The little boy was born with a heart condition and had survived three open heart surgeries. His grandmother says she was told by a nurse that doctors administered gas as an anesthetic -- something he couldn't tolerate because of his condition.
Hospital administrators aren't saying which type of anesthetic the boy received, but they say his vital signs indicated he didn't receive too much.
The dental procedure was done at the hospital due to the risks posed by Harrison's heart condition. Family members doubt his ailment played a role in his death -- doctors say it is a possibility.
An autopsy will be performed to try and determine just how Harrison died.