Not a direct answer to your question, but relevant.
A few years ago, my wife needed to have some dental work, and was referred to a dental surgeon for an extraction and root canal. I was allowed in the room to hold my wife's foot (the only spot I could be to not be in the way) to comfort her.
She didn't really "need" me to be there, but it helped ease the situation.
Not a direct answer to your question, but relevant.
A few years ago, my wife needed to have some dental work, and was referred to a dental surgeon for an extraction and root canal. I was allowed in the room to hold my wife's foot (the only spot I could be to not be in the way) to comfort her.
She didn't really "need" me to be there, but it helped ease the situation.
I think my kid will freak out if I am not with him.