Posted by: Fred

I'm still not sure what makes a mandible grow, except for testosterone exposure in the womb.

Apparently time. I have seen many old men with stronger mandible projection than teenagers. That being said, I think it depends on genetics. Some have large mandible genetics like myself. Others not so much. Hell in my cases my maxilla is so clockwise rotated that my formerly strong mandible appears weak. 

Can you show me what mandible you're describing? I have long ramus's due to nasal breathing.

This is something I notice in many women

I believe this specific photo comparison is of two different women, so it's not to say that this exact degeneration would happen to the young female skull example. As I understand it, the study mentions changes in eye sockets, nose, and loss of bone in the lower jaw, which all makes sense to me. But from this young female to the old female seems like it would be an intensely dramatic change.

Posted by: Sclera

I believe this specific photo comparison is of two different women, so it's not to say that this exact degeneration would happen to the young female skull example. As I understand it, the study mentions changes in eye sockets, nose, and loss of bone in the lower jaw, which all makes sense to me. But from this young female to the old female seems like it would be an intensely dramatic change.

But the lower jaw doesn't really lose mass. It just states being pulled down by gravity as the maxilla recedes. It then appears larger as the dentition becomes more Class 3 like. 

The mandible does not grow past the age of 12-14. It does not even remodel, except in the condyles and alveolar ridge. In one presentation Dr. Mike Mew showed bone remodeling in a monkey experiment and commented that the mandible did not change shape only the maxilla got shorter. It's very hard to induce change where there is no muscle to perform that role.