@thisiscian You probably want to drybush with a white colour. Take one of your brushes that you're happy to ruin, get some paint on it (deep into the brushes), wipe almost all of it off and then give it a pass over the teeth.

In your images, it doesn't look like the resin (?) has a huge amount of definition to the teeth edges, so it might not work terribly well (in which case, you'll have to do traditional highlighting with brushwork)

@olistiel I drybrushed other parts, with varying success, felt like the teeth were too small for the brush I had