Category: Milling

The following case demonstrates how a symptomatic cracked tooth was treated with an emax restoration that was fabricated / seated during the same appointment as it was prepared. The patient had a heavy gag reflex and the preparation and access were difficult. The medit i500 was utilized and the restoration was designed with CAD-Ray’s design software, powered by exocad, and then milled with the Z4 milling machine by VHF

In this pre-op of video, trans-illumination was utilized to highlight the lack of light propagation at the crack line. Moreover, the patient was percussion sensitive on the lingual cusps for over 5 days where he initially developed symptoms

The Medit i500 software was launched while the patient was anesthetized. The appropriate job definition was defined where we identified that a pre-op scan would be taken. We also identified the spacer parameters and the marked the opposing dentition. All of these items define the image catalog that will be launched when we capture the optical impression (there will be a preparation model, a pre-op model, the opposing, and minimally one bite registration)

While anesthetic was taking affect, salt on the tongue was used to suppress the gag reflex, and the opposing arch was imaged. Then the lower arch was scanned and the bite was captured. The software then was set to the mandibular arch where the tooth in question was cropped out of the equation.

A great benefit to this approach is that you can analyze if you have taken the bite registration correctly before you even image the preparation. Sine the medit i500 can capture color, you can can the patient bite down on articulating paper and pick up the color renderings while imaging. You can then compare the digital occlusal stamps to the ones left behind by articulating paper. This is a great way to gauge if you or the patient has introduced errors in the capturing the correct occlusal relationship between the upper arch and the lower arch

Since the patient was very sensitive while taking impressions of the tongue, the model of the preparation was built in multiple segments and steps. With the medit i500, the initial part of the preparation was imaged, certain areas were cropped out, then the tip of the camera was used to displace the tongue so the lingual margins could be captured. The image itself was capture in the local HD mode. The attached video demonstrates how areas were protected with the software so that we did not inadvertently introduce errors to areas that already had accurate data captured

Once the image was captured, it was processed and directly launched into CAD software. the pre-existing condition was replicated in the design of the crown and minor adjustments were made to its morphology while taking the opposing dentition into consideration

Once the restoration was designed it was automatically transmitted to the milling machine for fabrication. After it was milled, the restoration was checked for fit and contacts while in its blue stage and then crystalized in an oven. Once cooled it was seated with resin cement.

The Meditlink software has a Work File List that is maintained after you have finished your design. It hold the arches, the occlusion, the restoration stil file and the dentalCAD file that you can relaunch to either continue with a previous design or launch a whole new design

It i sometimes confusing to some doctors when looking at bitewings shot at specific angles that make the margin look like it has filled in with resin, or the the margin is “raised” with composite material.  When looking at a sloping margin, where you have a deep chamfer or finish line, instead of a shoulder margin, when you take a bitewing immediate post-op X-ray, the flow of the margin line is superimposed on itself due to the two dimensional image.

Clinically, if you look at the margin design, you will appreciate the anatomy of the prep and how that can lead to this effect.

This is a lesson in chairside efficiency for all CAD/CAM users. Traditionally, you would be forced to prep two teeth and impress them both at same time, but with digital dentistry, you can break the case up and do it in segments, as if they are two separate patients involved.

In this particular case, the restorations were designed, milled, and seated in a single appointment.  To speed things along, only the second premolar was addressed; it was prepared, imaged, designed and milled.  While milling, the second molar was prepared.

After the tryin, they were chrystalized and seated at the same time.  Leveraging preparation time with mill time of multiple units can greatly increase efficiency at chairside.  See the following videos to pick up on all the details of the case.

CASE SET UP FOR PREMOLAR SCAN IN MEDIT

REMAINING TOOTH STRUCTURE AFTER REMOVAL OF PREVIOUS RESTORATION AND PREPARATION REFINEMENT

PREMOLAR DESIGN IN EXOCAD

REMAINING TOOTH STRUCTURE AFTER PREVIOUS CROWN REMOVED AND THE PREPARATION REFINEMENT

CASE SET UP FOR MOLAR IN MEDIT

MOLAR DESIGN IN EXOCAD

TRY-IN OF EMAX PREMOLAR

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TRY-IN OF EMAX MOLAR

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SEAT OF PREMOLAR AND MOLAR EMAX CROWNS

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IMMEDIATE POST OP X-RAYS

CAD-Ray Distribution LLC has a training facility located in downtown Los Angeles that also operates as a full service dental practice.  We house and operate imaging machines for digital impression, we can take CT images on patients, and we can fabricate restorations in house.

We also have a close working relationship with Burbank Dental Lab which houses a variety of milling, printing, and fabricating machines.

Our programs are designated for CE credit by CAD-Ray Inc.