Animation with deformation.

Hello to all,

I’m a new to graphics design need to build some animation for medical purposes. I need to show a human tooth. Some elastic stick should be able to slide inside the tooth and outside, in a curved tunnel which is inside the tooth. The the tooth should look transperent, so it will be clear on which position, the elastic stick is currently in, and what is the shape of the tunnel.
Here is a video of something similar, so it will be more clear what I have described:

  1. The stick’s thickness is equal all over it’s body and is thicker then tunnels thickness.
  2. The stick is moving inside and outside the tunnel which is curved and slimmer then the stick.
  3. Because the stick is “self adjusting”, it’s portion, which is currently inside the tunnel is self adjusting to tunnels shape.

Until now, I have followed following tutorial (1-7) from this website:
So I have a basic understanding of modelling and animation.

I know how to move a mesh a long a curve. And I know that this is some kind of deformation but it only applies to the part of the mesh which is inside the tunnel.

So, please tell me which technique can achieve this self adjusting animation.

Thanks in advance.

Curve modifier
Lattice modifier