Final answer:
The bacterium associated with aggressive periodontitis in adolescents is Aggregatibacter (Actinobacillus) actinomycetemcomitans, a severe form of periodontal disease causing rapid destruction of the attachment and bone surrounding teeth.
Step-by-step explanation:
The bacterium associated with aggressive periodontitis in adolescents is Aggregatibacter (Actinobacillus) actinomycetemcomitans. Aggressive periodontitis is a severe form of periodontal disease that can lead to rapid loss of attachment and bone destruction. Other bacteria such as Porphyromonas gingivalis and Prevotella intermedia are also involved in periodontal diseases, but Aggregatibacter actinomycetemcomitans is specifically linked to the aggressive form seen in younger individuals. In the context of periodontal infections and oral health, the progression from gingivitis to periodontitis can result in receding gums, exposed tooth roots, and if untreated, further complications including tooth loss.