In the Phase 2a portion of the study, the efficacy of the antiplaque chewing gum in reducing existing supragingival plaque and gingivitis will also be assessed. Plaque will be assessed using the Turesky Modification of the Quigley-Hein Plaque Index (PI, Turesky et al-1970) and gingivitis will be assessed using both the Modified Gingival Index (MGI, Lobene et al-1986) and the percent of bleeding sites on gentle probing (BOP) using the methods described in Ainamo and Bay-1975.