Graftobian Tooth Wax is the “go to” product for the classic knocked out tooth or broken teeth look, or to simulate decaying and rotted teeth.
Use the brown colored Tooth Wax for the rotted and decaying teeth look. Depending on how you place the brown wax, and how much you use, determines the degree of the decayed rotted look.
The best way to start is to apply the wax fully to the dry teeth you want to distress, and then design the look by scraping partially off for a good rotted and decayed look. Ask the subject to moisten their teeth with their tongue.