The invention relates to a process of retraction of sulcus, comprising the steps of: applying a silicone material onto and/or at the vicinity of the boundary of a tooth and adjacent sulcus, which silicone material expands during or after its curing reaction; applying a cap onto said tooth, thereby forming a chamber over said silicone material, wherein said chamber comprises as its walls the tooth, the cap and an outer section of said sulcus; whereby said chamber allows for the silicone material to expand into the crevice between sulcus and tooth. Said cap is at least partially filled with a plastically deformable material when applied onto said tooth in step; and/or said cap is deformable, especially under biting pressure.