New, super-strong ceramic developed at Special Materials Center

April 6, 1995

ANN ARBOR—Heads up, hockey players and Lauren Hutton. The Specialized Materials Science Center at the University of Michigan has developed a less expensive crown with a new, super-strong ceramic core, called Magcor, that is ideal for capping front teeth.

” In general, crowns are constructed over two types of cores—metal and ceramic. The problem with the metal cores- through gum tissues like a purple stain—a real problem with crowns, or ‘caps,’ made for front teeth,” says William J. O’Brien, professor of dentistry and director of the center. “Our Magcor ceramic crown solves that aesthetic defect. ”

Better yet, the Magcor ceramic crown is four times stronger than crowns made from other ceramics. In clinical tests, only one out of 100 of the Magcor crowns broke and required replacement compared with 3 percent to 50 percent for other types of ceramic crowns.

Magcor, like all ceramics, is highly biocompatible. Metal crowns, on the other hand, especially crowns with nickel alloys, trigger allergic reactions in about 6 percent of women and 3 percent of men.

The U-M crown costs less to manufacture than other ceramic crowns, and half the amount of metal core crowns containing precious metals.

Magcor, which was developed by O’Brien, combines magnesia and glass in a glass ceramic and, with a flexure strength of 19,000 psi, it is twice as strong as traditional dental porcelain.

” We strengthened the Magcor crown more than twice again, to about 39,000 psi, when we coated the interior of the core with a ceramic surface coating similar tot he glaze used to protect ceramic pottery. The coating strengthens the interior surface and prevents cracks from spreading through the crown. ” O’Brien is the first to put the ceramic surface coating to use for dental purposes.

The U-M Specialized Materials Center is funded by the National Institutes of Health


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