The effects of tartar-control toothpaste on the oral soft tissues. Ninety-two dental and dental hygiene students completed a double-blind, controlled clinical trial. The purpose of the trial was to evaluate the effects of toothpastes, in varying concentrations of flavor and tartar-control agents. Four formulations of toothpastes were assessed: (A) control-low flavor with no tartar control; (B) medium flavoring with medium tartar control; (C) high flavoring with medium tartar control; and (D) medium flavoring with no tartar control. Soft tissue reactions were assessed objectively and independently by three examiners. Subjective perceptions about each toothpaste were gathered by a structured, open-ended questionnaire. The "tartar control" toothpastes, B and C, resulted in statistically significant (p less than 0.005) higher rates of mucosal reactions (e.g., ulceration, sloughing, erythema, migratory glossitis) than the "non-tartar control" toothpastes A and D. When the oral mucosal reaction rates were adjusted for multiple clinical observations within each subject at the same point in time there was no statistically significant (p greater than 0.05) difference between male (0.25) and female (0.28) subjects. In this study population, the order of preference was observed as toothpaste A greater than D greater than B greater than C. The major reasons for disfavor were burning sensation in toothpastes C (2.4%) and B (4%). 