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Biomimetic Crown Transfer

A while back, a member of our study club came across a case report by Pascal Magne titled:

An approach to biomimetics: the natural CAD/CAM restoration: a clinical report.

The report basically involved tricking the digital system to mill a real molar into the shape of a crown restoration. The idea seemed pretty awesome, because what restoration material can be better than our own biological enamel?

The method does not seem particularly difficult, so that got me thinking:

Does our clinic use the same system (CEREC)? Check.

Do we have spare milling blocks lying around? Check.

Do we have too much free time? Double Check.

Is there practical clinical application? Who cares.

All aboard the train of discovery!


The Procedure

The donor tooth, which has been submerged in a hydrogen peroxide solution for an unknown period of time.

 

The donor tooth after trimming the root.

 

We opted for a crown preparation instead of an onlay. Unfortunately, this became problematic because the recipient site was wider near the margins than the donor tooth. This means that the margins on the final restoration would be smaller than our design.

 

A second stone cast with the treatment site trimmed and fitted with the donor tooth.

 

This configuration was scanned to create the reference BioCopy.

 

Biocopy (brown) with restoration design (white) overlay.

 

Last step of the restoration design process before milling.

 

Ensuring that our special block is large enough to accommodate the donor tooth. One of the plates would later be removed.

 

Silicone impression of the milled restoration.

 

The silicone impression was used as a positional guide for the donor tooth and the block handle.

 

With their positions determined, the donor tooth was bonded onto the special block with resin cement.

 

In this case, there is no such thing as too much cement.

 

Now, the moment of truth.

 

The finished product. Notice the chipping on the lingual margins, which was due to the aforementioned size difference between the donor tooth and the recipient site.

 

Finished biomimetic restoration: occlusal view.

 

Finished biomimetic restoration: lingual view.

 

Finished biomimetic restoration: pretentious psuedo-artistic view.

Conclusion

Although the current clinical application of this procedure is questionable, in this experiment we have shown that it is technically feasible. Now, the big question is whether enamel is, in fact, the better restorative solution to ceramics. If this is true, then there is no doubt in my mind that newer and revised iterations of this method will become viable in the future.