Toothache.

The American Dental Association is preparing to go to trial in a defamation case against a Van Nuys lawyer who has sued the trade organization for allegedly exposing patients to high levels of mercury in fillings made of amalgam, which is an alloy of mercury and silver.

Shawn Khorrami, who has his own law office, had sued the ADA and other dental groups for allegedly endangering the public by encouraging its members to use mercury fillings, statements made by Khorrami on his Web site and in press releases are false and defamatory, according to the ADA, which filed a federal lawsuit against the attorney in 2002.

Court documents filed by the ADA maintain that Khorrami falsely said the association had made efforts "to conceal the dangers associated with amalgam for the financial benefit of itself and those of organized dentistry" and had "exercised undue and unfair pressure on dentists not to warn their patients of the dangers of mercury." In addition, the suit said, Khorrami concluded that "amalgam fillings represent nothing more than a con on the U.S. population, orchestrated by the American Dental Association and its web of constituent associations."

Both parties are expected to meet for mandatory settlement discussions later this month. A trial, originally scheduled this month, was recently re-scheduled for April.

"The defamation case is based entirely upon statements made on his Web site about the ADA in which he was advertising for potential clients," said Melvin Avanzado, a partner at Jeffer Mangels Butler & Marmaro LLP who represents the ADA.

Khorrami, whose Web site no longer includes the alleged statements but makes brief reference to the ADA's "illegal business practices in concealing the risks associated with such fillings," did not return calls.

Staff reporter Amanda Bronstad can be reached at [phone], ext. 225, or at [e-mail].