A tool for forming a hump along a substantially flat surface of a dental matrix, Said tool having first and second forming surfaces for urged together to form said hump on said matrix inserted therebetween, said forming surface having one portion part-spherical and another transverse convex arch-shaped project and a flat forming surface extending around of said project, and said second forming surface having one portion part-circular and another transverse concave arch-shaped cavity opposite said project.
