Both Capnocytophaga spp and Prevotella intermedia were the most frequently detected microorganisms in a study, which also noted that Capnocytophaga spp was the most prominent bacteria in subgingival samples of patients with aggressive periodontitis.An impaired ability of peripheral blood lymphocytes to react to chemotactic stimuli is found in the majority of patients with aggressive periodontitis. As well as Aggregatibacter actinomycetemcomitans being associated with this, the synergism of the disease also accounts for both Capnocytophaga spp and Porphyromonas gingivalis. Pathophysiology
Aggressive periodontitis is a multifactorial disease with many complex interactions including host factors, microbiology and genetics. Host defences involve multiple factors; saliva, epithelium, inflammatory response, immune response and chemical mediators. The inflammatory exudate in the gingival tissues and gingival crevicular fluid is mostly polymorph neutrophils but also includes B cells and plasma cells. The neutrophils may show an intrinsic functional defect and respond abnormally when challenged by certain pathogens. The plasma cells produce specific antibodies in response to the periodontal pathogens, which diffuse into the gingival crevicular fluid. They produce mainly IgG, with some IgA. It has been suggested that these gingival crevicular fluid antibody levels could be potentially useful in the development of a vaccine. Patients with localised aggressive periodontitis have large amount of Aggregatibacter actinomycetemcomitans specific IgG2. This is suggested to be protective against wider spread periodontal breakdown. However, patients with generalized aggressive periodontitis have decreased ability to mount high titres of IgG to Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans.
For instance, diabetes is proved to be associated with periodontitis- it is a major risk factor when glycaemic control is poor. The rate of loss of attachment and bone loss is rapid.Loss of attachment refers to the destruction of periodontium whereas the bone refers to the alveolar bone supporting the teeth. The loss can be determined by using a calibrated periodontal probe and taking radiographs of the dentition. Usually the loss of attachment is greater than 2mm per year. Aggressive periodontitis runs in the patients family.Familial aggregation of aggressive periodontitis is often discovered by taking a thorough medical history of the patient. The patient is said to have a high genetic susceptibility to aggressive periodontitis. Many studies have shown that genetic factors contribute to the pathogenesis of this disease. In this case, the manifestation of aggressive periodontitis is believed to be the result of genetic mutation, combined with environmental factors. Secondary features
Secondary features are characteristics which are frequently seen but not always present in every patient diagnosed with aggressive periodontitis. The severity of periodontal tissue destruction is out of proportion to amount of bacteria present.The amount of bacteria is often indicated by the level of dental plaque. This feature implies that when aggressive periodontitis is present, loss of attachment and bone loss tend to occur even if the plaque level is low. High levels of Aggregatibacter (or Actinobacillus) actinomycetemcomitans and, in some populations, Porphyromonas gingivalis.These gram-negative microbes are considered the chief aetiological agent of aggressive periodontitis.