlusal surfaces. This will ensure that the aligners will have a tight fit.
    2. Make sure all gingival margins are defined and clear. (Includes about 2mm of buccal and lingual surfaces outside gingival margin.) This will ensure enough retention points are present for effective tooth movement.
    3. Make sure that the impression material is intact. Damaged or thin impression material compromises the accuracy of the molds and resulting aligners.
    4. Check that there are no imperfections in the impression material. (Make sure there are no voids, bubbles, thin walls, shifts, double imprints, pulls or tears.) Imperfections or double imprints in the impression could affect the effectiveness of treatment with the resulting aligners.


Insufficient material creates a void in the impression, preventing us from captuing the actual tooth outline.



This occurs while the impression material is being distributed, due to the tip being lifted out of the material. Pulling the tip out creates a hollow void that, when more material is distributed on top of it, creates a bubble.

Bubbles 2.png

Thin walls

Thin walls are created a number of ways: insufficient material, too small trays, or the tray was pushed in too deep. The material itself captures the majority of the tooth anatomy, however the scanning process (performed at ClearCorrect) does not pick up the tray well (where the tray shows through, as in the image below), leaving that much of the tooth anatomy incomplete or distorted.

 Thin walls 2.png


The tray shifted while the impression material was still setting, creating a double margin on a few teeth.

 Shifts 3-1.png 

Double imprints

When the full arch or quadrant was shifted, normally occurring during a two-step impression.

double imprint.png 


When the impression material starts to prematurely set before it's placed in the patient's mouth it results in a "pulled" effect around the gingival margin.

Pulls 2-1.png


Tears occur when the patient has extreme undercuts or black triangles which causes the impression material to lock into the interproximal and tear when removing the impression (to avoid this, use wax to block out undercuts before taking the impression).

Tears 2-1.png

Following these best practices can mean the difference between receiving a good treatment setup with aligners that fit properly or having a difficult case that doesn’t track. Make sure you’re sending in good impressions for your cases and start your cases off right!

And, just as a reminder, we accept digital impressions (scans) from CERECOrmco Lythos3M True DefintionCarestreamiTero3Shape TRIOSE4D PlanScan and Motion View Ortho Insight 3D scanners.

We hope you found this information helpful. Check out our Help Center which is filled with useful information on the topic of clear aligner treatment.

Until next time…

Tech Tip: Gum recession



Gingival (gum) recession is the process in which the margin of the gum tissue that surrounds the teeth moves apically away from the cementoenamel junction, exposing more of the tooth or the tooth’s root. Healthy, attached gingival tissue can only exist in the presence of healthy, supporting alveolar bone; when one or more of the causative factors listed below are present, gingival recession is likely to be observed.


There are a number of factors that can cause the gingival margins to recede, including:

  • Improper tooth brushing with a hard bristle toothbrush
  • Periodontal disease
  • Poor oral hygiene and plaque accumulation
  • Hereditary factors (Periodontal and Gingival Biotype)
  • Intraoral use of tobacco products
  • Clenching or teeth grinding 
  • Traumatic contact between opposing teeth
  • Teeth being moved excessively against the buccofacial cortical bone


Recession & clear aligners

Recession is rarely observed during orthodontic treatment with clear aligners, but the poorly monitored use of fixed braces and auxiliary appliances, e.g. rapid palatal expanders, can result in teeth being excessively moved buccofacially, overwhelming the thin cortical plate of alveolar bone, producing the unwanted recession.

Reducing the excessive pressure as soon as observed may stop the recession, however, once the bone is lost, it will not regenerate sufficiently to replace the lost tissue.

These are situations where gingival grafting to cover the recession may be indicated prior to orthodontic treatment. Consultation with a periodontist is suggested in the management of moderate to severe recession.

Actions to take

When the first signs of gingival recession are observed, it is imperative that the etiology be determined. Is the pathology due to:

  • soft tissue issues,
  • habits,
  • traumatic contacts,
  • or consequential tooth movement?

The initial considerations should be given to the patient’s toothbrushing technique and toothbrush, and confirmed to be in accord with the dentist’s instructions and recommendations for improving the oral hygiene regimen.

In cases where large deposits of plaque have formed, the patient should have it removed as soon as possible.

Extreme recession may need to be treated surgically with a periodontal flap repositioned to cover the exposed roots and interproximal spaces.

Harmful habits

Habitual use of pipe smoking, chewing tobacco, or other caustic agent can irritate the tissues and cause the inflammatory response that leads to potential recession and bone loss. The patient should be advised to discontinue the harmful habit.

Clenching or grinding the teeth together tightly and frequently (bruxism) may be another reason the tissue and bone succumb to the inflammatory response. Nocturnal use of a mouthguard may reduce the damaging enamel wear and associated tissue recession.

Even in the absence of this muscular hyperactivity, an isolated high or traumatic contact between two teeth somewhere in the occlusion may be the stimulant that results in the tissue and bone breakdown. An analytic equilibration to remove the traumatic contacts and balance the occlusion may help soothe the discomfort and allow the tissue to respond positively back to health.

We hope this information was helpful!

Until next time...

Photo credit: Dear Doctor, Inc.