SAN DIEGO, Calif. (KGTV) — The death of a nine-year-old girl who passed away hours after being given anesthesia during a dental appointment has been ruled an accident by the San Diego County Medical Examiner's Office.
Silvanna Moreno died in March after visiting Dreamtime Dentistry in Vista.
The autopsy report on the child released Thursday said Moreno died from a rare blood disorder after being given laughing gas along with a cocktail of drugs, including propofol and hydromorphone.
“This 9-year-old … died as a result of methemoglobinemia in the setting of recent nitrous oxide [laughing gas] administration. Administration of dexamethasone, glycopyrrolate, hydromorphone, isoflurane, ketorolac, midazolam, ondansetron, propofol, and sevoflurane was a significant contributing condition,” the autopsy obtained by ABC 10News says.
Moreno had a fever the morning before her appointment, which lasted about three hours, according to the report.
"On the morning of the dental procedure (03/18/2025), the decedent complained of a headache without appearing distressed," the autopsy says.
The autopsy report said she was getting a root canal, crowns, fillings and teeth pulled.
The child was “out of it” after surgery and mumbling her words, according to the medical examiner.
She was able to stand but fell asleep on the drive home and later that afternoon became unresponsive.
Dreamtime Dentistry dentist Dr. Ryan Watkins said in a March statement that his office was “deeply saddened by the tragic passing of our young patient, which occurred several hours after her completed dental procedure.”
The dentist said the girl was referred to his office for treatment under anesthesia due to her young age and anxiety.
“Our hearts break for the family during this unimaginable time of grief, and we extend our deepest condolences as we maintain our focus on supporting the family and cooperating fully with the medical investigation.”
Dental office says it followed protocols
In a statement sent by a public relations company after this story was published, Watkins' office said it wasn't aware Moreno had been ill before her appointment.
"Our records show that the patient's mother completed and signed a pre-operative check-in form indicating 'NO' when asked if the patient was sick."
Dr. Watkins follows standard protocol, and if he had been aware of any recent fever or illness, the clinic would have rescheduled the child's appointment, the statement said.
"Dr. Watkins conducted a thorough review of the patient's medical and dental history and completed a pre-operative examination. No pre-existing conditions were disclosed or documented in the available medical records."
Dreamtime Dentistry said the medications it used are standard anesthesia drugs commonly used in pediatric dental sedation procedures.
"The dosage administered was appropriate for the patient's age and weight, following established medical protocols," the clinic said.
The report from the medical examiner said San Diego police requested to attend the autopsy.
It said only laughing gas has a known connection to methemoglobinemia, but acknowledged the other drugs Moreno received could also have been a factor.
The report said methemoglobinemia can be hereditary and recommended genetic testing of relatives.
