This study was undertaken to establish the tartar control efficacy and long-term safety of a new dentifrice containing sodium hexametaphosphate. In a randomized, examiner blind, parallel group clinical trial, the experimental dentifrice with 7% sodium hexametaphosphate (5% hexametaphosphate anion), a non-abrasive cleaning agent that provides whitening and tartar control benefits, was compared to two currently marketed controls, a regular sodium fluoride dentifrice and a triclosan/copolymer dentifrice. The 8-month trial model included a 2-month pretest period to establish calculus formation after prophylaxis, and a 6-month test period to evaluate anti-calculus efficacy and safety. Following the pretest period, 551 subjects were allocated to one of the three treatment groups and then monitored for calculus accumulation and soft tissue tolerance. After 6 months, the sodium hexametaphosphate group exhibited superior calculus inhibition compared to the regular sodium fluoride dentifrice and triclosan/copolymer dentifrice (p < 0.01). Over the 6-month observation period, the sodium hexametaphosphate and the marketed control dentifrices were comparable in terms of adverse event type and severity, and no subject discontinued treatment due to an oral soft tissue adverse event.