Split-cast and magnetic plates for 3D printed models
How 3D printed models go into a physical articulator: split-cast plates, magnetic plates, printable articulators and model bases, compared for the dental lab.
A 3D printed model does not go into an articulator on its own. Between the model and the articulator there is always an interface: plaster, a plate, or a printed joint. The choice decides how repeatable the position is, how long mounting takes and how much the result depends on the printer. This post is for labs moving from stone to 3D printed models, and it compares the main options.
Plaster on printed models
Printed models can be mounted with plaster like stone models. It works, and labs with many mechanical articulators often start this way. It takes time, the plaster expands, and the position comes from the hand of the person mounting. The virtual position in exocad and the physical one are then two separate things.
Split-cast bases
A split-cast base has a keyed interface between the model and the articulator plate. The model can be removed and put back in the same position. In a digital workflow this keyed shape is designed into the printed model base in Model Creator and matches a plate on the articulator. The position is then defined by the software rather than by the plaster.
Magnetic plates
Magnetic plates hold the model with a magnet, often in combination with a keyed interface. The keyed interface gives the position and the magnet keeps it there. They make mounting and removal quick, which helps when models go back and forth between the articulator, the bench and the scanner. Magnets must sit flush: a magnet slightly proud of the surface lifts the model.
Printable articulators
Printable articulators skip the mechanical articulator. The joint is printed with the model and reproduces movements from fixed values built into it. exocad offers xSNAP for this, an add-on library for Model Creator with joints for several condylar inclinations. Printable joints are simple and cheap per case. They are limited to the values printed in, and they depend fully on the printer accuracy.
Comparison
| Option | Repeatable position | Time per case | Depends on printer | Adjustable values |
|---|---|---|---|---|
| Plaster mounting | Low | High | Little | Yes, on the articulator |
| Split-cast base | High | Low | Yes | Yes, on the articulator |
| Magnetic plates | High | Low | Yes | Yes, on the articulator |
| Printable articulator | Medium to high | Very low | Fully | Fixed in the print |
Choosing a system
The most practical choice is usually a plate system that exists as an exocad library for the articulator the lab already owns. The bases are designed in Model Creator, the position is the same as in the software, and no new articulator is needed. RotoClick is one such system, combined with a facebow digitized at the clinic.
Whatever the system, two conditions apply. The printer must be calibrated, since every plate depends on its dimensions, and the articulator must be calibrated against the system. The post on articulator calibration for printed models explains both. The Model Creator guide covers the model design itself.
Labs that want printed models with the right bases without setting up the printing themselves can order them through the 3D printing service.
One magnetic plate system with libraries for exocad, 3Shape and Blender for Dental is described in DACOS for printed models.
Frequently asked questions
Can printed models be mounted with plaster like stone models?
Yes, and it still works for single cases. It adds plaster, time and a step where the position can change, which is why most digital labs move to plates designed into the model base.
What is the difference between split-cast and magnetic plates?
A split-cast base has a keyed interface that lets the model be removed and put back in the same position. Magnetic plates add magnets to hold it. Many systems combine both, a keyed base for position and a magnet for retention.
Are printable articulators accurate enough?
For many restorations they are. They reproduce movements from fixed values printed into the joint, so they are simpler than a mechanical articulator with adjustable settings. exocad offers xSNAP, a printable joint for Model Creator, as an add-on.
Which option fits a small lab?
A system whose plates are available as an exocad library for the articulator the lab already owns. It avoids buying a new articulator and keeps the position defined in the software.