[A.a.: the bacterium with the long name].

The introduction of Kodak's chairside test kit, Evalusite, for Actinobacillus actinomycetemcomitans (A.a.) and two other oral bacteria has stimulated this study of the relation between A.a. and periodontal destruction. A.a. has been associated with oral abscesses, brain abscesses, endocarditis and localized juvenile periodontitis. However, in all periodontal studies A.a. also has been observed in 'ordinary' periodontal pockets and subjects without active periodontal destruction. Based on longitudinal studies it is concluded, that there is no proof for a causal relationship between A.a. and periodontal destruction, that the detection of A.a. is not indicative for future alveolar bone loss and that the sensitivity of a test of A.a. is too low for the diagnosis of progressive periodontitis. The sheer presence of A.a. in spite of its virulence factors is not sufficient to cause periodontal destruction. It is stated that, in order to prevent overtreatment and medicalization, the use of bacteriological tests and broad spectrum antibiotics should be restricted to patients with progressive periodontal destruction not responding to standard treatment.