The article describes a new technique for fabricating a wedge directly in the mouth during clinical procedures. It is called a passive wedge because it is kind to the soft tissues, exerting neither compression nor traction on them. A conventional rigid wedge may hurt the interdental papilla, initiating bleeding and the flow of fluids through the rubber dam. This new technique is very useful during adhesive procedures, because the wedge prevents moisture from invading the working area and the cavity, maintains the matrix in place, and causes no harm to the soft tissues, allowing the restoration to be finished properly.