Story highlights Kids were infected with Mycobacterium abscessus from water used in pulpectomies

The dental clinic is cooperating with a joint state-county investigation

Anaheim, California (CNN) An outbreak that sent 30 children to Southern California hospitals and could have long-term effects on their health, is raising awareness about the risk of bacterial infection from water at the dentist's office.

All of the children had a pulpotomy, essentially a "child root canal" and were infected by water used during the procedure, said Dr. Matthew Zahn of the Orange County Health Care Agency.

The cases have been traced to the Children's Dental Group in Anaheim, with patients ages 3 to 9 years old all visiting the clinic between March and July.

"Several hundred people had these pulpotomies, so we are anticipating that for at least the next several weeks or months, we're going to see more cases," Zahn said. He added that the infection, called Mycobacterium abscessus, is slow-moving and can take weeks or months to show symptoms.

Swelling, redness and pain around the infected tooth can occur, with the bacteria often spreading to the gum and jawbone. In those cases, Zahn said, stopping the infection often means removing part of the jaw itself, making it "a long-term issue for these children."

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