2. Main features of AAP 1999 classification system
i. Comprehensive section of gingival diseases is included in this classification.
ii. There is replacement of the term adult periodontitis with chronic
periodontitis, since epidemiological evidence suggests that chronic
periodontitis may also be seen in adolescents.
iii. There is elimination of separate categories of rapidly progressive
periodontitis and refractory perio-dontitis because of the lack of evidence
that they represent separate conditions.
iv. There is replacement of the term early onset periodontitis with aggressive
periodontitis largely because of the clinical difficulties in determining the
age of onset in many of these cases. The author of this new classification
also questions the use of the term juvenile periodontitis for the same
reasons. They have replaced the term with localized and generalized
aggressive periodontitis. The term aggressive was added because bone
and tissue destruction occurs rapidly as compared with other
periodontitis.
3. Main features of AAP 1999 classification system
v. A new classification group of periodontitis as a manifestation of systemic
disease has been created and this includes those cases of prepubertal
periodontitis directly resulting from known systemic diseases.
vi. There are also new group categories of abscesses of the periodontium,
periodontic – endodontic lesions and developmental/acquired
deformities/conditions.