Daisy Lynn was a "happy, healthy baby" and "full of life" before the visit, her aunt says. But then Jessica Casaneda says the 14-month-old "went to the dentist and never came home."
Another family member told KXAN-TV the baby went to get cavities filled at the dentist's office.
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A spokesperson for Austin Children's Dentistry would not confirm the exact procedure, but did say it was a standard one.
It isn't clear yet why Daisy died.
"The child was a patient and did need to be transferred to additional medical attention yesterday morning," says Sarah Marshall with Austin Children's Dentistry.
The medical examiner's office says the child died about five hours later.
The spokesperson for the dental office says a dentist and anesthesiologist were in the room with the child.
The dental office is still waiting to hear more from the medical examiner, with an autopsy scheduled for today.
"Everybody's thoughts and feelings are concerned about the family at this point," Marshall says. "We don't have any additional information about what specifically has happened. We're waiting on those details."
The results of the autopsy have not yet been released.
The medical examiner's office says the cause of death is pending.