Preparing dental scans for printing with Scan to Model (Form 2/Form 3B/Form 3BL/Form 4B/Form 4BL)

Intraoral scanning equipment captures digital impressions of the mouth to form a high-detail 3D scan, but they often create incomplete meshes or uneven bases. These become problems in SLA printing because:

• Non-manifold meshes do not form a complete, watertight object and generally have missing pieces. PreForm offers to repair these models when they are imported. Some tools within PreForm will be unavailable for unrepaired models, including Hollow and Label.
• A level surface is needed as a base in order to adhere to the build platform and reduce post-processing work.

The Scan to Model tool removes extraneous data from the scan and creates a flat base.

Step 1: Open Dental Workspace

PreForm version 3.29 or later features a Dental Workspace tailored to dental workflows. This workspace helps you automate the setup of common dental applications and also includes Scan to Model.

When opening PreForm version 3.29 or later for the first time, a menu labeled Choose Workspace appears.

Select Dental Workspace. The Dental Workspace homepage appears.

To access Scan to Model, click the X in the top-right corner of the Dental Workspace homepage. The 3D scene appears.

Click the tooth icon in the left toolbar to open Scan to Model.

Step 2: Import the scan into PreForm

PreForm is compatible with STL, OBJ, FORM, and 3MF files. Save your scan as one of these file types to open it in PreForm.

To import the scan:

1. Open PreForm.
2. Click the < button. The Job Setup dialog box opens.
3. Click the printer name. If a printer is not selected, click No Printer Selected. The Job Setup window opens.
4. If applicable, select a preset.
5. Under Choose a template, select a printer type. Scan to Model is only available for printers that can print with materials for biocompatible applications.
6. Scroll down to the Choose Material section. Hover your cursor over your desired material to view the available versions for that material. Select a material and version.
7. Scroll down to the Choose Layer Thickness section. Click to select a layer thickness. For diagnostic models, Formlabs recommends 100 microns.
8. Click Apply. The selected material and layer thickness settings are applied and the 3D scene appears.
9. On the left toolbar in the 3D scene, click the tooth icon to open Scan to Model.
10. Click Import.
11. Select the STL, OBJ, or 3MF file you wish to open.

Step 3: Orient the model

PreForm automatically orients the model following best practices for printing dental models. If you need to change the orientation, use the sphere manipulator to position the digital impression so that the occlusal surface faces away from the build platform.

To manually orient the model:

1. Use the sphere manipulator to position the digital impression so that the occlusal surface faces away from the build platform.
2. If you changed the model’s orientation, click Next. Otherwise, PreForm automatically continues to the next step.

Step 4: Trim extraneous data

PreForm automatically sets the Trim Plane Position to the height required to remove unnecessary parts of the scan from the bottom of the model.

To adjust how much of the model is trimmed:

1. Drag the Trim Plane Position slider to move the trimming plane.
2. Review by rotating the view around the part to ensure important anatomy is not being removed.
3. Click Next.

Step 5: Add a base and hollow the model

Use the Base Height slider to create an even base that adheres to the build platform and allows for easier removal. You can also hollow your models to decrease material usage and save time.

To add a base and hollow the model:

1. Drag the Base Height slider to add additional height to the model's base. A base is added below the trimming plane.
2. Select the Hollow model checkbox to hollow out the edited model. If you select this option, PreForm automatically generates honeycombing and creates drain holes so that liquid resin can flow out of the model.
3. Click Create. The base is generated and the model is hollowed, depending on the selected options.

Step 6: Support, rotate, or print directly on the build platform

Once the model is built, it is ready for printing. You may print the model directly on the build platform, add supports, or rotate for near vertical printing.