J.S.
I have known kids to lose a tooth root and all, doesn't happen often and I would imagine I would freak a bit if it happened to one of my kids.
I don't think it has anything to do with being spectrum. My son lost all his teeth in the usual manner.
I also want to add no one can pull a tooth out with just their hands unless that tooth is already loose. I would be more concerned as to whether there is a bacterial infection attacking the teeth. Not being the best tooth brushers, that seems common with spectrum.