Calibrating for Aligner/Retainer Fitment - Best Steps to Success

Calibrating your printer for the best retainer or aligner fitment is important for accurate movement and/or retention of the teeth, and critical for patient comfort and care.

 

Following this guide, you can calibrate your Pro or MoonRay printer for the fitment required by your practice or lab. It is important that the steps are followed in the order shown for a step by step approach.

 

For best results, it is ideal to have a scan or model of your own mouth, or a willing lab tech/assistant that can verify the fitment before printing live cases.

 

Note: Fitment of aligners and retainers can be very subjective. In general, we try to calibrate fitment for aligners to be more "active", or tight, for teeth movement, and retainers tend to be more "passive" or loose. As noted above, it is best to have a willing test subject to check fitment with a retainers/aligners created on the test models during the calibration process

 

Tools Needed:

 

  • 91% or higher Isopropyl Alcohol for washing models
  • Platform scraper
  • ProCure, or similar, UV post-cure oven
  • Digital Calipers
  • Test Dental Model/Arch for checking aligner/retainer fitment

 

Before Proceeding

Please ensure that the material that is being calibrated is well mixed, and that the glass surfaces on the printer are completely clean and spot free. It is critical that all optical surfaces are free of any streaks, smudges, dust, resin, or fingerprints.

Baseline Calibration

The first steps are to create a baseline calibration before proceeding. We want to ensure that the projector intensity, as well as the X and Y scaling are as close to factory specifications.

1. Perform the Fit and Tolerance calibration via the Material Fine Tuning menu in RayWare. This calibration has the greatest effect on the fitment of the aligners/retainers around the teeth themselves, and this will ensure that the printer's Projector Intensity is calibrated to the correct level. This settings is comparable to the brightness setting on a TV; it does not affect the distance from molar to molar, only the localized brightness of each layer. This is the setting that we will most likely need to adjust later. Here is an example below with a single layer from a standard dental arch:

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Projector intensity at a 5:

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Projector intensity at a 1 or 2:

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Note: changes to layers/images exaggerated to show a clearer example

 

 

Begin the calibration by going to Print > Fine Tuning > Material Fine Tuning

 

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Make sure you select the same Material and Layer Thickness that you want to calibrate:

 

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Then select Fit and Tolerance:

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Print the calibration model, clean, and post cure using the same method as your models

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Do not proceed until you have achieved a 3 score, as this test is crucial to establish a standard light level for the projector. A 4 or 5 rating indicates the projector is under-curing, while a 1 or 2 rating indicates the printer is over-curing (or the glass/optics are dirty):

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2. The next step is to perform the Dimensional Accuracy calibration to dial in the machine's X and Y scaling. This setting affects the molar to molar distance, or the distance from the center line of the arch to the teeth. This adjusts fitment of the entire aligner/retainer, such as the "squeezing" from the outside inwards, or pressure from the inside outwards. This setting is comparable to adjusting the screen size of a TV:

 

                           Before adjustment                                                               After adjustment

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To perform the Dimensional Accuracy calibration, select in the same Material Fine Tuning menu we used for the Fit and Tolerance test. Make sure you select the correct Material and Layer Thickness:

 

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Select Automatic Calibration:

 

 

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Once printed, clean and post cure using the same method as your models. Then take an accurate measurement using the Digital Calipers down to the second decimal place in Metric. It is normal to have a +/- X/Y tolerance of 75-95µm, or +/- 0.075-.095. Press Finish once the values are entered:

 

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3. Perform a test print with a dental model that you can create an aligner/retainer on and check fitment, whether it be on a willing test subject, or a study model. 

At this stage, we are printing models as close to 1:1 as possible, and in most cases, the fitment is OK for aligners, as a tighter fitment is desired. If the fitment meets your standards, you can proceed with normal printing.

If you would like a looser fit, proceed to the next step.

 

Adjusting for Your Desired Fitment

Now that we have established a baseline calibration, and are printing as close to 1:1 as possible, we can make further adjustments to dial in the fitment.

Note: this step will require minor adjustments, and then printing one model to verify fitment, and may take a few prints to dial in, depending on your fitment needs.

If your models are too tight:

Go to the Material Fine Tuning menu and select the Fit and Tolerance test for the Material and Layer Thickness we are calibrating. Do not print the test. We are going to Skip the Print:

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On the next screen, input a 4 score and press Finish:

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Now re-print the dental test model, clean, post-cure, and re-check the fitment. If fitment is still too tight, re-enter another 4 score into RayWare and re-run the dental test model until desired fitment is achieved.

 

If your models are too loose:

Perform the same steps above, but enter a score and reprint your dental test model until desired fitment is achieved.

 

Alternate Methods to Achieve Desired Fitment

 

Manual Scaling for each model

You can also manually scale the models by small percentage values using the Scaling tool in RayWare:

Select a model, then enter a Scaling value of 99 to 101%

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Force a Scaling Value for All Prints

 

Go to the Material Fine Tuning menu and select Dimensional Accuracy, then select Manual Calibration:

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Then enter the desired Scaling Factors you wish to be applied to all prints for this Material and Layer Thickness:

 

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Print your dental test models and verify fitment.

 

 

If you are still having issues with getting your model sizing calibrated successfully, please contact our Support Department at 800-914-8004 and we can help you with any issues.

 

We can help with that!

If you're experiencing difficulties or have questions about any of your SprintRay products, submit a support ticket or contact us at 800-914-8004

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