The effects on indices of gingivitis/periodontitis will differ between study arms in which the titanium dioxide semiconductor toothbrush is used, compared to an otherwise identical toothbrush with an inert resin core in place of the titanium dioxide semiconductor.

Organic acid producing anaerobic bacteria are implicated in the development and progression of gingivitis and periodontal disease (Brill, 1962; Kleinberg, 1974). The disease process manifests as periodontal inflammation and tissue destruction (Oliver et al, 1969). Although relatively crude methods are used for routine clinical diagnosis and monitoring of periodontal disease (eg, probing for gingival pocket depth and bleeding), sensitive and reproducible measures of periodontal disease have been validated (Oliver et al, 1969; Löe et al, 1965; Egelberg, 1964; Golub et al, 1976; Borden et al, 1977).

By the Lewis definition, an acid is an electron pair acceptor. In the presence of light &/or electrical induction, valence electrons from a wetted titanium dioxide (TiO2) semiconductor will donate electron pairs to neutralize organic acids. Whereas a tooth surface is negatively charged, plaque has a net positive charge, and in part, ionic attraction contributes to the adherence of plaque to the tooth surface. Donating electrons to the plaque will alter polarity and diminish the ionic attraction between the plaque and the tooth surface (iontophoretic effect).

Thus, in addition to the established mechanical benefits of brushing, the flow of electron pairs for disrupting ionic bonding of plaque to the tooth surface and neutralizing bacterial organic acids, may confer an advantage over a conventional toothbrush (Hoover et al, 1992; Niwa et al, 1989; Kusunoki et al, 1986). There is some evidence that the electrons may also interact with bacterial coenzyme-A to have an antibacterial effect (Morioka et al, 1988; Onoda et al, 1996).

Inclusion Criteria:

• 30 to 70 yrs of age
• mild-to-moderate periodontal disease
• dentulous

Exclusion Criteria:

• any unstable medical condition
• pocket depth > 5 mm