I've heard exercise and resistance/strength training increases the density, but doesn't increase mass. So basically, experimentally or theoretically possible at least, can modern science do this/is it feasible?
Density is just how "packed" the current bone is on the micro-level -- i.e., doesn't affect total mass potential. Filling or adding "density" is just like putting water in a fixed-size bucket until it fills. By "adding mass" I want the bone's bucket to be able to hold more density, i.e., a larger potential of density along with an overall greater weight to the bones themselves. I can't find any evidence that this is possible with long and flat bones alike, AKA the spine, leg and arm bones, clavicles and etc. -- or any bone.
I've heard facial bones are more malleable, but their bone mass cannot change with diet/training either.
So to make this as easy to understand as possible: Can bone mass in an adult be significantly changed somehow? Can I make my whole skeletal set heavier somehow, rather than just dense? Like for example, say I am considered "small framed." Rather than just density, could I make my frame bigger? Could I make my entire frame base more robust through some possible bio/drugs/etc. means?
And since I know someone will come along and claim this is a "medical/personal question," explain to me how this would be possible to ask in a non-medical/personal way then to enlighten me. Go ahead.