3D Printing Dental Models For Clear Aligners/Retainers & Indirect Bonding Trays

Data Capturing 

In order to print the dental model, the patient’s impression must first be captured digitally. This can be accomplished with intraoral impression scanners, desktop impression/model scanners, or via CBCT impression/model scanners. ​

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Design and Treatment Planning

It is always recommended to clean the excess gum and cheek portions of the intraoral scans for best results:

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Raw scan automatically fixed in RayWare:

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Out of Office Occlusal Guard Design


SprintRay Cloud Design helps and provides aligner/retainer model design, where you can upload patient’s scan files and your prescription. Once you receive the STL file of the designed models from SprintRay Cloud Design, printing can proceed

 

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In-Office Designing 
This is done in a dental model CAD software. SprintRay Software allows you to choose a dental model software that best meets your clinical needs. Our software accepts any design file formatted in STL, which means you can use whichever software you are most comfortable with: 3Shape Splint Studio, Exocad, Magics, D3splint. Once the scans are imported to the design software:

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Printing - Special Considerations

Almost all orthodontic models will be created with flat bases, so therefore should be placed flat horizontally on the build platform with the occlusal surface facing upwards.

 

For the best accuracy and speed, it is not recommended to print models vertically. Vertical models are much more prone to print failure due to unsupported surfaces and "islands" that can be formed due to mouth anatomy. Vertical models are also less accurate than models placed flat on the build plate due to the way the projector optics work in the X and Y dimension

 

In most cases, 100µm Layer Thickness should be selected for recommended print times and accuracy:

 

Retainer or Aligner model:

 

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Issues to be aware of:

 

Model angulation - teeth should be perpendicular as possible to the platform to allow the appliance to lift straight up and off of the printed model

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Model Height - models should not be taller than 25 - 30mm, as this will cause the plastic to stretch too thin and result in inaccuracy/distortion

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Bad or Dirty Scans - models that need to be trimmed in a design software, or are missing critical data. Missing data could also be a damaged plaster model that has been scanned as well

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Deep Undercuts/Interproximals - deep gingiva margins, or large undercuts near the interproximals will results in appliance deformation during removal, and must be properly blocked out with wax before thermoforming

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Indirect Bonding Trays

 

Indirect bonding trays should also be placed flat on the platform. Due to the flexible nature of IDB materials, printed models should always have a flat base, with no supports:

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Post Processing

Models should always be post processed per the recommendation in the resin Instructions For Use (IFU).

  • For SprintRay Die & Model and IDB resins, Isopropyl Alcohol with a purity of 91% or higher is required for the washing process, per the FDA.
  • If cleaning more than 2 or 3 models in the Pro Wash/Dry, longer wash and dry times may be necessary for best results.
  • Always ensure models are completely clean before post curing in the Pro Cure units, and always select the correct profile for the resin being used.

 

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Appliance Creation

Models for Aligners/Retainers:

After post processing the models for retainers or aligners, the models have appliances created using a thermoform method, also known as a suckdown.

Before creating the suckdown, the models are prepared using a method known as wax blockout. This is where wax or a UV filling material is applied to the model to reduce the undercuts and overhangs of the tooth anatomy and allow the appliance to be removed from the model without distortion. This process can be done digitally in the model design software by extruding tooth surfaces for smooth transitions, or done manually by hand by adding melted wax or UV curable filling material:

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After any necessary wax blockout is performed, a non-stick separating medium is coated on the models, then they are placed on the thermoforming machine for appliance creation via thermoform.

 

The plastic is allowed to cool, then trimmed away from the model into an arch shape, then washed and placed in the patients mouth to either retain teeth, or slightly move them until the next aligner is needed. ​

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Note: removal of the plastic thermoform from the printed model is one of the leading causes of appliance distortion! The plastic should always be allowed to cool to room temperature, plastic should be as trimmed as possible, and care should be taken not to deform the appliance during removal from the printed model.

 

If any minor distortion of the appliance occurs (i.e. the posterior portions of the appliance do not fully seat on the teeth), then the appliance can be made slightly pliable with warm water or a steamer for delivery to the patient:

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Indirect Bonding Trays (IDB):

Once the Indirect Bonding Tray is printed and successfully post processed, the bracketry for the traditional style braces is placed in the model for each corresponding tooth position:

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Once the brackets are placed, the tray is cleaned and prepped for placement in the patients mouth:

 

 

 

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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