Application Guide

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Crown and Bridge

Application Guide for Printing Castable Materials

Application: Crown and Bridge
Subtype: Cast
Resin: QuraCAST
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 Support

  • The most important part of this print is the fitting area of the crown and bridges against the model or implant attachment. As such, the crowns should be positioned so that their fitting area is facing away from the build platform.

B. Intended Support Area

  • If the fitting areas are facing up, then the tooth surface should be facing the build platform, and therefore will be the support surface. This does mean that a lot of additional aesthetic work will be necessary, but it is easier to do this work than to manually adjust the fitting.

2. Orientation

A. Position the print as horizontally as possible, with the fitting area of the die facing upwards.

There will be a lot of tooth surfaces on the bottom, and it may be hard to make it flat. It does not need to be perfect; your goal is to just make the fitting area not require supports.

B. Raise the part off the platform.

  • In Alpha 3D, you raise a part along with setting up its supports. Go to the Supports tab, and set the height in the parameters.
  • Support Height: 1.5 – 2.0 mm

3. Supports

When supporting this print, Ackuretta recommends the following:

  • A. Set up the support parameters shown to the right.
  • B. Use Auto Support to add the majority of the supports.
  • C. Go to Manual Support, and use the slice slider to find the lowest points of the model. Make sure that supports are on those points. If multiple supports are very close together, you can remove redundant supports, as long as at least one is on the lowest point.
  • D. Add more supports along the bottom of the crowns to make sure that they are strongly affixed to the build platform.

Support Area

Support Result

4. Base

Ackuretta recommends adding a base to almost all supported prints. Adding a base allows the print to stick to the build platform securely, and it makes the print easier to remove during post processing.

  • If you use the General support setting, Alpha 3D automatically adds a small base to every support. This small base is sufficient for most prints.
  • Additionally, you can add a base around the entire print using the Base Thickness setting. This may make it easier to remove the print from the build platform.

Warning

A thicker base does not improve print performance. A base of 0.400 mm or thicker may even make a print less likely to succeed.

5. Print

Arrange all of the models that you want to print, and then go to the Print tab.

  • Select your Layer Thickness. Ackuretta recommends 100 microns.
  • Give your print a Job Name.
  • Click Save.

On your printer, make sure that your settings match what you need for your resin.

Diplo / Ackuray Print Settings

  • Buffer Layers: 6 layers
  • First Layer Curing: ×9

FreeShape 120 Settings

  • Burn-In Layers: 6 layers
  • Burn-In Layer Curing Time: ×10 curing time
  • Z-Axis Peel Speed: 900

6. Finishing

After printing, clean, dry, and cut your print supports.

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

Note

Do not cure this resin further in a UV oven after printing.

7. Casting

Use the following casting burnout schedule for casting your crowns and bridges.