Treading new paths
Without doubts CAD/CAM procedures have changed the way dental technicians think and work, these tools not only give us more control over our work, they also help us to think outside the box.
Today it is no longer surprising for the technician to choose monolithic zirconia for crowns and bridges in daily practice. The development of new materials is progressing extremely fast and offers more translucent and resistant materials that allow the indication ranges to grow exponentially. It is our responsibility not only to use the benefits of these tools to improve our work, but also to bring us closer to nature.
Achieving natural shape and texture
In every laboratory you will find countless natural models from previous works. This can be an antagonist, a study or a working model from which we can simply copy the natural anatomies.
After digitizing the working model, in this case a mandible with five implants, we select a prototype model form our scanned “model library” (antagonist, study or work models from previous cases) that better fits the case. In the expert mode we import the selected model as a “pre-op model”, of course it is difficult to find a natural model that adapts perfectly to the current situation. Fortunately, the Ceramill Mind Design software offers the ability to “Allow Resizing” (Fig. 1) in the “Add/Remove Mesh” window to do this job.
The mesh from the prototype model is trimmed to enhance the adaptation of the “custom” or preloaded anatomies. After the anatomies were copied with the “Adapt to Pre-Op Model” tool (Fig. 2) we can do the fine tuning of the position in association with the model and the occlusion.
After achieving the final positioning of the tooth, we proceed to accomplishing the gingival component. To do this, we again import the prototype model to design the gingiva naturally. This part needs to be done with the “Free Form” tool and the prototype mesh to get a natural appearance (Fig. 3).
After completing the gingival component, it is useful to make a printed test of the rehabilitation to check the function and esthetics in the patient’s mouth.
The perfect red-white esthetics
Once the clinical corroboration of the prototype has been completed, we can begin with the final adjustments of the restoration. It is my preference, for this type of restoration, to design the tooth monolithically and veneer the gingiva part. For this purpose, we reduce the gingival component (Fig. 4). Again, we have the prototype to ensure a more natural design of our gingival structure, and we have a natural model that serves as a reference for the final anatomical appearance of the veneered gingiva.
In order to use this type of workflow, it is necessary to have a system that perfectly matches the CAD design with the final milling output (CAD design / CAM calculation / CNC process (Fig. 5+6)). Therefore, the post-processing and final adjustments in the green state are minimal, only details to preserve the natural anatomies (Fig. 7) from the natural prototype are necessary.
HD (high definition) processing is exactly the right strategy for this kind of restoration. The 5-axis strategies ensure consistent results with minimum post-processing. After milling, coloring Zolid HT+ White with Ceramill Liquids “New Formula” is a simple process and enables esthetic results in a few minutes (Fig. 8).
I still remember every time I faced this kind of restoration- and the amount of time I needed to achieve natural results. The CAD/CAM technology has not only given the dental technician the opportunity to perform high-quality work in a short time, but also opens endless possibilities.
The dental technician must be aware that there is no better master than nature. Today we have the tools and the beautiful materials to achieve this.
Tue. 27 April 2021, 4:00 PMLight Management with Zolid HT+
Smart choice of framework material for full color control.