Ann Arbor, MI — December 13, 2011 — Two residents in the University of Michigan School of Dentistry’s graduate prosthodontics program won a first place award for their poster presentation during the American College of Prosthodontics recent annual meeting.

Drs. Dimitrios Chronaios and Lisa Kane, both third-year residents, won the top award for their work that focuses on ways that may be more economical to fabricate porcelain fused to metal crowns using a cobalt-chrome alloy and a CAD/CAM milling process.  The implications of their research could ultimately affect the cost to dental patients and practitioners.

In recent years, the price of gold alloys that are used to make dental crowns has risen as the cost of gold has increased.  To help mitigate the effects of rising commodity costs, dental practitioners have been looking at possible options, including using other alloys.  However, in some instances, there are problems, both in terms of biocompatibility and ease of casting. 

Cobalt-chrome alloys have a long history and clinical track record, according to Dr. Michael Razzoog, director of the School’s graduate prosthodontics program.  However, these particular alloys are difficult to cast and contain nickel, a metal many patients are sensitive to.  “To cast a cobalt-chrome alloy, trace elements are included which have been known to cause a reaction in some patients,” Razzoog said.  He added, though, that a milled cobalt-chrome alloy does not need to have these elements included, and that CAD/CAM milled alloys do not contain nickel or other metals for strength or function. 

Chronaios and Kane have proven that these new alloys, when milled, have the same accuracy as traditional crowns and may provide dentists and their patients with an option to consider other than gold.  Their poster, “Marginal Adaptation and Internal Fit of Recently Introduced CAD/CAM Copings, was mentored by Dr. Furat George, a clinical assistant professor who co-directs the D3 predoctoral implant treatment planning course and a member of the American College of Prosthodontists.  Chronaios’ and Kane’s research was partially funded by the Delta Dental Fund.