WEDNESDAY, Jan. 19 (HealthDay News) -- If you're considering tongue piercing as a form of self-expression, know that new research suggests that whether the stud used is metal or plastic makes a difference when it comes to chances of infection.

Stainless steel studs may collect more bacteria than plastic studs, potentially increasing the risk of infection and other complications, a team of European researchers reports.

"Consumers should avoid stainless steel and titanium studs in favor of [plastic], not only because of bacteria and a potentially higher risk of local infection of the piercing channel, but also because of the risk of tooth chipping and gum recession," study author Dr. Ines Kapferer, of Innsbruck Medical University in Austria, said in a statement.

Tooth chipping and receding gums, as well as gum disease, are some of the long-term complications associated with tongue piercing, prior research shows. Early complications include pain, swelling, prolonged bleeding and swallowing difficulties. What's more, the mouth contains so many bacteria that the piercing procedure itself may increase the risk of infection, one of the most common piercing complications.

One source of infection may be thin layers of bacteria, called biofilms, that coat piercings and act as a reservoir for germs, according to Kapferer and colleagues. They speculated that using piercing materials that were less susceptible to biofilm accumulation may reduce infection risk. To test their theory, the study authors recruited male and female students throughout Innsbruck whose tongues had been pierced for at least six months.

After conducting dental exams, the researchers randomly replaced the students' studs with one of four common piercing materials: stainless steel, titanium, or one of two types of plastic. The studs were removed after two weeks and microbiological samples were collected from the stud, the piercing site and the tongue.

A total of 80 different species of bacteria were collected from the various sites and the tongue harbored most of the bacteria, the researchers reported in the Jan. 18 online edition of the Journal of Adolescent Health.

Eighteen bacterial species were more abundant in the piercing site than on the tongue and six species were more prevalent on studs than the tongue. Eight other species were more plentiful on studs than in piercing sites.

Stainless steel studs were the biggest culprit, accounting for the highest bacteria counts, followed, to a much lesser degree, by titanium studs, the researchers reported. Bacteria found on these metals included those known to cause body-wide infections, such as Staphylococcus aureus and Haemophilus influenza. Both metals had significantly greater bacteria counts than did plastic studs.

Yet, this accumulation of bacteria may not be the biggest worry, said Dr. Valerie Murrah, of the University of North Carolina at Chapel Hill. "As an oral pathologist, I'm concerned with infections of the tongue," she said, noting the importance of sterile piercing techniques.

Among the 80 study participants, who ranged in age from 16 to 36 years, 23 (29 percent) also reported receding gums and four (5 percent) had at least one chipped tooth. On average, most had had their tongue piercing for five years.

"No matter what material [the stud] is made of, it's going to hit the back of the front teeth," said Dr. Ruchi Nijjar Sahota, a dentist in Fremont, Calif. "Most of the patients I've seen have developed either a gum infection or had some sort of trauma to their teeth because of the tongue ring," said Sahota, who is also a consumer advisor for the American Dental Association.

The American Dental Association currently opposes tongue piercing due to such potential complications, according to their online statement.

Sahota stopped short of warning against tongue piercing altogether, however. "I never want to be a killjoy," she said. "Just realize the risk of what you're doing."

"There are other ways to decorate that are less dangerous," added Murrah. "We only have two sets of teeth."

More information

For more information on tongue piercing, visit the American Dental Association.