Objective: This paper presents the results of one of two eight-week dentin hypersensitivity clinical studies in which the efficacy of a novel toothpaste containing 8.0% arginine, calcium carbonate, and 1450 ppm fluoride as sodium monofluorophosphate (MFP) was compared to that of a benchmark commercial toothpaste containing 2% potassium ion, dosed as 3.75% potassium chloride, and 1450 ppm fluoride as sodium fluoride (NaF). Methods: An eight-week clinical study, with eighty patients, was conducted in Rome, Italy using a double-blind, stratified, twotreatment design. Tactile sensitivity assessments, as well as air blast sensitivity assessments, were used to compare the efficacy of the two products. Results: This clinical study showed that the new toothpaste containing 8.0% arginine and 1450 ppm fluoride as MFP in a calcium carbonate base provided a significant reduction in dentin hypersensitivity when used over a period of eight weeks. The study also showed that this new arginine toothpaste provided significantly greater reductions (p<0.05) in dentin hypersensitivity in response to tactile (37.0%, 30.0%, and 12.2%) and air blast (23.9%, 32.0%, and 29.3%) stimuli than the commercial sensitive toothpaste containing 2% potassium ion and 1450 ppm fluoride as NaF in a silica base, after two weeks, four weeks, and eight weeks of product use, respectively. Conclusion: A new toothpaste containing 8.0% arginine, calcium carbonate, and 1450 ppm fluoride as sodium monofluorophosphate (MFP) provides significantly increased dentin hypersensitivity relief (p<0.05) compared to a commercial sensitive toothpaste containing 2% potassium ion after two weeks, four weeks, and eight weeks of product use.