Chicago ? A 5-year-old Chicago girl who never awoke from her sedation during a visit to the dentist died Wednesday at Children’s Memorial Hospital, a hospital official said.

Kindergartner Diamond Brownridge had been in a coma and on life support since the weekend dentist visit, said Julie Pesch, a spokeswoman for the hospital.

Family members have said Diamond received a triple dose of sedatives – an oral agent, an intravenous drug and nitrous oxide gas – during Saturday’s exam at Little Angel Dental. The girl was having two cavities filled and caps placed on her lower front teeth.

The girl’s mother, Ommettress Travis, has said she was asked to leave the room during the half-hour procedure. When she returned, her daughter was lying in the dental chair, not breathing, Travis said.

A Chicago law firm, Clifford Law Offices, also filed paperwork to begin exploring if a malpractice case would have merit, said Thomas K. Prindable, managing partner of the firm.