What was intended to be a standard dental appointment turned tragic for 9-year-old Silvanna Moreno, who passed away on March 18, 2025, merely hours after receiving a dental procedure at Dreamtime Dentistry in Vista, California.
More than two months later, the San Diego County Medical Examiner determined her death to be an accident, attributed to “methemoglobinemia in the context of recent nitrous oxide administration.” This uncommon condition disrupts hemoglobin’s capacity to transport oxygen, resulting in potentially lethal hypoxia.
Silvanna had been administered children’s Tylenol the day prior to the three-hour dental procedure. During the appointment, she underwent a root canal and multiple tooth extractions, including one permanent decayed tooth.
Dreamtime Dentistry indicated that Silvanna was a new patient referred for treatment. Dr. Ryan Watkins, the anesthesiologist at the office, stated that she had a history of regular medical examinations and was deemed a suitable candidate for outpatient general anesthesia.
Following the procedure, Silvanna was transferred to a recovery room. Her mother informed investigators that she appeared to be “out of it,” intermittently opening her eyes and mumbling. During the journey home and upon arrival, she remained asleep.
Approximately 30 minutes later, her breathing began to slow. When her family was unable to rouse her, they dialed 911. Silvanna was swiftly taken to the hospital, where she was declared dead.
“We are deeply saddened by the tragic loss of Silvanna Moreno, and our thoughts remain with her family,” stated Dr. Watkins in a press release.
Her passing underscores the uncommon yet significant risks linked to sedation in pediatric dental procedures.
