Poor Impressions Means Poor Fit of

Q: My new dentist said my old dental work is failing due to poor fit. When I asked him why it was made that way, he said there could have been defects in the dentist’s impressions or lab work. Is this true, and how can I prevent this?

A For decades the inaccuracy of goopy, gagging clay-like impressions has led to poor fit of dental work resulting in failure of the work and even tooth loss. (This means ALL types of dental work: Implants, crowns, veneers, inlays, etc.)Although dental work at its best is not guaranteed to last your entire lifetime, you can appreciate the financial benefit of dental work lasting for many years vs. just a few years or months.

Bad impressions leading to bad dental work means you may have fracture and decay form underneath resulting in the need to extract the teeth. Poor fit can also allow implants to fail and fracture.

Back in 2008, were one of the first offices in Florida that invested in digital scanners that take 3D images of your teeth, allowing robots and/or 3D printers to mill virtual models of your mouth via CAD-CAM. We are now using the third generation of these scanners, called iTero Element.

In a past issue of the JADA (Journal of the American Dental Association) an article was published by three doctors on the accuracy of digital impressions, representing the US Navy Dental Corp, The University of Iceland, University of Florida and the University of North Carolina, Chapel Hill. (Imagine the fascinating conversation at that Christmas Party!)

Here are some take-home points from the study:

• 86% of (traditional, goop) impressions sent to the lab had AT LEAST one detectable error.
• 55% of these errors were CRITICAL errors pertaining to the finish line. (This is the area where if there is too much of a gap, decay can form allowing for future failure.)

Most of the problems are related to the inaccuracies of the impression material and the plastic or metal trays that holds the goop against your teeth. Tears, bubbles, saliva and blood adherence, material displacement and voids; none of these problems exist with digitally scanned impressions.