How to fill big holes that Meshmixer couldn't inspect?

Question

How to fill these holes in mandibular jaw in order to 3d print it?

Answer 1

I have not used meshmixer, but both blender and meshlab have features to repair non-manifold meshes, including a way to manually fix large holes.

With both of these packages, you can have it select holes, and then either attempt to fill them automatically (which frequently gives terrible results), or manually select a few edges of a specific hole and add a few triangles at a time until it is fully covered (which gives much better results if you choose edges carefully).