Toothpaste demo test - particles hitting object that flakes away - newby challenge

I would like to play with the particle system and so I have chosen to recreate a toothpaste demo sequence i saw recently on TV. I am sure that you have all seen this sort of thing before.
A flow of toothpaste particles hit a wall of plaque. The plaque disintegrates into grey coloured particles, floating away whilst the teeth and gums become white and clean. At first I thought this would be a relatively simple task but …
For the moment, I am at the very beginning of my tests. I have a particle flow that follows a path and hits a plane. The particles react naturally, as if they were beads hitting a floor.
So my first question is, how should I be thinking about this test. I have chosen to do it with particles but I have no idea if this is a good choice as I need alot of control. Secondly, I am wondering about the impact. I see those that use cell fracture and physics to impacts and other that use the game engine. What would be best for this idea? (I don’t know how to use either yet)
Any ideas are very welcome
Many thanks