Exit the Geometry Mode, go to the Modifiers List and add a Symmetry Modifier. Set the Mirror Axis to Z. Now expand the Symmetry Modifier and click on Mirror. With Snaps enabled, move the mirror so the two halves connect one to the other.
Switch to Polygon Subobject mode and select all the top polygons of the toothbrush' head. Bevel them using these settings: Bevel Type: Group; Height; 0.4; Outline Amount: 0. Hit OK, then delete all the polygons created on the Symmetry plane.
Select all the top Edges of the Head and Chamfer with 0.09 Chamfer Amount. Hit OK.
We have just opened our tutorial directory! Feel free to submit tutorials hosted on your website or other online tutorials that you think are worth mentioning.