On pages 74-75, what dramatic effect is increasing as a result of the commercial playing in background as Montag tries to memonize Bible?

Montag is attempting to memorize Matthew 6:28. He finds his concentration broken by the constant television ads -- even in a subway -- for toothpaste: "Denham's Dentrifice." The silly jingle is juxtaposed with Montag trying to read something with great wisdom and substance.