The stock of Premier Laser Systems Inc., the Irvine developer of highly touted dental lasers approved for work on cavities, resumed trading on the Nasdaq market. The stock closed at $3.13, off $1.06 a share from its closing price May 22, the last session before trading was halted. But Colette Cozean, the company’s chairwoman, said she considered the performance heartening. “Most people thought it would stay in the $2 range, but it traded in the range of $3 and $4 nearly all day,” she said. Last week, a company laser received Food and Drug Administration approval for treating children’s cavities, but the impact on the stock appeared to be modest Thursday, unlike the huge surge last year when the same laser was approved for use on adult teeth. The spate of negative news about the company earlier this year has made investors wary, said John Doss Jr., analyst with Dominick & Dominick in New York. Premier’s stock slumped earlier this year after the company became involved in a dispute with a key distributor, had to restate two years of earnings and was hit with the resignation of its outside auditor. Doss said the company must prove it can persuade dentists to switch to the laser, which at about $39,000 is much more expensive than the traditional drill. Cozean said the device’s reception at an American Dental Assn. meeting in San Francisco this weekend is a key to its future.