PURPOSE: To compare, with a double-blind, randomized, parallel-design clinical study, the hypersensitivity efficacy of a new Pro-Argin formula dentifrice containing 8.0% arginine, a high cleaning calcium carbonate system and 1450 ppm fluoride to a previously validated Pro-Argin formula dentifrice containing 8.0% arginine, calcium carbonate and 1450 ppm fluoride, and to a control toothpaste containing calcium carbonate and 1450 ppm fluoride, instantly after a single direct topical self-application using a fingertip, and after subsequent brushing for 3 days. METHODS: Qualifying subjects from the Chengdu, China area who presented two hypersensitive teeth with a tactile score of 10 to 50 grams, and an air blast score of 2 or 3, participated in this study. The first phase of the study consisted of a single topical application of the assigned product directly onto the hypersensitive surface of each of the two hypersensitive teeth. Study subjects applied a pea-size amount of their toothpaste onto the hypersensitive surface and massaged for 1 minute. The second phase of the study consisted of twice-daily at-home brushing with the toothpaste for 3 days. RESULTS: All one hundred and twenty-two (122) subjects complied with the study protocol and completed the study. There was good balance among the three groups at baseline. The mean tactile sensitivity scores for the new Pro-Argin formula dentifrice, the previously validated Pro-Argin formula dentifrice, and the control dentifrice were at baseline 14.88, 14.76 and 14.38, and after direct application were 28.90, 29.02 and 15.88, and after 3 days of brushing were 34.51, 33.41 and 16.00, respectively. The mean air blast scores at baseline were 2.11, 2.12 and 2.15, and after direct application were 1.21, 1.18 and 2.06, and after 3 days of brushing were 0.80, 0.83 and 1.93, respectively. Immediately after direct application and after 3 days of brushing, for both the tactile and air blast sensitivity scores, the differences between the two dentifrices containing 8.0% arginine and the control were statistically significant. There were no statistically significant differences between the two 8.0% arginine dentifrices immediately after direct application and after 3 days of brushing.