Class V Cavity Preparation
Placement of 212 Clamp
The facial beak is placed 1.0 mm gingival to the anticipated gingival margin of the finished cavity preparation. 
Compound must be neatly positioned over and under the clamp bows and secured into the interproximal spaces between adjacent teeth.  Remove any compound from the facial portion of the clamp to maximize easy and open operator access to the cavity preparation.
Class V, page 1