Clinical evaluations of all subjects will be done at 2-weekly intervals, namely baseline, 2 weeks, 4 weeks and 6 weeks of each treatment phase. Both adjacent teeth and gingiva at test sites will be scored for the Rustogi Modification of Navy Plaque Index, the Modified Gingival Index (Lobene 1986) and the Modified Papillary Bleeding Index (Barnett 1980). A plaque disclosing agent will be used to identify the location and amount of plaque. Additionally, gingival trauma will be assessed as presence or absence of signs of trauma in the marginal and papillary gingiva of adjacent teeth. The facial and lingual surfaces will be examined visually for gingival lacerations. Presence of laceration, floss cut, or demarcation line/indentation at the site will be scored as one, while a score of zero (0) will be recorded in the absence of any signs of trauma. The score per subject will be obtained by totaling all scores and dividing by number of sites examined (Carter-Hanson 1996).