exocad virtual articulator and jaw motion: a practical guide
How the exocad virtual articulator and Jaw Motion Import module work, when dynamic occlusion matters and how to transfer a physical articulator setup.
A restoration can have perfect contacts in maximum intercuspation and still interfere as soon as the patient moves the jaw. The exocad virtual articulator shows those interferences during design, before the restoration reaches the mouth. It is an add-on module and together with Jaw Motion Import it covers everything from average articulator values to movements recorded on the patient. This guide explains both modules and when dynamic occlusion is worth the extra steps.
Static and dynamic occlusion
Static occlusion is the set of contacts in maximum intercuspation, which is what the basic design shows. Dynamic occlusion is what happens in protrusion, laterotrusion and every movement in between. Cusps that fit well in intercuspation can collide with the antagonist during these movements.
For many single units on a stable dentition, static contacts are enough. Dynamic simulation matters when the restoration takes part in guidance or changes the occlusal scheme.
The Virtual Articulator module
The exocad Virtual Articulator brings dynamic occlusion into the design. Like a physical articulator, it works with parameters such as condylar inclination, Bennett angle and lateral shift, using average values or values from the patient’s records.
During design you can simulate the movements and see where cusps interfere. The module can also generate a movement envelope, so the anatomy is shaped inside the space the antagonist leaves free and occlusal surfaces are corrected before production instead of being ground chairside.
With a compatible scanner, the position of plaster models mounted in a physical articulator can be transferred to the software, which keeps the jaw relation the clinician recorded.
The Jaw Motion Import module
Average articulator values are an approximation. Jaw Motion Import brings in the patient’s real movement, recorded by external devices. exocad lists sources such as Zebris JMA, Modjaw, SDI Matrix, OXO, ITAKA and Gamma CADIAX and the module works together with the Virtual Articulator. Combined with the Model Creator module, recorded motion can also be used to produce semi-dynamic physical models.
When dynamic occlusion is worth it
| Case | Static contacts | Virtual articulator | Recorded jaw motion |
|---|---|---|---|
| Single posterior crown, stable occlusion | Usually enough | Optional | Rarely needed |
| Anterior restorations involved in guidance | Insufficient | Recommended | Useful |
| Multiple units, quadrants | Insufficient | Recommended | Useful |
| Full-arch, implant bridges | Insufficient | Recommended | Very useful |
| Splints, changes of vertical dimension | Insufficient | Recommended | Very useful |
Designing with the virtual articulator
- Collect the bite registration and, when available, the articulator values or a jaw motion recording.
- Align the models carefully. A wrong bite, or a scanned registration with material between the teeth, invalidates every later step.
- Choose the articulator type and values consistent with what the clinician uses.
- Design the anatomy first, then run the movements.
- Remove interferences in the movement simulation as well as in static occlusion.
- Check the thickness again, since removing interferences can take the material below its minimum.
Physical articulators and transfer plates
Several manufacturers offer mounting plate systems that make the transfer between physical articulator, scanner and CAD repeatable. In labs that still mount models they save a lot of time. They work only when the whole chain is compatible: articulator, plates, scanner calibration and exocad configuration. Verify the combination before buying, then calibrate it.
How the models get into the right place before any movement is covered in digital facebow in exocad and one system that links a facebow taken at the clinic to printed models is described in RotoClick in exocad. The interfaces themselves are compared in split-cast and magnetic plates for printed models.
Common errors with the virtual articulator
Average values are a poor fit for a patient with very particular guidance. A wrong bite registration makes the whole occlusal design wrong, however carefully it is done. Running the articulator only at the end, when the anatomy is already fixed, turns small corrections into large ones. And a movement recording belongs to one specific model position, so it cannot be reused after the models are realigned.
For splints, where dynamic contacts are the main purpose of the design, see occlusal splint design in exocad. For full dentures, see digital dentures in exocad. When the scanned bite itself looks wrong, Bite-Finder is one tool that corrects it before the design starts.
Frequently asked questions
Do I need the virtual articulator for every crown?
No. For a single posterior crown in a stable occlusion, static contacts are usually enough. The articulator becomes important on multiple units, anterior guidance, full-arch work, splints and changes of vertical dimension.
What is the difference between the Virtual Articulator and Jaw Motion Import modules?
The Virtual Articulator simulates movements from articulator parameters such as condylar inclination and Bennett angle. Jaw Motion Import adds the patient's real recorded movements from compatible devices and works together with the Virtual Articulator.
Which jaw tracking devices work with exocad?
exocad lists devices such as Zebris JMA, Modjaw, SDI Matrix, OXO, ITAKA and Gamma CADIAX among the supported sources. Check the current list for your exocad version.
Can a mounted plaster model be transferred into exocad?
Yes. With a compatible scanner and articulator setup, the position of the models in the physical articulator can be transferred to the software.