+1 to getting a good matrix. It's the difference between a beautiful 5-minute temporary and an ugly 30-minute temporary.Easiest way, take the time to get a GREAT matrix to put the integrity into. It doesn't matter if you use an alginate, or PVS or even a prefabricated plastic suck down, the better the "template" you put the integrity into the easier and cleaner the margins you'll have to work on(And integrity is all that I've used as a temporary material for the last 6 or 7 years so I'm pretty familiar with it's properties)
Also, if you're having problems "reading" your margins in the integrity with respect where to trim/finish to, then really take a look at your prep before trimming, so you mentally know EXACTLY what that finish line looks like before you start trimming. This is where having a consistant, smooth finish line 360 degrees around the tooth makes a HUGE difference. Practice, practice, practice, you'll get it.
BTW, if you need to add to the margins, a little bonding agent and some flowable composite is all that I use and it works very well.
I use plastic suck down matrix, fill in the matrix and place it on the tooth and after 2 min, I remove the matrix (provisional remains on the tooth) and start carving the embrasures with a proximal carver, but it never seems to work! 80% of the time the prov. gets locked up and I end up breaking it while removing it.
In the clinic, I've seen people take off the matrix and the provisional together and I just don't know how they do it! Mine always stays on!!! Any tips?
I'm using natural teeth and margin seperator as lubricant.