Style is in the smile.

Grunge music devotees go for frayed jeans and flannel. Heavy metal aficionados prefer leather and studs. For the well-appointed rap fan, the latest is worn not off the shoulder, but on the teeth.They're called fangs, rap caps or fronts. And the removable gold teeth covers - often studded with diamonds or stamped with designs - are glittering on the incisors and bicuspids of image-conscious teenagers.

"It's the new style coming in," said Rob Hendricks, 19, who cracked his lips to reveal a set of the caps encasing six of his upper teeth.

"It's a thing now. They're real nice," said Hendricks, standing in a Brooklyn mall where costume jewelry shops prominently displayed hundreds of the decorative dental caps.

While such caps have been around for years, their popularity has been boosted by rappers like the Wu-Tang Klan, who wear the ornate caps.

The caps, created by jewelers based on an impression of the customer's teeth, can run from a $40 simple gold cover to a gem-studded, intricate bridge costing $600 or more.

Ultimately, the caps could end up costing more - in dental bills.

Dr. Richard Price, a clinical instructor at the Boston University Dental School and a consumer adviser to the American Dental Association, said that with continued use, the bridges can crack teeth and cause cavities and gum problems.

"I don't know how much skill goes into these," Price said. "I sure wouldn't go long term with it."

One mother believes the caps cost her son his life.

Adonis Matthews of Brooklyn was wearing a $550 gold-and-diamond fang set, along with other jewelry, when he was killed in a robbery Tuesday.

The 17-year-old told police before he died that he was shot after refusing to turn over a gold chain and medallion to thieves on a subway platform. But his mother, Wanda, who gave the expensive cap set to her son for Christmas, was convinced it triggered the robbery, police said.