The present invention relates to a kit of parts comprising Paste (A), Paste (B) and Paste (C), the pastes being characterized as follows: Paste (A) comprising at least one polyorganosiloxane with at least two olefinically unsaturated groups, and at least one organohydrogenpolysiloxane, at least one alkylsiloxane having at least one carbinol, silanol, alkoxy, carboxyl or amino group, optionally filler(s) and optionally additive(s); Paste (B) comprising at least one polyorganosiloxane optionally with olefinically unsaturated groups, at least one addition cure catalyst, optionally at least one alkylsiloxane having at least one carbinol, silanol, alkoxy, carboxyl or amino group, optionally filler(s) and optionally additive(s) Paste (C) comprising a softener, a condensation cure catalyst, optionally filler(s), and optionally additive(s) optionally at least one polyorganosiloxane optionally with olefinically unsaturated groups. The invention is also directed to a system for storing and delivering Paste (A), Paste (B) and Paste (C), the system comprising three compartments for storing the respective pastes, means for delivering the respective pastes to an outlet orifice and an interface for receiving a mixing tip. The kit of parts or the system is in particular useful for conducting a dental retraction and dental impression process.