A routine dental visit for a San Diego third-grader ended in heartbreak on March 18, 2025. Nine-year-old Silvanna Moreno went into Dreamtime Dentistry in Vista for a three-hour procedure under general anesthesia. Hours later, she was pronounced dead at Rady Children’s Hospital.
Silvanna, described by family as a vibrant girl, had dealt with tooth pain since late 2024. Due to her age and anxiety, she was referred for treatment with sedation. The office used a combination of anesthetics, including nitrous oxide (laughing gas), propofol, sevoflurane, and others such as midazolam.
After the treatment, she was transferred to the recovery room. It was stated by the dental office that she had been discharged in a stable state, awake with stable vital signs and intact protective reflexes. During the drive home, she fell asleep. At home, she became unresponsive. Her family called 911. Despite efforts at the hospital, including CPR and epinephrine, she died shortly before 6 p.m.
The cause of death according to San Diego County Medical Examiner’s Office was accidental. The cause was methemoglobinemia in the setting of recent nitrous oxide administration. Contributing factors included other anesthetic medications.
Simply stated, it is a very rare blood condition in which hemoglobin, a protein that transports oxygen, becomes changed and thus cannot transport oxygen efficiently. It can cause symptoms like bluish skin, fatigue, and slowed breathing. Doctors note it is extremely uncommon but can be triggered by certain drugs, including nitrous oxide in susceptible people.
Silvanna’s mother, Itzel De Jesus, filed a malpractice lawsuit in late December 2025 against Dreamtime Dentistry, Dr. Ryan Watkins, Dr. Kyung Lee Boen, and others. The suit alleges negligence in monitoring, anesthesia administration, and post-procedure care, claiming an inappropriate discharge allowed the condition to go untreated.
The dental practice responded that they followed standard protocols.
“She was discharged in stable condition awake, with stable vital signs and protective reflexes intact,”
Dr. Ryan Watkins stated. The office added that no warning signs appeared during treatment or recovery and described it as a rare, undiagnosed reaction.
“This was not due to dosage but instead due to her rare but undiagnosed/undetected medical condition.”
Back then, Dr. Watkins already faced penalties. A few years earlier specifically in 2016 a man aged 54 went into heart failure while under sedation; because of that incident, the state dental panel put Watkins on probation, a status that lasted until roughly 2023.
Most kids come through dental anesthesia without issue, provided things go smoothly. Still, incidents happen prompting closer looks at how patients are watched during office procedures. Families might leave unsure what to watch for once home. Rare problems do occur, even if chances stay slim.
This loss leaves a family grieving and prompts broader discussion about patient safety in pediatric dentistry. As the lawsuit proceeds, it highlights the balance between necessary procedures and rare medical risks. Our thoughts remain with Silvanna’s loved ones.
