Plaque-host imbalance in severe periodontitis. A discussion based on two cases.

One child and one adult with severe periodontitis were investigated for relevant systemic factors and predominant periodontal pocket bacteria. The child had a chronic neutropenia, the adult late yaws, a chronic iron deficiency and possibly rheumatoid arthritis. The predominant organisms in both pocket floras were gram-negative cocci showing occasional filament formation and resembling strains of Bacteroides asaccharolyticus and possibly Actinobacillus actinomycetemcomitans described by others. There were indications that the flora was determined by the host response rather than vice versa and that thorough systemic investigation may aid the efficient diagnosis and treatment of patients with severe periodontitis.