9-year-old girl dies after dental procedure in California

A 9-year-old girl from San Diego tragically died just hours after a routine dental procedure, sparking serious questions about anesthesia risks and medical oversight.

Silvanna Moreno had been dealing with painful dental problems since late 2024. On March 18, she visited Dreamtime Dentistry in Vista, California, for a lengthy dental procedure meant to ease her discomfort. The appointment included a root canal, crown placement, and the removal of several decayed teeth—both baby and permanent.

What no one expected was that just hours later, Silvanna would pass away in her sleep.

Her mother, Itzel de Jesús, had taken her to the appointment after months of toothaches. According to People and The Los Angeles Times, the day before the procedure, Silvanna had a mild fever that was treated with Tylenol. However, the dental clinic said it wasn’t informed of any recent illness. The pre-surgery form signed by her mother reportedly indicated the child was not sick.

Dreamtime Dentistry said that had they known about the fever, they would have postponed the procedure.

Procedure completed without signs of trouble

Dr. Ryan Watkins, the clinic’s only dentist and anesthesiologist, performed the procedure and administered the anesthesia. The clinic told FOX 5 San Diego that Silvanna was “continuously monitored” and showed no concerning signs during or after the operation.

“She was discharged in stable condition – awake, with stable vital signs and protective reflexes intact,” the statement read.

After the procedure, Silvanna was able to stand and respond briefly. But once home, she appeared very drowsy and began snoring heavily in her sleep—a sign her family now believes was a warning.

After being carried inside her house, Silvanna slept for about 90 minutes. Her snoring slowly quieted, and her breathing began to slow. Alarmed by the change, her grandmother checked her heart rate twice. The second time, Silvanna was unresponsive.

Emergency services were called just before 5 p.m.—nearly six hours after her surgery. She was rushed to Rady Children’s Hospital, where doctors confirmed she was in asystole, also known as “flatlining.” Despite life-saving efforts, Silvanna died shortly after.

The San Diego Medical Examiner later determined that Silvanna died from methemoglobinemia—a rare blood disorder that can be triggered by certain medications or chemicals, including nitrous oxide, a common dental anesthetic.

This condition causes the blood to carry less oxygen, leading to tissue damage or death if not treated quickly. While methemoglobinemia can be inherited, it’s far more often caused by external triggers. According to NBC News and the Cleveland Clinic, this condition is extremely rare, with only a few documented cases worldwide.

The report noted that the combination of several anesthetic drugs used during her procedure likely played a role in Silvanna’s fatal reaction.

No warning signs, says clinic

Dr. Watkins insisted that Silvanna showed no symptoms of the condition during her time at the clinic.

“If we had observed any indication of methemoglobinemia, we would have immediately discontinued the procedure and transported her to the hospital,” he told NBC.

He also emphasized that the clinic followed all standard protocols and reviewed Silvanna’s medical history thoroughly. However, this isn’t the first time Watkins has come under scrutiny.

In 2016, Watkins was investigated by the California Dental Board after a 54-year-old patient nearly died under his care. Investigators found that he had used an inappropriate anesthetic drug. The patient survived but later sued. Watkins was placed on professional probation from 2020 to 2023 as a result.

Dreamtime Dentistry has said it is now conducting an internal review following Silvanna’s death, which has officially been ruled accidental.

Silvanna Moreno was one of four siblings.

Many parents are now wondering: how safe is dental sedation for children? Are clinics doing enough to screen for risks?

If your child has a dental procedure coming up, experts advise you to:

• Share any recent illnesses, even minor ones.
• Ask your dentist what kind of sedation or anesthesia will be used.
• Learn the warning signs of complications post-surgery, such as excessive drowsiness or unusual breathing.

What happened to Silvanna is a heartbreaking reminder that even routine procedures carry risks. Her story has sparked renewed calls for better safety measures, especially when treating children.

Do you think dental clinics should have stricter rules around pediatric anesthesia? Let us know your thoughts and share this story to raise awareness.