And yet, standing behind her son, waiting for the traffic light change, she remembered how in the midst of it all there had been a time when she'd felt a loneliness so deep that once, not so many years ago, having a cavity filled, the dentist's gentle turning of her chin with his soft fingers had felt to her like a tender kindness of almost excruciating depth, and she had swallowed with a groan of longing, tears springing to her eyes