The dentist cranks up his drill, revs it up and digs in. At first, no problem. The Novocain kicked in minutes ago. Half our head is numb. He asks us a question and we nod spastically. He asks another and we mumble like Steve Martin in “The Jerk” when reading Bernadette Peters’ goodbye note that fell in the bathtub. Meanwhile his drill keeps buzzing. The buzz gets louder, harsher. Our jaw—and finally our whole head—start vibrating. The sadist in the face mask and rubber gloves drills deeper, deeper. Soon—“AAWH!” We wail in pain. He went too deep. Either that, or...