More than two months after a 9-year-old San Diego girl died following a dental procedure, officials have released new details on her death.
The San Diego County Medical Examiner’s Office ruled the death of Silvanna Moreno an accident, according to an updated summary report. The girl died after she underwent anesthesia.
The medical examiner listed her cause of death as “methemoglobinemia in the setting of recent nitrous oxide administration.” Contributing conditions included the administration of multiple anesthetic medications.
Methemoglobinemia is a very rare blood disorder that affects how red blood cells deliver oxygen, according to the Cleveland Clinic. Not everyone experiences symptoms, but nearly all people with the disorder have skin, lips or nails that are blue or purple. In some cases, it can be life-threatening.
People can inherit the disorder, but it usually happens “when people use certain medications or recreational drugs or exposure to certain chemicals,” according to the Cleveland Clinic.
The dental procedure took place on March 18 at Dreamtime Dentistry in Vista.
Dr. Ryan Watkins, the office’s trained anesthesiologist, said methemoglobinemia can occur with the administration of nitrous oxide, commonly known as laughing gas. He said Silvanna never exhibited signs that something was wrong during the procedure.
“If we had observed any indication of methemoglobinemia, we would have immediately discontinued the procedure and transported her to the hospital for emergency treatment,” he said in a statement.
The day before the procedure, Silvanna had a fever and was given children’s Tylenol, People magazine reported, citing an autopsy report. The day of, she complained of a headache but did not appear to be distressed, it said. The dental procedure was three hours long, People reported.
The dentist’s office said Silvanna was a new patient and had been referred to them for a root canal on a molar. Doctors completed the root canal and restored the tooth with a crown. Some decayed “baby teeth” were extracted, as well as some decayed permanent teeth. One permanent tooth needed a crown, the office said, noting that three hours is normal for these procedures.
Watkins said Silvanna was “a healthy 9-year-old with a history of regular medical checkups” and underwent the office’s standard preoperative evaluation. He said he evaluated her as “an appropriate candidate for outpatient general anesthesia” and continuously monitored Silvanna throughout the procedure.
Afterward, she was monitored in a recovery area “until she was awake with stable vital signs,” he said. She was evaluated before she was released into her mother’s care, he said.
Silvanna’s family could not be reached for comment on Friday.
According to the medical examiner’s summary report, Silvanna fell asleep during the car ride home and stayed sleeping upon her arrival. Family members put her in bed and checked on her throughout the day.
Her family later found her unresponsive and called 911, according to the summary report. She was rushed to the hospital, where she was pronounced dead.
Watkins said the office is conducting an internal review of the case and will consult with experts “to ensure we continue to provide the safest possible care for our patients.”
“We are profoundly saddened by the tragic loss of Silvanna Moreno, and our hearts continue to go out to her family during this incredibly difficult time,” he said.
Watkins was previously investigated by the Dental Board of California after a 54-year-old patient nearly died in 2016, according to NBC San Diego. State investigators said the man was put under anesthesia and was given two drugs, which led to his heart stopping. Investigators had said that one of the drugs should never have been given to the man.
Watkins was put on probation from 2020 to 2023, according to a decision order. The man ended up filing a lawsuit against Watkins, which was later settled, NBC San Diego reported.
