How does Nelson DeMille use imagery in The Charm School?

Examples of Imagery:

"An old woman approached and smiled widely, giving Hollis the impression she was wearing someone else's dentures." Chap. 1, p. 85

"He didn't know what a behavioral psychologist would make of this maze and its white rats, but Hollis' theory was that the people inside the walls had somehow absorbed the malaise of the people outside the walls." Chap. 15, p. 195