One hundred and eighty-seven patients participated in a six-month study to evaluate the calculus-inhibiting effect of a zinc citrate dentifrice compared to Crest Tartar Control and a placebo, Crest Regular. The findings demonstrate a statistically significant calculus prevention benefit over Crest Regular for both Crest Tartar Control and a 2% zinc citrate/silica product. Compared to the control, the zinc citrate product reduced calculus formation by 32.3%, and Crest Tartar Control reduced it by 21.4%. These findings also demonstrate no statistically significant difference in stain or soft tissue status among the three dentifrices. All products were found to be safe to oral tissues and acceptable for taste.