The problem of the taxonomy of the fusiform bacillus of acute necrotizing ulcerative gingivitis (Vincent's gingivitis).

The characteristic microscopic appearance of the fusospirochaetal complex in smears from patients with acute necrotizing ulcerative gingivitis has long been regarded as virtually pathognomonic of the disease. Unfortunately there is considerable confusion surrounding the taxonomy of the fusiform organism in the fusospirochaetal complex. The conflicting views appear to be irreconcilable and a re-evaluation of the taxonomy of oral fusiforms is urgently required.