Fraifeld said part of the anesthesiologists' job is not just to administer the right amount of medicine to leave people unconscious and pain-free, but to also constantly monitor numerous vital signs during the operation.
"We don't just monitor breathing but the depth of the respiration, heart rate, responses to stimulation -- are they holding still or are they moving around -- blood loss, urinary output, monitoring medications," Fraifeld said. "There's a whole lot that you're looking and you're doing it all at once."
Without hearing more about Hill's case, Fraifeld said it would be impossible to tell what could have caused the tragedy.
"Worst case scenario is almost anything can go wrong," Fraifeld said. Previous deaths have been caused by an allergic reaction to medicine, an undiagnosed heart condition, or when patients vomit during the procedure and choke, he said.
Counting deaths from anesthesia may be difficult because of litigation, but a study published in the journal Anesthesia and Analgesia counted very few child deaths from cardiac arrest. The study, which collected anonymous reports from 80 medical institutions in the United States, counted a total of 193 pediatric cardiac arrests due to anesthesia between 1998 and 2004.
Dentists say they always have to consider the odds when treating a child who has an infection that could threaten their ability to eat properly.
"Our typical resident graduates with over 400 sedations -- so a lot of kids need to be sedated, this is not uncommon," said Dr. Kevin Donly, chairman of pediatric dentistry at the University of Texas Health Science Center in San Antonio.
Donly said the cavity rates for children age 2 to 5 has increased for the first time since dentists have been keeping track. If these children aren't treated by age 5, Donly said it's possible they may need crowns.
And with a wriggling, crying or even completely uncooperative child, sometimes dentists turn to sedating children.
"When you're a 6-year-old, it's hard to sit through a procedure in the dentist chair," Donly said. "Some kids are more afraid of needles than others and you have to sedate them."
Donly said infection is a real threat with very deep cavities that would require a crown after a filling to stabilize the tooth. If the infection goes on, the child may have serious problems eating and be in a lot of pain.
"We always sit with every parent and patient -- we go through all the risks and we give them informed consent," Donly said. "It's no different than if your kid had chronic earaches and you have to have them put under general anesthesia to put tubes in.
"You play the odds, and ask for yourself if this is the right thing to do for my child," he said.
But dentists say sedation will probably always have to be a risk-benefit analysis.
"There's always a risk of some unknown condition that no one knows about and then under the stress of surgery or anesthesia that condition raises its head," said Dr. Joel Weaver of the American Dental Society of Anesthesiology.
"Again, the dentist has to weigh the risk versus benefits," he said. Weaver mentioned that overdoses during dental sedations are "far less than 1 percent."
The Associated Press contributed to this report