The coroner's office identified the toddler as Daleyza Avila Hernandez.
Her mother said a dentist referred her to Children's Dental Surgery in Stockton.
"I don't want this to happen to another mother like it's happening to me," said Araceli Avila.
Avila said she took her daughter in for the dental surgery and 30 minutes later, she said, they brought her back dead.
The administrator of the dental center said they only do general dental procedures, and they don't know why she died.