A 5-year-old Chicago girl who was sedated during a visit to the dentist never woke up and remained in a coma late last night at Children's Memorial Hospital.

Hospital officials say Diamond Brownridge, who had just started kindergarten, was on life support and in critical condition.

The girl's mother said her daughter was given an oral sedative, followed by an intravenous sedative and nitrous oxide gas at a storefront dental clinic in Chicago's Little Village neighborhood.

Diamond had complained of tooth pain and had been diagnosed with two cavities. In addition she was going to get caps on her lower front teeth.

The mother said she was told to leave the room during treatment, and when she returned a half-hour later, after paying the bill, she found her daughter lying on her side in the chair, not breathing.