Application Guide

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Crown and Bridge

Printing Strategy for Crowns and Bridges with Castable Materials

Application: Crown and Bridge
Subtype: Castable
Resin: QuraCAST
Layer Thickness: 100 μm
Software: Alpha 3D

 

Dental Model Orientations

Dental models may be printed a number of different ways:

A. Horizontal: Accurate, requires the least print preparation time, and prints the fastest for individual prints, but takes up the most build platform space

B. Angled (10-15°): Highest possible accuracy and smoothness, but requires the most print preparation and support cutting time

C. Vertical: Fastest printing method for mass production, but slowest for individual prints

When should I print angled?

The angled orientation is best used when accuracy and smoothness are more important than the time invested to make the print. For example, when aesthetics are important, such as when prints are going to be attached to articulator interfaces and shown directly to patients, then it may be better to print at an angle.

When should I use a different orientation?

In general, the angled orientation takes the most work to set up and to print. The horizontal orientation is not as smooth and may encounter resin leakage holes, but generally meets most accuracy needs without the set up time. More models can be printed in less time with the vertical orientation. If your prints are being used in the lab setting, either other orientation may suit your needs better.

1. Print Analysis

A. Critical Areas – Do Not Add Supports

  • The most important part of this print is the fitting area of the crown and bridge against the part or abutment. Therefore, the crown must be in a position where the fitting area is facing away from the build platform.

B. Intended Support Area

  • If the fitting area is facing up on the model, the tooth surface should be facing the build platform and will therefore be the support surface. This means more work is necessary to make it look better, but this is easier to do than manually adjusting the fitting.

2. Orientation

  1. Put the model in a horizontal position and make sure the fitting area of the abutment is facing upwards.

    It can be difficult to make it flat because it is all tooth surface area at the bottom. It does not need to be perfect. Your goal is to avoid putting supports in the fitting area.

  2. Raise the model off the build platform.
    • You can automatically raise the model when you add the supports. Open the Supports panel, and set the height parameters.
    • Support Height: 1.5 – 2.0 mm

Note

The model and print area shown in Alpha 3D is actually inverted on the printer. It is easier to see and work with your model in this perspective, but the object is printed from the bottom up during the print process.

3. Supports

When adding supports to the model, we recommend the following procedure:

  1. Open the Supports panel, apply the settings as shown below, and click the Auto Support button to add supports.
  2. Click the Manual Support button and remove any supports that are too close together.
  3. Add supports to any areas that have too few supports.
  4. Change the support settings to be the same as the Base Support settings as shown below.
  5. Remove all supports at the lowest points of the print.
  6. Add more manual supports (with the Base Support settings) to the lowest points of the print to make sure that area is securely attached to the build platform.

Note

You must select an object to add supports to that specific model. You cannot use the Auto Supports or Manual Support functions with all models at the same time.

Tip

Use the View Slider function to identify the lowest points of the print.

Support Area

Support Results

4. Base

We strongly recommend adding a base to your model because it allows the print to securely attach to the build platform. A base also makes the print easier to remove during processing.

  • If you use select General on the Type dropdown list, Alpha 3D automatically adds a small base to every support. These small bases are sufficient for most prints.
  • You can also key in a value for the Base Thickness setting to add a base around the entire print. This makes it easier to remove the print from the build platform.

Warning

A thicker base does not improve print performance. A Base Thickness of 0.400 mm or thicker can make a print less likely to succeed.

5. Printing

Put all of the models that you want to print in place.
Then, click the Printing Setup button to open the Printing Setup window and make sure the settings are as follows:

  • Your printer is selected on the Printer Model dropdown list.
  • QuraCAST is selected on the Material dropdown list.
  • Select your Layer Thickness. We recommend a layer thickness of 100 micrometres.

Click the Print button to open the Print window and save your model as a print file. The top of the window shows your Printing Setup settings.

  • Key in a Job Name.
  • Click the Save button to save the name and settings.

Alpha 3D slices the model into layers and creates the print file. When the process is complete, it shows the IBF file in a window. You can now send this IBF file to your printer and start the printing process.

6. Finishing

When the printing process is complete, you must clean, dry, and remove the print supports.

  • Cleaning Alcohol: Ethyl alcohol (95%)
  • Ultrasonic Cleaner or Soak Time: 2 minutes

Note

It is not necessary to cure this resin in a UV oven after printing.