Leverdude, I know there is different grades of serving thread. I know some are very strong and hard to cut, I usually go to my pro shop and ask for a few feet of some good quality serving thread and the charge very little for it if any at all. I have used dental floss to serve in a peep before and it worked fine, I only used it one time. If dental floss was as good or better than serving thread there would be alot of pro shops using it, since floss is alot cheaper.