Doctors always ask me for tips on cementation. One of the best tips I can give someone is to pack cord when you image and leave it in until you are done cementing.  I’m not a fan of just any cord personally. I used Ultrapak from Ultradent. I like it because it is knitted and compresses nice in the tissue and then expands it again after a few minutes. I usually use the largest cord I can pack into the sulcus that allows me to still see the margins 360 degrees. I find that I usually use the size 2 or 1 cord. I will pack the cord for imaging and then leave it in until the end of the procedure. 

This cord is very strong and does not seem to break into pieces like some cords do if you leave them in. I leave the cord in during cementation to prevent cement from going below the gingival contour.  

I let the cement get to gel phase and then clean it up. I will use a scaler interproximally to remove loose pieces and then light cure each surface for 10 seconds. Once the cement has been cured, I will remove the cord and use the scaler to remove any possible last remnants before dismissing the patient. When you take a pre op image, you will see how clean the interproximals tend to look.