what the CEJ?

My patient that came in today is so funny and he has a great sense of humor and he keeps me laughing the entire time. He was a class III and he had a lot of recession. I am having problems getting the feel for the difference between calculus and the CEJ and root surface. I am nervous about removing cementum by being to aggressive. Even after my scale check I still felt like there were areas where the tooth felt rough, but it wouldn't come off! This was a great learning experience for me for trying to feel the difference between different structures. Another issue was that his gums were tight instead of "flappy" so it was harder to get under them with bulky instruments. I just need to get over my fear and get them down there. I only finished 2 quadrants on him, and I wish I could have completed him today, but I just didn't have the feel for it. I get scared that I went over it too fast and that I am going to have errors.