1.   His teeth flashed briefly and brilliantly.

2.   He grinned, white teeth flashing in his tanned face.

3.   His teeth flashed whitely as he glanced up from his task.

4.   His gold tooth flashes.

5.   Prominent teeth flash with intermittent bursts of laughter, and her country-girl face is framed by dense, reddish curls that she has refused to straighten.

6.   The teeth flashed in something between a smile and a bite.