A computer-implemented method of designing a dental restoration at a display includes providing a virtual three dimensional representation of at least a portion of the patient's dental situation. The method includes displaying a virtual three dimensional dental restoration model in an alignment with the virtual three dimensional representation. The method also includes providing a design tool selectable to deform at least a portion of the three dimensional dental restoration model. The design tool, when selected, enables a line to be drawn on a surface of the three dimensional dental restoration model.