Extrinsic tooth stain will be scored on the facial surfaces of the 8 incisor teeth using a modification of the Lobene tooth stain index (SI) (Lobene 1968). Each incisor will be scored for stain area on a scale of 0-3. The sum of the stain scores for the subject will be used as that subject's stain score. Scores will be recorded from 0 to 3 as follows: