Intaglio: The lines of the image are incised, or cut, into a metal plate. This can be done with sharp tools, as in engraving, or with acid, as in etching and aquatint. Ink is applied and forced into the incised areas. Ink remaining on the surface is removed, and the plate is ready for printing.
Brushing alone won't remove plaque and tartar like this. A professional cleaning by a Veterinarian is the only way to restore your pets teeth to this healthy a shine. (I would've also removed the gingival hyperplasia between the upper incisors, but that's up to your Vet)