Gingival bleeding in an experimental clinical trial design.

An experimental clinical trial design is described in which the onset of gingival bleeding was used as an indicator of early gingivitis. Twenty-nine dental students participated in a double-blind crossover trial utilising chlorhexidine as a known plaque inhibitor. The onset of gingival bleeding was assessed in three ways, one of which yielded a statistically significant difference in favour of the active mouthrinse (P = 0.02). The method has a role in screening agents believed to be active against gingivitis.