Colfax dentist installs high-tech tools

Rob Smith

Gazette Staff

Colfax dentist Dr. Robert T. Smith uses computer-driven manufacturing every day in his practice and explained the high tech tools and how he applies them.

The use of machines controlled by computer programs to create physical parts has been around for decades.

In the 1980s, for a computer-driven machine to create a part, it first had to be defined digitally, drawn up by a human in a computer program such as AutoCAD. Next, that drawing would be used as a reference by a programmer to manually write a computer program to guide a machine tool step-by-step in how to create the part. The process was slow, laborious and expensive, but if thousands of copies of the same part were needed, the economies of scale brought the cost down to an acceptable level.

A tooth, however, lies on the opposite end of the spectrum, in that it is a unique part of which only one copy is needed.

The challenge, then, is how to model the tooth shape and create a machine tool cutting path quickly and accurately.

It took the advent of a technology known as Cerec optical scanning to make this viable and practical enough for use in dentistry. To map a tooth, a hand held scanner is moved over and around the tooth, then software stitches the digital snapshots together to create a complete three dimensional model of it. The resulting highly accurate map of the complex tooth shape can then be used to fabricate a crown.

Next, the doctor employs his knowledge to fine tune the model and makes any necessary adjustments, then feeds it through software that creates a cutting path for a two-axis milling machine. This machine carves the tooth shape from a solid block of unfired porcelain, cutting both the underside and outside surfaces, all within a few minutes and within the dentist’s office. After a test fit is approved, glazing and firing harden the crown, making it ready for permanent installation, again, with all steps performed in-house. For the patient, a crown can now be done in one appointment. No more two week wait for the lab to create the part while wearing a temporary.

For more involved procedures such as replacement of a tooth with an implant supported crown, the same tools can be used in conjunction with a 3D cone beam scan to create a surgical guide stent, a temporary guide fixture that enables very precise placement of an implant.

By merging the optical scanning of Cerec with the 3D cone beam scan, a detailed and accurate virtual treatment plan can be developed, before any work on the patient begins.

“The fit of the crowns has been incredible, and implant placement has been much more predictable,” noted Dr. Smith.

For Dr. Smith and his staff, who regularly attend training to keep up to date in their field, this latest advance is another step in progressively improving patient care.