Does anyone know what it means when the endodontist puts a piece of ice on a tooth in question, if you practically jump out of your seat from the cold does it mean that you need a root canal or does it mean that the nerve is alive and you do not need the root canal.
Thank you.

It means the nerve is alive

When I had to get my root canal I had an infection in the tooth that made it VERY painful and I had to go through the weekend before the dentist was open on Monday dealing with the pain. I found when I put something cold on it, it felt MUUUUCH better... so I was constantly sucking on ice cubes until I got the procedure done. I never had him test me with ice or anything... but I'm sure that would be an indicator of the nerve being alive hehe.

You will feel the cold in a healthy tooth, but the feeling should go away almost immediately after the source of cold is removed. If you experience extreme sensitivity to the cold and the feeling lasts for several seconds, the tooth probably has an inflammed nerve and most likely needs a root canal.